Carolina flare build and materials

OK mate, but that flare is the result of double diagonal planking ?

 

Two diagonal overlapping layers of plywood over longitudinal stringers. Not double diagonal because both layers are in the same direction. Photos of the Ocracoke 20: http://www.bandbyachtdesigns.com/ocracoke.htm

 

Previous thread about Carolina Flare designs:
http://www.boatdesign.net/forums/boat-design/carolina-flare-hull-51598.html

Slide show of another builder using cold molded plywood: http://www.baylissboatworks.com/built-for-you/the-process/

 

Double diagonal planking with plywood is quite common. The earlier boats were juniper on juniper. Then they started having plywood bottoms with juniper sides. The next generation was plywood all over. We build a lot with baltek planked sides and plywood bottoms. Many are now using foam core for the sides with plywood bottoms. There are all fiberglass boats, but they don't feel the same. Also, wooden boats catch more fish. The theory is that the sound they produce is different. The fact is that most tournaments are won on wooden bottom boats.

 

So, do alloy boats catch more or less than glass boats ?

 

Never seen an alloy boat in any of the tournaments.

 

Some boats do seem to get better fishing results than others, I'm doubtful it is because they are quieter though. Some of the best fishing I ever did was out of power cats with continual tunnel slap ! Alloy boats frequently sound like a barrel of marbles, but seemingly does not spook the fish. Don't know what it is that makes the difference.

 

Tom was your testing test published elsewhere? Can the formatted version be scanned and dropping into the thread, so the figures "column" appropriately? I think this is a candidate for the "Handy Information" thread.

I now understand your aversion to Dynel. I've used it, though not so much in recent years 90% of the time on decks, because of the weave and fiber/resin ratio.

I can see no reason anything about a boat's particularities will cause you to be more or less successful in tournaments. What I have noticed is the same boats seem to always do well or not so much, which is likely the guys aboard, not the hull build material. Racers see the same thing, with a handful of racers always seeming to be at the front of the fleet, while the rest are blaming their boat.

 

Well, blaming the boat does offer a convenient excuse at the end of a trying, fishless day ! I know some game boats on the marlin are claimed to consistently raise fish where others fail, that might be something to do with the exhaust note, rather than the hull material.

 

As is obvious, I am better with real things than computers but here is the abrasion data, hopefully in a readable form.

Paul, the article was published in BOATBUILDER when Keith Lawrence was the editor and that magazine was pertinent to our craft.


Abrasion Test Results

Sample--------------Sheath----------Abrasion time----Abrasion time-----Abrasion time-------Abrasion time per
---------------------Thickness (in)------(sec)---------------rel. to epoxy-------rel. to 9oz FG------unit of thickness
----------------------------------------------------------------------------------------------------------------Rel. to 9oz FG
Plain epoxy---------0.018--------------40-----------------------1.0-------------------0.59----------------------0.53--------
9oz fiberglass------0.02----------------66-----------------------1.7-------------------1---------------------------1-----------
2 layers 9oz FG----0.039-------------133-----------------------3.3-------------------2---------------------------2-----------
Dynel----------------0.043-------------250----------------------6.25------------------3.8-------------------------1.76-------
Vectra---------------0.032--------------153----------------------3.8-------------------2.3-------------------------1.43-------
Xynole--------------0.053--------------436--------------------10.9-------------------6.6--------------------------2.5--------
Weights of these materials may be of interest also.
Sheathing weights:
One coat of epoxy = 0.036 lb/sq ft
Two coats of epoxy = 0.059 lb/sq ft
Three coats of epoxy = 0.081 lb/sq ft
6 oz FG cloth w/3 coats epoxy = 0.142 lb/sq ft
10 oz FG cloth w/3 coats epoxy = 0.195 lb/sq ft
XYNOLE cloth w/3 coats epoxy = 0.36 lb/sq ft
KNITEX 1808 biaxial (non woven) FG cloth w/3 coats epoxy = 0.46 lb/sq ft
These sheathing weights are approximate and will depend on how the individual applies the materials but may be helpful for those interested in these details.

 

When most planking was done with natural lumber, double diagonal molding was the norm. With plywood now being more in vogue, the lapped seam, or Ashcroft, method is often used. It is often easier to get the desired compound hull shape with Ashcroft in plywood and it is just as strong.

 

Tom/guys, what is your opinion re a good approach to tackling the panelling
I.e. deciding on strip width, angle, grain direction, minimising material wastage?
A bit of initial trial and error and some broken wood?
These things would come with experience I guess.

Gonzo, I'm liking these tournament results for timber hulls. I think this is a good enough reason to stick with an all timber hull build
When you say the all glass builds don't feel the same, what do you mean?

 

It is hard to tell if it is just superstition. Maybe all the top fishermen believe it, so they keep on buying wooden boats and winning. Hard to say.

 

I've never bought into the Ford or Chevy debate, simply from a rational point of view and the same would apply here. Some seemingly intelligent argument could be made, but I just beat this very thought process, with a race boat I drew up a couple of years ago. Everyone swore their 'glass boats made for better and stiffer racers (30' - 750 HP) and the last 30 years of class champions proved this, though a few diehards (old guys) still ran their wooden boats. The son of one of these diehards had me design a new, wooden (double diagonal plywood) racer and her first season was undefeated, beating all the previous 'glass driving champions. I'm fairly sure this is the same thing in these tournaments, some good fishermen and some wannabe's that find something to blame, except the likely reality in their lack of success.

Lenm, your questions are pretty difficult to nail down, as we (okay maybe just me) don't really know what you're after. If you want planking speed, then molded Ashcroft plywood will be the best, pound for pound. Planking angles are really dependent on the hull shapes employed. You can offer a spec, but in reality it how the panels lay down on the jig that actually determines the angle. This angle will also change as the planking progresses, particularly along the very forward sections and possibly aft where a bilge turn can introduce a weird twist. The width of the panels will also change as required, with narrower ones forward and at tight bilge turns. Grain orientation is simple, it's longitudinal and preferably quarter sawn if solid wood. If it's plywood it's just grain long. Minimizing waste is just planning. Strip planking is very good in this regard, as the strips simply butt together, so long as neighboring butt joints are fairly well staggered, you can use pretty low grade stock and lots of butt joints. In this regard, you can build a lot of hull shell with very little waste and planking cost. This is an advantage of strip planking, though it's a tedious method.

 

Thanks Paul, I didn't know how to answer Lenm either. Thinking of some molded boats seen being put together, it seems that "it depends" is the best answer as the application will dictate the plank angle as well as plank width. Need for spiling also affect plank width a lot. One thing I do notice in professional yards is that waste ply isn't a major consideration when balanced against labor and supervision costs. Most just use a standard length as much as possible and let the ends run where they will. The workers can just lay the plies up without taking time to best conserve material. Most home builders will take that time and try to conserve expensive material.

Most builders using the Ashcroft method don't lay up laminate seams parallel. They do use some diagonal layup and the angle varies depending on what fits best with minimum spiling. Strength is the same in either case.