First signs of a new build

 This week, I scarphed together two lengths of soft maple.  Why maple?  Because I can get it in approximately 8-foot lengths of 1/2" thickness by 8-9" width at an okay price.  It is a hard wood destined for a canoe-styled hull.  I used an 8/1 scarph ratio which is more than required.  The scarph was made initially with a hand power plane for gross reduction, then followed with a belt sander and medium grit.  The resulting surfaces were flat and mated well.  Epoxy adhesive was followed by clamps.  I have three hand belt sanders.  Why didn't we have them in junior high shop class!  Planes can produce 'chips'; belt sanders never do.

   With epoxy and paint, also kept indoors, weather will not be a factor for the maple in this hull. Once scarphed together, I ran the combined board through a thickness planer to bring the thickness down to a uniform 7/16" (0.435").  Why that thickness?  Because I wanted a balance of weight, strength, and flexibility for the slight rocker planned.  These were rough boards when received, thickness was not uniform, and they initially were not entirely straight.  I corrected the side curve with a hand plane and frequent checking with a straight edge.  The product now is straight, uniform, and has the flexibility desired while retaining sufficient strength.  This will be the plank keel creating a foundation, tying all the frames together. 

Today, I bought lumber for the frames: knotty alder.  Why knotty alder?  It is a beautiful hardwood, but relatively light, and at a reasonable price.  Of course, I hand selected the best boards and bought excess (perhaps enough for a next hull).  The drawback is the knots present but, for the frames, I will be bonding together rather short lengths of wood.  I think I can work around the knots. 

New lumber.  The keel is maple, overall length 136".  Current width is 8".  The other boards are 1/2-inch-thick knotty alder.  As you can see, the knots are not too distracting.  I can buy 1/2"x5 1/2" boards, which I can't produce on my home saws.  The frames will be 1/2-inch thick, and most will be 1 1/2" wide, but with 5 1/2" overall board widths, I will not be limited if I want a wider piece for a frame.

There will be twelve frames, symmetrically spaced fore and aft.  These are full-size rosin paper patterns.  At the turn of the bilge, I will need to use narrower strip planks to follow the increased curve.

I chose a 13-foot length with frames spaced 11 inches on center.  The length could easily be increased with 12 or 13-inch spacing.  Knotty alder wood was used, but I was able to avoid almost all of the knots.  Fifty-six total wood pieces were machined and bonded to make these frames.  I will need to notch these frames for the sheer and a chine.  

My next task will be to create the stems; they will add about 20 inches to the length seen here.  I will start with Douglas Fir 2x4" material to construct them.  The measured sheer piece when bonded will fix the frames at proper spacing.

The hull stems are now in place, ready to be bonded. Next the sheer will be better defined with a scarfed longitudinal.  I need to strengthen that area before I can turn the hull over for planking.  The half angle at the stems/ends is 18.12 degrees.  There will be small decks at the ends for which I need to add some support.

Many details were involved getting to this point.  That curved sheer strip is 157.7 inches long by calculation.  However, I didn't trust my calculations, so I made it a couple inches longer just in case I was wrong.  Then when fitting it, I wasted time recutting to the proper length of 157.7".  The intersection point with each frame was also precalculated.  Everything is held together with spring clamps currently.  A next step will be to mix epoxy and bond it all together.  At the ends where the sheer and stem and a short deck beam come together, the calculated intersections were perfect.  The task was to cut the actual wooden pieces to fit exactly with all the intersecting angles.  Hull length is currently 154 inches, but that is to the inside of the sheathing, when done it should be about 2 inches longer.

The curved laminated section of wood placed from deck beam to sheer illustrates where the edge of the small fore and aft decks will be when complete.  I plan to use a herringbone design of planks for decking.

I have doubled the sheer stringer and added another wood strip to define the major chine.  Next step will be to fair the hull in preparation for planking.  The lower portion of the stems currently have a rectangular cross-section and will undergo major reduction to a "V" cross section (like it appears at the sheer level).  Using a short straight section of planking, laid in the direction of the design mathematical projection, as a guide, I have found that an angle grinder with a coarse flap disc is best for achieving the needed reduction. 

The plank keel will also need to be routed to create a landing for the first plank, the garboard.  This will all wait until after the upcoming holidays.  

    

Designing a New Hull Shape

This hull started as a concept in my mind.

The initial boat type, pictured in my mind, was of a slender canoe which could be paddled with a double-bladed paddle.  Speed was not a goal, reduced weight (partial deck) and slightly more forgiving stability were the goals.  The first thing was to picture the midships cross section; a bottom slightly wider and flatter.  I 'played with numbers' in an equation, used to define the major chine.  I could alter the coefficients of X, Y, Z in parabolic equations to get the right length (X), width (Y), and upsweep (Z) that I was seeking.

Next, I needed to decide the X:Y:Z ratio in the bottom projection; get the midships deadrise desired with progressively steeper deadrise approaching the stems.  In order to achieve this, the major chine needed to be reconsidered.  Position and spacing of frames needed to be included as well as width of the keel.  The Y:Z ratio is determined by the desired deadrise angle amidships.  The X:Y ratio is determined by the bow half angle of the major chine.  

Creating the topsides is perhaps most critical.  At this point, I had to start over with all new numbers for the equation for the major chine; however, there were multiple choices/combinations to pick from.  Incorporating three more projections to create a more rounded topsides shape, I discovered, would result in a hull that was wider than desired.  I used a paper sketch to help decide the coefficients for my topside projections.  I had to choose a major chine equation with less beam (Y).  Iterative process, but I was making progress.

When I started to achieve harmony between all the equations and coefficients, I had more aspects to consider.  Just how slender do I want this hull to be?  What should the overall length be?  What should the sheer look like?  How much depth amidships?   Height at the stems?  Should I consider creating a transom at one end; should the hull shape be symmetrical or should one end be slightly more tapered?  But those factors are not requirements- they are choices to create the specific boat you want.

With the offsets already generated, I needed to make two more projections: first to see a lateral view of the stems and secondly to see the shape of the plank keel.  All offsets need to be charted on paper before I can visualize the result.  (Hey, all I use is a TI pocket calculator: no computer screen.)

Full-size paper patterns for the frames, stems, and keel are complete, a little drafting practice.  Not sure they are interesting enough to post (pencil on rosin paper), but the cross-section shape is satisfyingly rounded.  I plan to add some partial decking at the ends.  The major dimensions, as finally constructed, are 155" (13 feet) long, 29" wide, and 11" deep.  Weight is about 43 pounds.

Thus far, my description has only been in generalities, should I post a table of numbers?  It will be some time before I can start building.  I do already have the plank keel lumber on hand.  Next task will be designing the frames and developing a list of materials. 

Stacked frame patterns drawn on rosin paper. 

     

I ordered the white paint by mistake, but I like the appearance of the final product.  

What should I build next?

Current state of assembly.  I have been busy with other things (travel, home purchase, taxes) and am awaiting an online order for more epoxy.  This hull will be 13 feet long, but the mid-section is parallel between the center two frames; I could make it one foot shorter just by leaving out one section with all other dimensions unchanged.

 When we were out on a lake recently with our kayaks, I noted that rarely was speed the goal when paddling; we were just poking around in the channels of a flooded forest in a reservoir backwater, seeing ducks, geese, and even eagles.  And I thought, "I could build a boat for that type of outing."

I have started sketching out the dimensions for such a boat:  I imagined: a bit shorter, wider, and more open, less decking in order to reduce weight.  Right now, I am considering a hull 156" long and 30" wide, but I still have more numbers to calculate and sketches to create.  I envision it as a double-ended-paddle canoe, but right now I only have numbers to look at.   

I don't see any making any further modifications to my latest kayak design/build.  It fits our uses well, but the joy and challenge of building another boat is still calling.  This could be my next project.

Finally, a day at the local lake.  On a sunny day at 7,000 feet elevation, you need sun protection.  That is my wife, Dawn, in the kayak I built for her.

This kayak is similar, but not identical to my wife's kayak.  Just a few inches longer and a half inch narrower.

Planking the new kayak

 Sorry for lack of progress, but we have been busy (mainly traveling) for the past three months.  Now I am getting back to planking the new kayak design.  Starting from the keel, the first projection is comparatively wide, Thus, I used 2" wide planks for that section.  As the cross-sectional shapes start to include more curvature, I will switch to narrower planks.  Using no fasteners, many clamps are required to hold each plank in place while the epoxy adhesive cures.

A straight, full-length plank is placed butted alongside the keel, and its position is marked on all frames.  At the ends of the hull, a short plank is placed by hand, marked by hand with pencil, then removed and tapered to fit the open triangle between keel and full-length first plank.  It takes a small plane and some trial fitting.  A much smaller scrap of planking is similarly marked and adjusted to fill the remaining small space.  These pieces were then immersed in a bathtub overnight before being clamped in place to dry.  This is an area of maximum curvature, the soaking makes them more pliable when clamping, requiring less force.

The first full-length plank has been placed port and starboard, and the second plank has been clamped in place for a trial fit.  The planks may look straight at first glance, but almost every plank has a slight curve which needs to be accommodated or removed using a small plane.  There will be one scarph joint per side.

These are full length, straight planks.  As you see, the planks are already reaching sheer height.  Following planks will be tapered and less than full hull length.  I do cleanup frequently, light sanding, knocking off resin blebs, vacuuming, so that I can make a better assessment of progress and note any flaws to be corrected.

Creating and fitting these tapered-less-than-full-length planks is exacting.  Each one requires a scarph joint.  Each plank about 11 feet long by 1 1/2 inches wide and with slight curvatures instead of being truly straight.  This is definitely not for the beginner boat builder or anyone with limited patience.  Then you must wrap each plank around the ever-changing frame curvatures and come out with consistent results.

Soon, the hull will be sheathed up to the sheer level, and I will post some new photographs.  Planking the deck should be much easier, but the inside of the hull needs to be finished prior to decking.

Before I start on the deck, I really need to finish the hull interior (while I have access), and perhaps I should finish the hull bottom.  The bottom sequence will be to sand any gross high points, do a penetrating coat of unfilled epoxy, then sand lightly, then a fill coat of epoxy slurry for any low points, and finally sand in preparation for primer and a final paint job.

  

The view is from the starboard side of the stern.  If you look closely, you can see that there are three partial length planks which taper to a point short of the stern (also short of the bow).  With somewhat straight planks and a changing bevel to the topside frames, this is what you get.  Some clamps are present because that final tapered plank has not been bonded yet and is held in place only by the clamps.

The hull has now been sanded with an orbital sander and 60-grit discs.  I am waiting on varnish ordered from Amazon.com; Colorado has no dedicated marine supply stores.  I need to varnish the hull interior before beginning the deck.  No new photos because the sanding does not alter the hull sufficiently for much of a visual difference. 

I now have three coats of varnish on the hull interior, and the first decking plank has been bonded, port and starboard.  "The decking planks should be a comparatively quick task.  It is just a matter of trimming the ends."  Fitting the cockpit edging will be slightly more difficult. 

Contrasting planks, light/dark, planks many of which are only resting in place.  Cockpit edging also passively placed.  As I work towards the centerline, access to the underside of the deck becomes very limited.

What I wrote above is wrong:  Fitting the deck planks is an exacting task.  Those planks, as initially cut, have variations (mainly curves) which need to be accommodated.  If you plane the planks until they are truly straight, they may end up being noticeably narrower.  The deck is highly visible, and the boards have to appear uniform and centered.  The centerline reference constantly needs to be rechecked.  I spent time planing boards to get what was needed.  Anything more than about 1/4-inch variation stands out.  Joints need to be tight, but not so tight that resin is excluded.  I can't have resin-filled gaps showing with exposed wood grain.

All those loose planks were trimmed, epoxy was applied, and they were all set in place in one session.  I used bricks for weight to hold the planks in place.  What you see here is after further trimming and sanding.  Using bricks seemed like a risky method, but the result looks good.

The deck does not look as good as it should.... my fault.  I used too coarse sandpaper and did some cross-grain sanding which left scratches in the wood.  The first coat of varnish really made those scratches stand out.  I was too impatient.

I probably have 2-3 more coats of varnish to apply.  Then, I turn the hull over and start painting.  The blue stripe is painters' tape.  Should I paint the hull blue/gray with a white stripe (where the tape is), or reverse it? These are the colors I have on hand.  The completed hull weighs 46 pounds; not light, but it is size, not weight, that makes it awkward to handle.  The frame with keel, prior to planking, weighed 17 pounds.  I think that I prefer a more rugged hull rather than a lighter but more delicate hull.
  

Having all the right tools is such a blessing.  When on active military duty (moving often)), I had a very limited tool set.  Now I have a well-equipped shop; no fancy tools, but a variety of modest tools that can get the job done.    

 

Final finish, and I am happy with it.  In places, I was impatient, and the finish could have been better, but the design looks good.  Visitors have said, "Why don't you build these to sell?"  I expect that I will be selling the oldest one, but only to make space for new projects.  We are going to be busy traveling for much of the next year, so I can't put a time schedule on a future boat project.

We took my two completed kayaks out to a local lake recently, along with another couple who brought their own plastic kayaks.  There were wind and active powerboats (wakes) on the lake, and these kayaks handled everything okay.      

At this point, I am pleased with all the dimensions/ proportions chosen for this project. I am wondering if my use of a slightly wider keel plank will noticeably increase hull stability. 

Putting the Pieces Together

Keel and frames temporarily clamped together, the start of a new kayak.

 For all of my earliest boat-building projects, I used plywood sheathing.  For recent builds, I have used no plywood.  Part of the reason is due to the type of boats I have recently taken an interest in.  Smaller boats tend to have sharper curvatures requiring narrower panels for sheathing:  Why not just use solid wood for these narrow panels?  When you sand solid wood, there is no concern about sanding through one of the plywood layers.

Using solid wood for the frames does require more joining of narrow boards, but it also provides better strength by aligning all the wood grain in the proper direction.  I use epoxy adhesive except for the laminated deck beams; there I use Titebond III.  In bonding the multiple layers of the curved beams, you expect to get 'squeeze-out' to ensure complete bonding.  Epoxy is messy and hard to clean up in such situations.  I have been using Titebond in limited applications for many years with no failures.  These underdeck beams will not be exposed to much moisture.

Next step is to create the stems for this hull.  I usually start with 2"x4" lumber for these pieces.  I want plenty of bonding area where everything ties together at the ends of the hull.

Creating the bow & stern stems will be my next project.

Stems are completed, ready to bond the sheer strip in place

All the pieces appear to be aligning quite nicely with no strongback required.

I used full deck beams for all frames.  That will allow me to size and place the cockpit wherever desired, although I already have decided except for details.  The stems look chunky now, but, when fairing, they will lose a lot of mass in beveling the ends.

All clamps removed.  We are looking at the framework from the stern.

With proper clamping, all pieces fit snuggly at the bow.  At this point, the hull is 158" x 25", but it will get bigger when the sheathing is complete.

I am adding one more longitudinal member to define the major chine, where the bottom and topsides come together.  It is not strictly required; the bottom is a single developable surface (beyond the keel), but the topsides consist of three separate projections blended together.

Bow stem prior to fairing.  Because the stems have a continuously changing bevel, it is best to fair the entrance angle after the piece is assembled into the frame.  I consider this step to be more sculpture than typical woodworking.  You have to do this in steps, frequently stopping and checking wood removal with a batten until it all blends together.

Bow stem after fairing.  The best tools for this are an angle grinder with 40-60 grit flap disc and a belt sander with a 60-grit belt.  I have a power plane, but it does not handle this 'sculpture' as well.  The exact bow taper is x/y/z = 14/3.6/1.

The stern stem is faired in the same way but with a slightly different angle due to its greater taper.  The next step was fairing together all the frame edges that make up the outside of the framework.  Routing a landing area at the edges of the plank keel, was the final step in preparation to start planking the hull.

Unfortunately, I was distracted, not focusing sufficiently, and gouged the keel in a couple of places when free handing the full-sized router used to make this rabbet.  The keel edge is curved near the ends (for about three feet) and the bevel is constantly changing, so 'free handing' is a requirement.  The router blade rotates clockwise.  If you pass the router from right to left along a board edge, the blade spins along that edge like a wheel, and things go smoothly with moderate wood removal and using multiple passes.  But, if you slide the router from left to right, the router tip can dig into the wood; you will not be able to hold it firmly enough, and a gouge results.  Why didn't I recognize that initially!  Yes, it is minor and fixable, but still an impairment.

Now I start slicing planks.  Results will be delayed.  For the next 4-5 days, wet weather, including some snow, is predicted.  The cutting and planing produce ample sawdust which I would prefer to deal with outdoors.  My goal is for planks that will be 5.6 mm. (0.22") thick.

We have been gone for the past seven weeks.  Now we are in full Spring mode, although some rain in the weather forecast.  Hopefully, I can get back to this boat project soon.

  

  

New Kayak design, Part 2

Topsides Projections 

The hull topsides shape is created by adding surface projections and secondary chines.  The goal is for the result to form a smooth curvature rather than the angularity of a single hard chine.  For this purpose, a parallel projection is used with a constant ratio between the changes in the x, y, and z dimensions.  The first projection will use the ratio x:y:z = 7:1.8:1.5.  All projections will be directed from the major chine toward the center section of the hull.  The second projection will use the ratio x:y:z = 7:1.8:3.5.  The third projection will be vertical in the z dimension with z=9 at the sheer line.  From this an entire table of offsets can be created listing offsets for all the frames above the major (initial) chine.

Where do these numbers for the projection come from?  The half angle at the bow is 0.9" increase in beam (y) in the first 3.5" of length (x). Because we are plotting length (x) at 7" intervals, we double the numbers: 1.8" increase in y for every 7" increase in x.  This ratio will give us the desired plumb bow.  Increments of height (z) vary as we go from keel to sheer:  keel is horizonal; deadrise is 0.5" increase in z for 1.8" increase in y up to the major chine; 1.5" per 1.8" increase in y in the first topsides projection, 3.5" in the second projection, and vertical in the third projection.  Together, these values help create a curved midships frame profile from the bottom to the sheer.

If we connect these points with straight lines, we have a faceted surface with five projections from centerline to sheer.  If we connect these points with a French curve or flexible batten, we can create a somewhat (the major chine does not completely blend in) smoothly rounded surface with the exactness of mathematical curves and projections.  Using narrow planks for sheathing the hull will preserve the rounded cross section.

Bottom Projections

Next, the offsets for the area below the major chine are developed.  For a narrow hull, like a kayak, a flat bottom, transitioning to a gradually steepening deadrise to provide both stability and a rounded cross-section is a good choice.  A flat plank keel is the starting point and the foundation for the entire boat.  However, if the keel is too wide, the hull will rock and pound in waves.  Laterally, on both sides of the keel will be a constant x:y:z slope of 7:1.8:0.5 (15.5 degrees deadrise).  All projections below the major chine will be directed toward the ends of the hull. 

This is a complete table of all the dimensions used to create the ten frames.  These are exact dimensions* resulting from projections from the major chine and the two additional chines for the topsides.  (*except for four numbers at the sheer obtained by graphic solution)

Stem Profiles

The next step in creating the new design is to project down from the major chine to the midline (y=0) to define the stem profiles, bow and stern.  Most of these numbers are not exact but can be calculated to whatever accuracy is desired (usually to 0.01" accuracy). The equations used for these calculations are listed. 

Plank Keel 

We can also calculate the offsets for the plank keel.  At my lumber source, I was able to get a plank about 10 feet long and 8 5/8 inches wide; then bought a second plank because the proposed keel would be about 140 inches long.  The original hull design was for a narrower 7.2" wide plank keel.  To take advantage of the additional width, I changed the projected distance from the major chine to the keel at the hull midpoint from 1.5" to 1.35" which is reflected in the table listed below.    

The bottom portion of the table above shows the calculations for the plank keel offsets.  The width (y) is the same fore and aft, but the length dimension, measured from bow and stern stems, is reduced by 20% for the stern portion.  As a check on calculations, intersections of frame dimensions at the keel should be consistent with the listed keel width at each "x" frame position.  Also, the "x" intersection of each stem profile with the keel should be consistent with the ends of the keel where y=0. 

Keel Rocker

It can be seen that we are designing the entire kayak with accurate numbers before starting building.  Only one more step to include:  It is recommended to include "rocker" (a slight upward curve) in the keel of our kayak for improved performance.  This will change the keel taper and length and induce a small change to the frame heights toward the ends of the hull.  I used keel rocker of 0.1", 0.4" and 0.9" over the 14" frame spacings toward both stems.  Total keel length will be 140.5 inches with the bow portion ending 9.3 inches short of the absolute stem and the stern section 7.7 inches short of the stern.

The numbers given are enough to build the entire kayak hull.  I already have the keel cut out and tapered.  Although using plywood cutouts for frames would have been easier, the frames are roughed out by half-lapping sections of solid wood on top of full-size patterns and bonding them together.  Much needs to be done to finish the frames, and work on the stems comes next.

   

Creating a new kayak, establishing dimensions and offsets

 General Considerations

My goal was a nice-looking kayak for safe general use on lakes.  Something better than the plastic sit-on-top hulls at the sporting goods stores, but less demanding than the long narrow high-performance kayaks.  The plastic hulls are generally about 12 feet long or less and 30 inches wide or more.  High performance means a hull closer to 20 inches wide.  Most light duty trailer descriptions state "for hulls up to 14 feet long".  This provided general parameters for my design:  12 to 14 feet long and 25-30 inches wide.  Displacement is a tradeoff between length, width, and depth.  Displacement at a 4-inch waterline is often used as a reference level.

The first step in design for me is to mathematically describe a midships cross section and the initial (major) chine.  I chose a maximum half-width of 9 inches at the chine; curvature extending upward to the sheer would add about 4 inches to those 9 inches, resulting in a total overall beam of about 26 inches.  Generally, the bow of a kayak has a finer entry angle than the stern exit angle; thus, bow and stern are calculated separately.  Working with thin wooden planks, frames need to be spaced about 15 inches apart or less to provide fair curvature without unplanned deflection.  I always create a table of dimensions for length using twice as many exact points as planned frames to ensure exactness.  Also, the end of each calculated curve should include a short straight section with no further curvature because there is no lever to exert torque at the end point.  X denotes length starting from the bow.  Y denotes width starting from the midline of the hull.  Z denotes height starting from the initial plank keel position. 

Starting Calculations, the Major Chine  

Creating fair curves is simple; most useful is the trajectory curve, also called 'parabolic'.  Divide the curve into as many equal sections as you need to provide adequately spaced offsets while also considering the total offset required.  In this case, I chose 9 sections (each 7 inches long) with an offset increment: 0.1 inches.  At the starting point (0) the offset is 9 inches, full width amidships. At the next point (1) the offset is 0.1", reducing beam to 8.9 inches.  Next point (2) has an offset reduced by 2 squared (4) for a beam of 8.6".  Next point (3) has an offset reduced by 3 squared (9) increments for a beam of 8.1".  At each section, the beam is further reduced by the square of the section number.  At the end of the curve, the initial beam has been reduced by 0.1" multiplied by 81 for a resulting beam of 0.9".  At this point, a short section without further bend is added, 0.9" width Y and 3.5" length X of straight line.

Each of those numbers are exact.  This major chine is the basis for all projections above and below.  Yes, there are many numbers, but this provides close-spaced points of projection so that when you 'connect the dots' when drawing frames, stem profiles, and plank keel plan view you have adequate accuracy.  This is about twice the number of dimensions that I will actually use, but the additional accuracy is there if needed.

The angle of this short segment can easily be calculated as twice the total offset of the curve divided by the length of the curve.  For the bow section of this design, I used a total curve offset of 8.1 inches and a total curve length of 63 inches.  (8.1 X 2)/63= 0.2571 (a 14.4-degree half angle).   0.9 inches divided by 0.2571 equals 3.5 inches, resulting in a total length of 66.5 inches.  The initial chine curve needs to curve upward as well as in width to provide a proper bow profile.  For this, the same curve length is used but with an offset increment of 0.08 inches resulting in a total offset of 7.73".  The planned height, keel to sheer is 9 inches.  Curved deck beams will add to the hull interior height.

For the stern section, the sequence is similar except that the exit angle, and curve leading to it does not need to be as fine.  This is done by reducing the curve length (by 20%) while using the same total offset.  Instead of 3.5-inch sections, 2.8-inch length sections are used.  Five of these sections totals 14 inches.  The frame spacing will be every 14 inches both forward and aft.  Half angle at the stern will be 17.8 degrees.

Next, we start to develop the midships cross-section curvature and determine the parallel projections used to create the entire topsides.

(This entry is done in conjunction with the actual design and construction of a kayak.  To be continued.  I will try to add some diagrams for clarification.)   

                 

A leaner kayak

 While I am still adding varnish coats to the new deck of my current kayak, I am already thinking ahead.  The plan is to add a blue/gray stripe at the sheer on my kayak's white hull and then add a white stripe on my wife's blue/gray kayak hull.  Aesthetic touches to make the two boats coordinate more closely.

But I also have an idea for a new modified kayak hull.  With minor changes to the current offsets, I want to produce a hull 159 inches long by 25 3/4 inches wide with almost the same height (depth?) as our current kayaks, not drastically different, just slightly 'leaner' than what we already have.  It should be lighter and more cartoppable.  Every time I design and build something, I am always asking how it could be improved.  These are not meant to be high performance kayaks, just nice looking and functional.

I already have outline drawings for the ten frames, plank keel, and two stems that will be needed.  The most critical piece of lumber is the plank keel.  Looking for a plank about 9 inches wide, 11 1/2 feet long, and 1/2 inch thick was asking a lot.  Couldn't find what I wanted in one piece, so I bought two shorter planks and will scarph them together to get what I want. Anything thicker than 1/2 inch will add extra weight and be more difficult to bend for the keel rocker.  I plan to plane it down to 0.4-inch thickness.  

The culmination of my previous project.  I had to rebuild that trailer and replace the deck on the more distant kayak hull in the photo.  Yes, that is snow outside.

 

You may notice the previous kayak deck lying on the floor on the right side of this photo.  I can't think of any use for it; probably will end up cutting it into pieces for trash pickup.  The price of progress; the new deck is better looking.

I am going to start a new blog entry.  I discovered that the new 'leaner' design requires more than a minor change in my table of offsets.  Also, I want to explain (to remind myself) just how all those dimensions are obtained.

Boating is more Satisfying when the Boat is your own Design

 

I designed and built this 18.5-foot-long runabout which was completed in 2014.  Size-wise, it has ample space for up to six people.  The 75 HP engine is good for about 35 MPH, although altitude, load, prop pitch, and even wind resistance can be factors.  Someday, I would like to run it at low altitude to see how much more speed might be attained.  It is light and easy to tow, due to the wood/epoxy construction, which is important because here in Colorado there are very few nearby lakes.  We have towed it as far away as Coeur d' Alene, Idaho.   Being light also means that it takes less horsepower to move it through the water, and it is very fuel efficient.  The only drawback to being light is that when maneuvering for retrieval to its trailer on a windy day, wind can push it off course when at idling speed.

Behind my runabout in the above photo, "Mountain Dancer", the larger green and white boat is my brother's 27-foot Sea Ray cruiser.  It is ocean-capable and has twin engines totaling about 450 HP.  

This past weekend, we ran the boat on Ruedi Reservoir (7,800' elevation), near Aspen, Colorado.  The weather was perfect except for an uptick in wind speed during retrieval of the boat.  The weather this past weekend was unpredictable with quick shifts between sun and clouds or rain.  Fortunately, everyone did their part to properly position the boat and trailer.  The dock at Ruedi is pathetically small which didn't allow much space for handling of the docking lines.

A few years ago, when my brother, Jay, and I both had our boats on Jackson Lake, Grand Teton NP, his wife, Connie, made a short video of my runabout on the lake.  The scenery there is spectacular, and you can see the runabout moving smoothly across the lake's surface.  If we are lucky, you may be able to view this video on YouTube at the following address:

 https://youtu.be/X1m7WiJS7S8

                  

We have the full canvas enclosure for our runabout in case of bad weather or the rare choice to sleep aboard.

What is Next?

 I sold two rowboats during the past week, helping to clear out the shop.  I have one more that I want to sell. (Now sold to a gentleman in California; he drove here to get it.)  If you have been following my blog, you can see that as I build a design, I am always asking "What could I do better?"  Then the next build incorporates those changes.  The boats I am letting go are perfectly adequate but have been replaced with slight improvements, sometimes with only aesthetic differences.  And I am at a point where few new improvements come to mind on my rowboats.  A sailboat would be a different project, but the Colorado mountains might not be a good place for consistent winds and sailing.  

I have been looking for the proper trailer for transport.  I finally located one, but it needs work (23 years old) and modification; it had been set up for hauling bicycles.  I bought it; used boat-type trailers are hard to find in Colorado, especially light duty.  I have replaced the tires, inner tubes, bearings, and axles.  I exchanged its setup for bicycles with a 5 1/2' by 5 1/2' deck for small boats.  Next project:  I have discovered that not all the trailer lights work.  The wiring is old (obviously) and not well protected.

I need to get out on a lake with my newest boats; that use may suggest further improvements.  The boating season at the altitudes where we live, 7000+ feet, is only about six months long, making for a limited opportunity on our lakes. 

The blue/gray kayak was my first recent design attempt.  The natural finish on the second kayak is a design for my wife.  I already have ideas for an improved design to slightly reduce width and weight.

 

This trailer came with a short tongue and a long tongue.  I attach the short tongue for use while in the shop.  The trailer (a commercial build from California) has coil spring suspension and motorcycle-type tires.  New tires are not easily found, but I was able to get two from Ebay.com.

I had a contractor come by to look at some home repairs.  When he spotted my boats, that is what he wanted to talk about.  He told me to call him when I get ready to sell the next one.  My most recent sale was for $400.  The gentleman from California told me I am underpricing my boats.  1) Colorado is a boating desert.  There are few buyers here.  2)  Mostly, I care for an appreciative home for these boats.  Each one is a unique design and product.

UPDATE: With everything completed, we got out on a local reservoir today, and I learned some lessons about kayaks compared to guide boats.  My guide boats have a steeper deadrise but are more stable, not just due to the slightly wider waterline beam but also due to having two oars in the water instead of one paddle blade.  Two oars also make for quicker turns, but the kayaks had good directional tracking when paddling.

While we were out on the lake, at 9,000' altitude, the wind increased in gusts, and I gained appreciation for the influence of increased freeboard.  As the wind became stronger, it shifted, and we realized that we would be paddling to windward to get back to the launch area.  Those of you familiar with kayak design can laugh at this amateur (me) making mistakes instead of using a proven design.  For me, it is just another project which I can fix.    

How to fix the kayak with excess freeboard?  Why you simply take a circular saw and cut around the topsides about three inches lower than the original height.  Then you replace the deck beams and start planking the new deck.

  I am putting a new lower deck on a previous kayak hull.  I like the results using solid lumber rather than plywood; it allows more creativity.  However, it does take more work, not so much in bonding the planks in place, but in individually fitting the planks.  Beyond knots, cracks, or any other defect, almost no plank is ever straight.  Thus, each plank must be fit into place.  Edge-setting 2" wide planks is not reliable, and I do not want to perpetuate existing variations.  I start by marking any convexity/ concavity in the plank shape.  Adjacent planks must have the same shape with imperceptible curves.  I have straight edges (2', 4', 6') for checking and multiple planes for adjustments.  The deck will be 15 planks wide with the last plank centered on the midline.  All planks are bonded edgewise with epoxy as well as being bonded to the deck beams and sheer. 

The new cockpit will be tapered forward, similar to the shape for my wife's kayak.

All bonding completed.  All that is left to be done are sanding, varnish, and paint.  The curve used for the forward part of the cockpit is from the same curve form used for the deck beams.
      

Careers and a Hobby

 

My interest in boats, shared with my brother, started when our uncle gave us a decrepit plywood pram.  It was poorly cared for and leaked.  We sealed the seams with roofing tar and painted it with house paint.  Then we named it “Tar Baby” in honor of the tarred seams.  Later, our family bought a boat for waterskiing, a sport we learned to love.  Next, my brother and I each joined the US Navy Reserves when we reached 17 y. o. and while still in high school.

My Navy service included crossing the Pacific Ocean twice (LST hull, then destroyer), spending most of a year in the Mekong Delta, next providing coastal fire support, and finally cruising north from Vietnam to Japan for ship maintenance.  My nautical education began with navigation school in San Diego and subsequently continued with real life experience and onboard texts as my guide.

USS Askari, ARL-30, on station in the Mekong Delta.  As usual, barges and river craft alongside, our ship providing repair services for all of the Riverine forces in Vietnam.  A converted LST hull, this 325-foot-long ship had a top speed of less than 10 mph.

USS Preston, DD-795, taken October 1966, a year before I was assigned to her.  This was a WWII vintage vessel, capable of up to 35 knots (40 mph) but near the end of her service life.  As well as serving as plane guard for the aircraft carriers in the gulf of Tonkin, its six 5-inch guns were used for coastal fire support.  At 375 feet long, it would be considered small by today's standards.

One early morning, while on a training exercise off the coast of Mexico, I witnessed a rare event of the sun’s rays being bent, diffracted, by the earth’s atmosphere just before sunrise so that, for a few moments, I was able to see islands that were far beyond the visible horizon, more than a hundred miles away.  While crossing the Pacific, we went through the edges of a typhoon, experiencing huge waves crashing over the bow, waves sweeping across the deck, and the entire ship shuttering as the plunging hull intermittently exposed the propulsion screws from the seas.  From instances like this, I developed respect for the unflagging nature of the ocean’s power and its vastness.

With my girlfriend, Dawn, at the beach in Santa Barbara, CA.  She helped me with the model hull testing for my research paper.  (Great partner, still together 55 years later.)

After my release from the Navy, I went back to my mechanical engineering studies at the University of California, Santa Barbara.  The Pacific Ocean forms one boundary of the campus.  The school has a crew club (rowing), surfing team, and a fleet of sailboats at Santa Barbara harbor.  Taking a sailing class out of Santa Barbara, I was intrigued by the forces in play determining sailboat performance.  Joining crew club exposed me to the influences of wave versus frictional drag.  At the same time, I needed a senior research paper topic for my engineering studies.  Thus, I chose sailing hull design as the topic of my research paper.

I was able to design a system for tow testing scaled hull models in a calm swimming pool with valid and consistent results.  The drawback was that I needed to construct a series of model hulls with varying parameters to test the influence of design changes and be able to describe them mathematically.  Simple photos would not suffice.  Researching previous hull design information, sparse in the published literature, I was able to customize mathematical equations and methods of projection to describe a limited range of hull forms.

An outline of hull measurement methodology: stability & resistance (drag).

My research paper was successful with an "A" grade.  But my search for fulfilling employment as an engineer was not so successful.  Much of my duties consisted of reviewing architectural plans and financial data, looking for mistakes and ways to increase efficiency.  Our engineering department was blamed for project cost overruns; in response, I did a comprehensive review of the past ten-years construction bids (for projects to be built several years later) showing that, in fact, it was the marketing department failing to allow for price inflation that resulted in the cost over-runs.  The big boss was a marketing guy and did not want to accept my facts.  I was disgusted and started looking for alternatives to these petty office politics. 

Our Morgan 27 sailboat on San Francisco Bay.  A very nice ocean-going boat, but the worst purchase decision I have ever made.  Too many changes going on in our lives at that point to make such a commitment.  

I considered a degree in naval architecture, but, at a visit to UC Berkeley, was told that ship design had no future in the US.  Designing ventilation, plumbing, and electrical systems for ships would be a better pursuit.  I considered sailing around the world (even to the extent of buying an ocean-going sailboat), but after reflection, realized that was just escapism, avoiding difficult career choices.  My degree would be obsolete by the time I returned from such a voyage.

I considered medical school, but a suggestion from my wife, Dawn, changed my career path to dentistry, a whole new environment.  My focus became people: biology, chemistry, physiology, and psychology.  In our classes, little was said about the molecular structure of the materials we used, that was for engineers to know.  Our dental text included a chapter with sections written by one of my UCSB engineering professors, but it was given little attention.  Dawn encouraged me to apply for a military scholarship, not just for the financial help but also for the travel opportunities it provided.

Our first major assignment was in the country of Panama, near Colon, on the Atlantic coast.  When friends there asked me to be navigator in bringing the trawler they had purchased from Miami to Panama, I had the chance to use my navigation training once again.  I was very thankful that I had supplemented my Navy training with a text on Polynesian navigation, using nature instead of instruments, because their 'new' boat had little to offer for ocean navigation other than a compass and one chart.  We arrived safely on schedule despite engine problems.

I really enjoyed my career in military dentistry, not completely retiring until age 76 (including time as a military contractor).  There were many patients I could list where I was able to not just ensure healthy teeth but improve their lives.  That was always my goal.  Let me give one example: a woman (wife of a soldier) came to our office in the Netherlands in pain with her face swollen due to a tooth which had rotted off into her jawbone (no visible tooth).  It was a surgical extraction with ample drainage of pus, but I was able to treat her comfortably with adequate anesthesia.  After she departed, I told the receptionist, “I want to see the mouth that kisses her mouth.” (her husband).

Because her husband was a member of the US military, I was able to order him to come in for an examination.  Sure enough, he had significant dental problems also.  Neglecting your dental health can be grounds for separation from the military.  We treated both parents empathetically, comfortably, and were able to bring them into healthy, confident smiles.  Not just treatment, but education and motivation.  Then, they voluntarily brought their children in, and we were able to correct all developing problems.  We replaced fear, ignorance, neglect and shame with dental health and a confident future.  What better professional reward could I have?  This sequence was repeated with many other patients.  Being in the military, cost (other than not wasting taxpayer money) was not a factor.

Can I tell one more story concerning the Army commander’s wife in Germany who was a dental phobic?  I diagnosed a dental problem of hers before even seeing or talking to her (but I had treated her husband, the base commander, and he brought her previous radiographs to me).  His wife was talking to my wife by telephone when she mentioned that she had a minor toothache.  My wife whispered this comment to me.  I told my wife to ask her if the discomfort was on the lower right toward the back of her mouth.  She replied to my wife, "How can he know that!"

As a phobic, she had a past of visiting dentists only when forced by circumstances.  She would then take home any records generated with her at the end of the visit.  I had carefully reviewed all her previous radiographs (provided by her husband) before filing them and had noted a developing defect in that lower right area.  After her toothache was comfortably treated, she came in for a series of cosmetic dentistry appointments, completely overcoming her phobia.  How about another…. enough said.  I could go on and on.  Dentists tend to get little respect, but on multiple occasions I have witnessed the dramatic improvement in a person's entire outlook from a healthy, pleasing smile.  That is all the satisfaction I need.  

Designed and built here in Colorado for daytrips and waterskiing.

Was my engineering background to be forgotten?  No.  I went back to my senior engineering research on hull design using mathematical concepts.  Over the years, I have built 14 boats using my mathematical design approach and expanding on it.  While in dental school in Omaha, I built a canoe for the small nearby lakes and rivers.  While in Panama, I built a cartoppable sailboat for the beaches, and shallow reefs there.  While in Alabama, I built a twenty-foot, two-masted sharpie sailboat for the large reservoirs in that area.  During a ten-year period (residency, Board exams, clinic management) I was too busy for such projects.  Part-time work and then retirement have given me more time and a better workshop for my design ideas including two outboard runabouts.

A small kayak for my wife; the 13th boat hull I have designed and built.

I have enjoyed all of it: studying navigation, engineering, dentistry, woodworking.  My father, a high school graduate, taught me by example that being a professional does not require a college degree; it is your attitude toward the task at hand that makes you a professional.

Life is a process of learning and becoming; dreams evolve to plans, then to realization, while facing the challenges of new situations along the way.  We learn, grow, and find meaning as we explore the world around us.