The origin of the "Boat Bowl"
A few months ago my wife showed me a picture of a wooden bowl from a catalog and asked me if I could create something similar. I had a concept in my mind that I thought I would try "someday", so this was the opportunity to use it. I quickly drew and fabricated a bowl to prove the technique. It came out okay, so I made some bowls slightly bigger, realizing that bigger was actually easier when laminating and sanding the inside. Then she asked for a longer, more flared design, and I made several of those, including for a friend who liked the design. Well, as one who enjoys designing and building boats, you may guess what happened next. I took the design for the next boat I plan to build and simplified and scaled it to create a "boat bowl".
Another year, another boat
A new boating season is beginning, and it is time to recharge the battery, refill the gas tanks and get out on the water. However, after last season I thought of all the ways I could learn and improve from my last boatbuilding experience and create an even better design. I wanted something of the same size but more closely resembling a classic runabout and with a better integrated sun shade. After calculating the offsets and sketching out the results, I started drawing out full-size patterns. At about Christmas, I started putting together wooden frames. By themselves, the frames look like just a pile of wood scraps, but when you mount them on a strongback, align them using a laser, and start adding the keel and other longitudinal members, it begins to look like a boat. With the experience of building something similar, I have been able to move forward more confidently this time. Instead of searching for answers, I know how to handle the design and construction challenges at each step. Having purchased a new table saw has been a great help also.
I am now ready to make patterns for the exterior sheathing. The 6mm marine plywood will arrive soon. I hope to finish the sheathing (plywood, cypress planking, glass and epoxy) and sanding during the summer months when I can leave the windows open. Next fall will be time for an upholstered interior and other finishing details. Changes from the previous design include a constant deadrise (12 degree) hull bottom, chine flats, a straight sheer profile with the foredeck raised 5 inches, and reduced deck camber. This hull is meant for slightly more power / higher speed.
First season report
Boating season is about over for this year but it has been very enjoyable. The only changes I have made so far to the boat are to move the throttle control over about 1 1/2 inches away from the steering wheel, to allow more clearance, and to replace the plexiglass windshield with auto safety glass for a clearer view. After trying three propellors, we have boat speed up to 33 mph (at a 7500' altitude). The engine trim control allows us to bring the bow down in waves and trim it up in smooth water for more speed. My wife enjoys the boat which is important. She spent more time driving it than I did on this last trip. That is great; my great joy is to start with a vision, create a plan and then make it a reality. This winter I will start on a new boat.
We took the boat out this weekend and had a great time. We were part of an Antique & Classic Boat Society club get-together. We were surrounded by beautiful traditional mahogany runabouts. I had changed the engine propellor to one with a more aggressive pitch and the result was more speed- 28 mph. The engine was still achieving 5950 rpm, at the top end of its recommended rpm range, and I am wondering if an even higher pitch will bring the rpms down a little and improve speed further. You can see in the attached image that the boat's bow is out of the water at speed. This is due to the slight rocker in the run. By calculation, the bow should rise about ten inches to achieve its planing attitude, and I don't think that is far off. From a visibility standpoint, the bow rise is not an impediment. At low speed the boat rests at its marked waterline. The ETEC engine is so smooth and quiet, and we are still using our first six-gallon tank of gas. My wife is not much of a boater, but seems to really like this one. With the intense sun in Colorado, our bimini top is an essential.
Finally in the water
Springtime in Colorado. After ten days of cold and light snow, the temperatures finally got up in the 60's, and we were able to launch the new boat this week. Everything went perfectly. I had re-inforced the deck at the bimini support attachment points, put flotation foam in the stern, installed a new battery, and readied my list of supplies. Amazingly nothing was forgotten; everything performed as designed; and the setup-launch-retrieval was easier than expected.
Out of the Shop
I had planned on using beer and thirsty friends to get the boat out of the shop and onto a trailer, but then a I reconsidered the logistics of getting six friends here at the same time with late fall weather cooperating, and devised a new plan on the first warm day. As when I previously turned the hull over, I suspended ratcheting tie-down straps from the ceiling beams and lifted the boat up off its building cradle. Then I moved a small cart under the center of the hull and lowered the boat onto the padded cart. I backed the 8' wide trailer up to the 6' wide shop door; pushed the hull out the door, rolling on its cart, until about 8' of the hull was out the door and on the trailer; then simply finished winching the hull onto the trailer.
Crowley Marine was ready to install the engine, steering gear, engine controls, and wiring, and they recommended a canvas shop for the travel cover and bimini. So, in a short period of time, the boat is now basically ready for the water. Of course, there are always more finishing projects. I need to (1) reinforce the deck underside where the bimini fittings are fastened; (2) place flotation foam in the bow and stern; (3) touch up the cetol finish in spots along the sheer where it was disturbed when the sheer strip was placed. After pricing simple custom upholstery for the plywood-framed cockpit seats, I found that I could purchase quality standard bucket seats for less than half the price. I should get the seats in the next two weeks.
But with winter's snow in our yard and the ski slopes beckoning, that will all wait until warmer weather.
Ready to leave the shop
Painting is not my favorite thing, but I have been doing quite a bit of it to complete this build. I still need to do some touch up but I have been trying to get this boat out of the shop and onto a trailer so I can get the engine and controls installed. Of course the boat will still need cushions, and bimini top and a travel cover. The weather forecast mentions possible snow next week, so I am just a little late to launch this season.
Finally was able to get the transom and splash pan covered in glass and resin. I wasn't looking forward to this step. It was like developing the pattern for a garment; I had to make patterns for the complex adjoining surfaces using six different sections. Had to decide which edges to put tabs on so that I had overlapped joints, and had to decide the exact order of placement to minimize interference. All concave junctions for adjoining surfaces were first filled with a fresh fillet of resin putty to prevent dry spots where the cloth couldn't adapt to the abrupt bend. Most of the surfaces were vertical, so the cloth needed to be taped in place while I spread resin and tried to avoid drips and runs. Because the glass cloth distorts easily, I had to note reference points for careful placement. This covering helps not only to protect the wood, but also to add considerable strength to this area which will receive maximum stress from the engine. To my relief, this session went well. Next up will be covering the entire deck with glass and resin.
Thinking ahead, I started to finalize the windshield design. No experience, so I started looking at pictures of old launches to see how it was done traditionally and what might work on the narrow, cambered foredeck. I sat in the cockpit and tried to imagine how a bimini top will join to the top of the windshield. Because the entire boat surface is developable and mathematically created, I was able to select x,y,z coordinates for all points defining the windshield and then calculate lengths and angles for creation of a cheap plywood mock-up of the windshield. Looks pretty good, so now to select real wood and put together the actual windshield. This will be a nice side project while waiting for resin to dry on the deck.
