Thursday, February 04, 2016

Time to start a new boat

It was made clear to me several times over the past few years that I need a boat that I can carry out of the garage, put on my car, take off my car, carry it to the beach and launch, and then be able to do all of that in reverse. That means the boat, or at least the heaviest portion of it, needs to be in the vicinity of 50 pounds or less.

Ok, so I don't have a lot of upper body strength and one could argue that all I need to do is work out more. Well, that could be one solution, but a lighter boat should also be a faster boat and having a stronger upper body doesn't help in a pedal boat.

Given all of the information gleaned over the past many years, what sort of boat should it be?

Some things go without saying, but here they are anyway:
- Long (20+ feet), narrow (less than 1 foot), twin stabilizers
- Recumbent seating

What propulsion device should be used?

While paddle wheels are completely immune to seaweed and generally immune to rocks and shallow conditions, they are noisy, and splash water all over the place without fenders, and if fenders are employed then windage is a problem. If the paddle wheels are positioned near the stern, then they are less effective in waves. If they are positioned amidships, then they get in the way of boarding and general visibility. They are also fairly heavy, and have a lot of drag if one stops pedaling.

Propellers are not immune to seaweed, shallow conditions or rocks. They are generally quiet, and can be positioned near the stern where they can provide awesome steering enhancement, but are less effective in waves and nearly impossible to defoul reliably, or positioned amidships where defouling can be done by hand one way or another. With folding propellers one can coast for quite a distance without pedaling, though fixed propellers tend to be smoother in operation. Daggerboard propeller drives are generally more efficient, but seem to require more maintenance for their chains, sprockets and oil baths when compared with flexible shaft systems.

After a lot of thought I think I'll be using a flexible shaft system much like is on my V15-6m, though possibly with a belt drive instead of a chain drive.

The hull shape will be a little different from the V15-6m. Instead of a hull that tapers to a knife edge at the bow and stern it will taper only at the bow. From amidships to the stern it will remain wide and square. There will also be more rocker so that the bottom of the bow will be at least an inch or two above the water. The bottom of the stern will be at the waterline or close to it.

In order to better surf the waves the upper part of the hull from the bow to the cockpit will have a little less volume than the V15-6m, but much more of it will be distributed further forward. This is to help reduce the tendency of the boat to bury its nose in such conditions.

The stabilizers will also have more rounded bows, and a much more gentle slope from the bow to their middle.

The seat will be positioned at least 3 inches lower. Along with the generally wider hull this should help a bit with stability and enable the stabilizers to be positioned slightly above the water most of the time.

From what sort of materials should the boat be fabricated?

While okoume marine plywood looks very pretty even when an amateur uses it to make a boat, and it is very durable, it is also very heavy. So, there is no plywood hull this time around.

The relatively ugly but really simple solid foam and glass construction used for the V15-6m's new stabilizers has worked out quite well. With a few changes to the fabrication process it should enable a fairly light and adequately strong and crash-worthy boat. Foam is easy to shape, glue and repair, and it doesn't rot if it gets wet. So, foam it is!

Here are some photos of the initial work on the foam stabilizers. The quick and easy hot wire setup made using a PC power supply and nichrome wire taken from a dead electric heater does a pretty good job of cutting nice curves through 6 inch foam.
Hot wire setup, about to cut stabilizer
Hot wire setup
Stabilizer after curve cut with hot wire setup
Smooth cut remnant from stabilizer
New boat hull bottom panels (rough)
Stabilizers before smoothing edges
Cast Cadence propeller #1
Cast Cadence propeller #2


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