First timer question

Good afternoon,

Long time lurker here and have a question. I have a Pacific City Dory (flat bottom surf launch) that I fish off the Oregon coast and have had the interest in building my own.

I have drawn up several sketches of what I would like the end product to look like and was curious if there was anyone here that can create CAD drawings that could yield precut frames/components to minimize build time as well as maintain symmetry.

Thanks

 

Welcome to the forum.
Besides the CAD files, do you need someone to check if the boat is stable, sturdy, has sufficient buoyancy, and other such nonsense?.

 

Thanks for the response.

If those other data points were easily discernible via design software I would be interested, but the lamination schedule I have in mind relative to the ply over frame design I wish to make a hybrid of, I feel fairly confident I can achieve proper balance and structural strength particularly when coupled with cold mold construction.

The inspiration is coming from a wood cored glass boat that I currently own and has not been In production for 40 years. Plan is to stretch by a foot and widen 6” and a few other modifications to enhance fishability.

 

The 4-part developed hull (bottom, sides, transom) is pretty easy from accurate 2D views, the scantlings and the 'other such nonsense' would need some consideration for the way they are launched, piloted, and landed.

 

Launching and landing is where the abuse takes place. They are launched through the breakers and landed on the beach. As I mentioned the boat I am currently running has a bottom consisting of sandwiched balsa, thin glass sides and 2x stingers running fore and aft. Glass is a mixture of cloth and chop.

My theory is if I can use a solid ply bottom (2 layers of 3/8” ply) with 6 layers of 1700 below 3 layers of cold molded 1/8” ply sides (with multiple layers of 1700) the resulting structure will be more buoyant than my current boat and stronger

 

My understanding is that structure being more buoyant in this case only comes into play if the boat is capsized. Otherwise a heavier built hull about the same size just sits lower in the water and has reduced payload capacity at its max load line.

 

Let’s see those sketches!

Everything is speculation otherwise.

For your bottom, I would not use db1700 as the final layer. It is ‘structural’ glass, very strong, but the fibers are not designed for beach wear, not to he confused with bikinis (drifting off). I would recommend the last layer to be csm out facing 1708, or just a layer of csm. The fiber orientations are all over and it will perform better on wear through (super ez to repair on a bad blow thru, too). A better idea still is using white pigment resin in the last layer of db1700, then the csm layer (equal to 1708), then paint with graphite impregnated epoxy (3 coats). If you see white; you know you must repair the black graphite layer before damaging structural skins this way (because you know you will blow thru).

ps ~ if it were my boat, I’d probably use two layers of 1708 for the bottom, csm out, or perhaps 1700 first and 1708 csm out 2nd (saves one pound per sq yd to use the 1700) you already have lotsa strength and stiffness in the plywood

 

Thanks. Your thoughts around 1708 make sense. My only reasoning for the 1700 was it would be less thirsty for epoxy and also dismissed CSM due to its incompatibility with epoxy resin. 1708 would be a good way to bulk the bottom. I actually know of a gentleman that recoated the bottom of his glass dory with epoxy loaded with graphite and have been told it works quite well. Some other dorymen have started coating their hull bottoms with a product called Wetlander which I believe is a siliconized epoxy—this is used on the aluminum boats to aid in sliding on the sand and works quite well.

I have attached photos of the popular wood design built by Terry Learned as well as newer ones fabricated out of aluminum.

The wood boats were covered with roughly 1/4” of chopper glass on the exterior and oil finished inside. I believe this was done with poly resin and would not offer any additional structural strength.

The general design has been left relatively unchanged since the early 70’s and all seem to follow the original ply over frame lines.

Cold mold construction should allow for fewer transverse frames (thinking every 4’ including bulkheads and tabbed in), add flare midship forward for a drier ride along with a number of other modifications that are not practical on ply over plank lines.

Rough draft added. Pretty rough…goal is to change shear line, maintain inside freeboard

 

CSM isn't such a bad material. In my own boat, 3/16" CSM caps over the plywood floors and keel kept the 400# iron keel from kissing the driveway long after the plywood rotted. There were 4 floors and the hull did not move with the keel load until the 3rd cap was cut. I ran this through laminate design software and realized I would need 3 layers of 1708 to replace the CSM that was removed instead of the 2 recommended and that some of the layers would need to be 0/90 instead of 45/-45 to make it more or less equal to previous.
It also comes epoxy-compatible, in its own rolls or part of 1708.
Your supplier should be able to comment if the mat products have a styrenated binder (better with polyester resin) or not.

When you are ready to show more of the sketches, you may want to run them through a copier and email yourself the images first or be careful with the phone so that the grids on the paper are square and not distorted (flat view: no perspective, skew, barrel, or pincushion).

 

In a much lighter environment, graphite loaded epoxy is my go to bottom coating on canoes and small sailing proas. It's easy to maintain and helps slide off the occasional unintended contact with rocky banks without damaging the hull.

 

I really think you need to find a plan. That is a lot more boat than I expected, ito length. A plan will be worth the effort tracking down. I’m surprised you want something as large for surf fishing, but perhaps I don’t understand the use case well.

 

Surf launching and retrieval, needs some updating https://www.boatdesign.net/threads/surf-launching-and-retrieval-needs-some-updating.51270/

 

Colin Tolman - Standard Tolman Skiff - TolmanSkiffs.net https://tolmanskiffs.net/colin-tolman-standard-tolman-skiff/

 

Yes that’s what I’m after. The only plan that exists is the Glen L dory plans, which are ply over frame—I believe the red boat first pictured in the thread you attached is or is some kind of iteration of the Glen L Hunky Dory if it’s the boat I’m thinking of.

I’ve combed the web looking for plans and after seeing some of the resources available on Boat Builder Central and perusing the Gougeon Brothers book, I’m half tempted to run with the concept and see what I can create.

 

The flat bottomed Tolman is a superb choice. I asked Colin from Tolman to reply here if there is a true flat bottom. I think the one I linked has some vee, but they discussed the originals as flat.