Unicorn, a small electric fantail launch

Drive and Steering FINALLY! The steering and drive systems took significantly longer to design and install than I was hoping, mostly due to many many mistakes, miscalculations, and lack of adequate planning. Very frustrating. Note: The orange cable in this picture goes from a battery on my work bench to a motor driver to test the drive system. Steering The steering system is electric with manual tiller backup. The black and white parts are 3D printed on my printer. The blue and silver blocky thing is a waterproof giant scale servo from the Radio Control (RC) hobby world. It has gobs of torque for being so small and should   be strong enough to turn the rudder. It is back-drivable so the tiller can be used to steer, without removing the servo. However, for electrical-safety reasons the servo's cable must be unplugged before using the tiller. The tiller is made from a large red oak board that I think came from Scholar's Retreat, aka THICUT, aka what used to be my grandmother'...

Glassing the interior This is what was I was working on over the last month. We call it the Bump Out. I removed 2 sets of double windows on the south west end of our sun room and pushed part of the wall out 18" so we could make the TV look built-in and have storage for Vicky's knitting supplies and a small cubby for Poppy to sleep in. Back to Unicorn! I put 8oz cloth (also called 8oz woven roving) on the entire interior surface of the hull to stiffen it and to make the interior more durable. As I mentioned in my previous post, this is the "expensive" cloth, but I STILL had problems with bubbles. They are less visible in this thicker cloth but what a PIA. Even with the thick cloth, the hull construction is clearly visible which was intended. I also started working on the rudder assembly and drive system. It turns out that my initial (apparent) success in drilling the drive shaft hole straight was not so successful afterall. If you look really closely at the picture sh...

Turning Unicorn Upright First, a short update on finishing the hull. I ended up sanding off the poly (again) and some of the paint, putting on two new coats of paint with a foam brush, "tipping" the paint smooth-ish with the foam brush, and then put on three coats of poly in quick succession in the hopes it would "pull flat". The finish is better but still not actually smooth. You get what you settle for. The Big Day (Poppy provided emotional support) A major step in small wooden boat construction is turning the hull over. There are several techniques to do this depending on how big and how heavy the hull is, and how many helpers you have. Unicorn is about 14 1/2' long and I think the hull weighs roughly 75lbs. Since it was just me doing the task, I elected to use the two-lift method and go very slowly . The whole process took most of an afternoon, following, generally, these steps. build a frame or cradle(s) to support the hull when it is upright. This frame is...

Painting the Hull TL;DR:  Lots of text explaining finishing the boat. Read on for hopefully a little education and entertainment, otherwise just look at the few pics. The original idea was to leave the hull unpainted, showing the wood strip construction. The cheap fiberglass I bought left bubbles that showed the weave of the fabric. No amount of poking at the fabric with an epoxy-soaked chipping brush would make the bubbles go away. But fiberglass is an expensive part of the whole project, so I stuck with the "bad" stuff. The only way to hide the bubbles was to paint the hull. I really did still want to show the hull construction, so I sanded off all the fiberglass in the fantail stern, bought small piece of (expensive!) "good" fiberglass and re-glassed that area. It was SO much easier and faster using the better fiberglass. Lesson learned. The wedge shape shown in the pick below is an attempt to have something other than a boring straight line joint between the woo...

Rudder and Rudder Shaft The hull is sanded and ready for paint and varnish, but I've also worked on the rudder. It was a daunting task. I calculated the size using some formulas for much larger ships, then rounded up a little, then made the actual size a little smaller. It looks rather large for such a small boat, but at the low speeds Unicorn will be moving at a larger rudder will give more control. The remaining part of the oak board from Home Depot, that I used for the breast hook, was almost exactly the right size. The fact that it is a nearly perfect quarter sawn board would make it well suited for the forces on a rudder -if it was laminated between 2 thin boards with the grain going at right angles to the grain of the main board. This makes it into a 3 layer plywood-like board. Glue Layup of the Rudder. Note the cobbled-together long reach clamp coming down from the top. The central stripes are the cross grain of the 3/4" quarter sawn oak board. The grain going left-righ...

 Just a note: My boathouse was too cold to work in over the winter. After much research and education, I have figured out the least expensive and lowest effort method to get more power into the boathouse so I can have enough electric heat to keep it comfortable thru out the year so this should not be a problem this winter. Even if I finish this boat over the summer, I already have thoughts and hopes to build another perhaps smaller boat as soon as Unicorn is launched! For the curious, I have purchased a 50' 4 wire twist lock extension cord rated for 30 amps. This will plug into the existing 30 amp generator input (turned into an output) on the house. This provides 30 amps from each phase (like an electric clothes dryer) from the house's breaker box. I buried the cord about 6" underground. It comes up out of the ground at the boathouse and goes up the outer wall and in thru a hole in the wall. It ends up right over my workbench. ...and now for the cool part... It turns out ...

Boring the Prop Shaft Hole Unicorn will be moved thru the water with a propeller powered by an inboard electric motor. While the drive system layout uses modern components, boring the prop shaft hole was done with very low-tech tools. (Yes, I'm skipping over the fiberglassing effort for now because a)it's not quite done yet, and b)it looks awful. 😕 More on that in the next post. ) Here's a picture of the tools used to bore the prop shaft hole. The thing in the foreground is a modern version of an ancient hand drill, a Brace (sometimes called a Carpenter's Brace). This simple tool can produce the large twisting force needed to turn the 7/8" diameter auger bit I used. The picture is from after the hole was bored, but you can see extending out of the Brace is a 24" drill extension. The 17" auger bit in this picture is already completely inside the keel and hull. Here's the setup of the process. The goal is to bore the hole exactly down the center of the...