the most boat that can be built in 9 consecutive days

Peter, I have no problem with S&G. And if you want to modify an existing design to use this method, knock yourself out. My point regarding the conversion is that making a change like that typically takes a fair amount of trial and error and head scratching during construction. You simply don't have the time based on the schedule you're defining for yourself. You need a solid design that you can crank on right out the gate.

Good luck on it, and have fun.

 

"Could Peter pre-construct side panels complete with stringers and wrap them around the bulkheads?"

Exactly as per instructions,
RR

 

I have nothing against stringers, I just know they will add significant construction time to the build. I can probably prescarf them and cut out bulkheads ahead of time, but if I have to build a frame and then attache panels to that frame it just seems like one extra step. I built my waapa in s&g with no stringers other than the gunn'l and it turned out fine, lighter than design weight. But waapa is really an experimental platform by design, and there is little to really "screw up" on such a non-modern design...

I dont think I need a frame and stringers to "lock" the planking in place. But I realize that stringers will stiffen the panels. I just wonder what would happen if I used 6mm ply instead of 4mm and left the stringers out altogether... it would basically be monoque construction no? Or maybe I just have one stringer in the center of the hull planking for stiffness at the center if that wide panel only?

I mean I read about a buc 24 being built in 4mm ply for racing. The panels flex alot according to the builder, but the boat is decades old and still competitive (even has lifting foils in the amas). If that boat was built in 6mm but without stringers wouldn't it be the same effect?

 

Peter, my new 24 foot cat hulls have two stringers each side, in addition to the sheer clamp and the epoxy-tape chine joint, and is planked with 6 mm ply. Even so, I'm skimping a bit on what some designers would regard as necessary support for the topside panels. The rule of thumb is that stringers shouldn't be much more than 12 inches apart on such a hull panel, and mine are a little further apart than that, so I have some concerns about oil-canning, especially in the forward sections that take the brunt of wave impacts. I have a bulkhead 3 feet aft of the bows and another 6 feet aft, and then I get the rigidity of a glassed-in bunk flat at the beginning of that crucial area 30 percent aft of the bows. I notice that in the Acorn, the bunk flats are well aft.

Of course, mine is a cruising boat, and as a consequence has heavier scantlings than what would be appropriate for a racer. Much depends on what you plan to use the boat for. I would be very reluctant to disregard any of Richard's scantlings. His boats are usually very competitive for their size, which implies that his scantlings are as light as he feels he can get away with. But he's a very helpful guy, so ask him about this stuff. He'll probably be able to give you better advice than all of us put together.

 

I e-mailed Richard. I also asked a similar question in the buc 24 builders forum, which is another design I had considered.

 

How about two hulls side by side on a trailer you can drift apart when launched. The cat width can be anything you want and a sturdy trampoline. The hulls could be 1m200 wide and is wide enugh for conservative live aboard. The cabin is tricky, heavy and windy.

I did a design before and there is a way to get a decent cabin if you trailer it seperate. Otherwise the hulls will have to be the cabin. 8m is about the smallest you can go to fit the basics. Small outboards, and an aft mast setup with one single sail.

 

I think stitch and glue is a bit heavier and uses more epoxy which is definitely more expensive. If you can find plans that work each way compare the difference.

 

The most boat that can be built in 8 days will be the boat with the fewest parts to the hulls. This will be a dory style with thick skins allowing monocoque construction. The quickest build technique (and the one that is least affected by bad weather/hot or cold days) is flat panels from foam and glass. The timetable for 2 people to build the 35' harryproa that was entered in the WoodenBoat design contest (you might want to extend the ww hull by up to 20% in all directions to give a bit more space) would be something like:

In your basement: Set up a small table and vac bag or infuse the bulkheads. This will show you what is required. Precut as much foam and glass as you can.
Day 1: set up a flat table on sawhorses using alloy or steel beams to make it level and 9 8x4 sheets of mdf with melamine faces as a surface.
Day 2-5: Vacuum bag (or infuse) the 8 hull panels and the ww hull bunk panels, 2-3 panels per bag. The first shot will take all day, the last one will be done by lunchtime. Spend the "waiting for cure time" cleaning up the panels, removing inserts, etc.
Day 6: Join the lee hull panels by bending them around the bulkheads. The bulkheads and the panels are all male and female joints so are easy and accurate to join without a strongback or frames.
Day 7: Join the windward hull panels, using the same technique, but with the bunks as locators as well as the bulkheads.
Day 8: Contingency time or start on the beam panels, which are built the same way.

Worst case scenario is that it takes all 8 days to make the panels. In which case, take them to the boatyard and stack them in the corner until you have a couple of spare days to join them together.

You could also use ply but will be seriously constrained by the time it takes to shape stringers, make joins and apply epoxy to everything, although the latter (and the marking out of each sheet) could presumably be done in your basement before you start.

You could build a dory catamaran the same way, but the internals are more complicated and for the same materials, it will be smaller. 21' Acorn is a little heavier than 35' proa.

Why a harryproa? Obvious answer is that it will be faster, cheaper and safer for a given amount of materials. But for a bare bones cruiser, the biggest advantage is that in an anchorage where all the boats look alike, you will be different. This will get you more invitations to boats and houses with interesting people, showers, parties and decent meals than you know what to do with, which will extend your budget and your tolerance of roughing it considerably.

 

I have considered a proa rob in the vein of Russ browns jzero. And I really like ur designs. But I am on a budget, and between the cost of plans and of the carbon fiber specialized rig that you specify, plus the fact that foam panels cost more than double what plywood costs, ur 35' proa would really just cost too much...

 

If you want to construct the basic hulls in a few days Kelsalls KSS method might be worth considering. Uses foam/polyester which due to the cheaper resin is supposed to be similar to marine ply/epoxy in cost. He has a design which seems similar to what you are considering.

http://www.kelsall.com/Designs/KSSXKat23.htm

 

You did not mention budget, just the most boat possible in 8 days
1) The 35' harry in ply weighs the same as Acorn (21' cat) so the materials are the same. Incidentally, 25 kgs of epoxy will not coat 25 sheets of epoxy, much less glue and sheathe it, so treat the Acorn materials list with caution.
2) Foam panels cost the same as ply in Aus (see the spreadsheet of costs attached), but building the proa in ply is one of the options if you don't mind a little extra weight, and more time.
3) Plans for this boat are free as they are in the Design Competition.
4) Could use wooden or alloy masts, but the cost, build time and weight all go up compared to carbon (see spreadsheet). The carbon mast will last forever, the stayed alloy one will be an ongoing source of work and expenditure.
5) Jzero would be a good option, assuming you are a sailor of Russ' calibre, but you won't build it in a week.

rob

 

found an interior building space

So this is the building in which the boat will be built. It is now a pencil factory (one of the very few still existing I non-china). But originally it was a boat repair building. This helped to convince my father in laws boss to let us use a part of the storage area to build a boat, as the building is coming full circle.



We just have to clear it out and hang some lights, etc, maybe build a small work table from plywood. Btw those rollers on the floor each weigh 1 ton...

 

Hey---I know that building! Cool spot to work. Aren't you a lucky guy. A few weeks ago I built a 17' boat near there.
You will achieve so much more under a roof and with a somewhat controlled environment. Workbenches, shade, level surfaces, and the ability to leave things out yet locked up and out of the weather will make you twice as efficient.
Keep us posted on your progress and if I'm in the area I may stop and contribute to the useless opinion gallery.;?)

 

I know your not going down the cylinder mold path but you dont have to build two cylinder molds you use the same mold for both hull sides the pattern is reversed and the other hull side is cut off the same mold. The modern biaxial style molds make it easier to achieve a good hull shape without as much torturing of the formed panels.

Kurt has some flush decked designs with higher freeboard which arent as good looking but save building complex deck house shapes. All the best with your build any of the boats your looking at are a worthy build but I think you'll love the Bucc 24 it's a great boat.

summary of Cylinder mold construction by Joe small tri guy

 

http://i961.photobucket.com/albums/ae96/peterchech/2011-07-30_12-26-09_909.jpg

Much cleaner.

I prob wont start till october though, too much sailing to do now

Nothing against cm believe me, but kurts plans would prob put me over budget themselves unfortunately