Sunday, February 28, 2016

Glueing bottom of hull

Bottom of bow section
The Gorilla Construction Glue seems to work fairly well so far. I ended up using up almost the entire tube for the stabilizer floats and the deck, hull sides and bulkheads, as well as attaching the bottom of the bow section of the hull. A little excess glue ended up squeezing out here and there, but it was readily wiped off with a paper towel.
As can be seen from the top photo I used a variety of heavy objects and some clamps to form the 2 inch thick bottom piece against the other part.
After the bow section set and a fresh tube of glue obtained ($7 at Ace Hardware) the middle and rear sections were attached. Additional glue was used as a filler/caulking agent where gaps appeared between the pieces.
Bottom of central and stern sections
Once everything had set I then ran the orbital sander with shop vac attachment over the sides of the hull to remove high spots. This might have been a mistake. The alternative would have been to have filled in the low spots with some lightweight filler, say a mix of resin and microballoons, plus some light sanding. That would have potentially kept the hull shape a little more consistent, but would have added weight.
Glue has set
Regardless, the weight of the hull at this time is about 10 pounds. The fore deck wave splitter still needs to be added, which will probably be another 2 or 3 pounds, and then the glass will add a bunch more.

The bottom edges have also been sanded to a nice curvature (more towards the bow, less towards the stern. This was pretty quick and easy to do with a sanding block and long, even strokes. Yes - a longboard would probably work better to keep things more even, but I don't have one (yet).

Monday, February 15, 2016

Skeleton is taking shape

Side View Amas
Top View Amas
Progress is being made. The amas have been shaped and sanded, and they are ready for their skin to be applied.

The main hull has also been generally defined. It will be 21 feet long, 10 inches wide at its widest, and 6 inches thick in from the front of the cockpit to the just behind the seat. The bottom of the bow is 4 inches above the lowest part of the boat, and the stern will be 3 inches above the lowest part of the boat. There will be extra volume starting at the bow and ending before the cockpit to help keep the bow from burying itself in the waves when surfing.

Bow and cockpit sections, upside down
Side of hull at bow, checking for gaps
The skeleton of the boat is Foamular 250 "pink" foam insulation I picked up from Home Depot. There are two different thicknesses being used. Two inch thick foam is being used for the bottom and for the interior bulkheads in the cockpit area. It is also being used for the joining the three sections of the hull. One in thick foam is being used for the sides and top of the hull, as well as the fore and aft hull bulkheads.

Bow, cockpit, stern bottom and deck
The hot wire cutter was doing a lot of cutting today!

As an aside, it looks like I bought at least two extra panels of the 1 inch insulation. It doesn't look like more than one sheet will be needed for the added volume for the bow above deck.

Once the hull is glued together (using Gorilla Glue), the edges and the hull bottom will be shaped with a hand block sander.

My order for fiberglass, resin and pigment also arrived today. I had hoped to get 40 inch wide 5.6 oz S2 glass, but Fiberglass Supply was out of stock. They suggested substituting 30 inch wide 5.6 oz S2 glass, and I agreed. I'll just have to wrap the hull a little differently than I originally planned, which will put overlaps about every 27 - 30 inches down the length of the hull. Those overlaps will act like ribs and help stiffen the boat even more.

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