Help wtih boat bulkheads

Aloha All, I am designing a stich and glue canoe and have great results with RHINO. I plan on using my cnc router to cut out the panels for the canoe. I have used the section command to develop bulkheads for the canoe and now would like to create tabs that will protrude from the bulkhead through the side panels of the canoe. I would like to use these tabs and corresponding holes to refrence the hull of the canoe. How can I create the refrence holes in the canoe hull from the tabs in the bulkheads (if that makes sense?). Any help in this matter would be greatly appreciated.

Hi, if I understand correctly you’ve sliced a canoe shape to get the form of your bulkheads? If so, you’ll have to add the tabs to your slices, extrude them, then boolean difference (without deleting the original) from the hull skin. There’s a couple of ways of getting to the same result, somebody’ll be along with another solution.


also do the trimming like that so you dont have to sharpen those red lines

Also, my guess is, you will not want an exact fit - I’d make the objects that cut the holes slightly larger than the tabs rather than Boolean with the tabs directly.

That is exactly what I need to do!!! I tried the boolean difference but couldnt get it to work. Do I need to extrude the boat hull to the plywood thickness? then do the difference?

Do you want the holes to be round or shaped to fit the tabs? Should the holes be normal to the hull or aligned with the tabs?

rounded is fine. All it needs to be is a reference so that when I put the hull skins on the bulkheads all of the panels are referenced to each other. In fact, I think that a loose fit would be better than a tight fit. A loose fit would allow for some play in the panels to get a perfect fit between them. I have a file if anyone is interested in looking at what I got. I am sure my inexperience is the problem here.

send the file then.

and how do you plan to make tabs (pins) to be round from a bulkhead since you will use a plywood or something planar.

I plan on using plywoodstichandgluecanoe 9-15.3dm (146.3 KB)

i presume your model is outer skin of the hull, if it is, offsetting those surfaces inwards then placing your bulkheads would give you a better result otherwise your hull would be bigger than your model.

use “shift” of F8 while using section command your bulkhead curves are neither orthographic, continuous nor shares a direction pattern.

after offset is done with solid=yes you should make post to form hull, some of those will become bulkheads some of them will be removed

to be continue

That is awesome! Thanks for the f8 trick. I was getting very frustrated with my sections.
I will try now.

Also is it better to make sections on a surface?

Looking at your model, I can tell you that would work good as a pontoon, but as a single hull, it will fall over, and be very unstable. The main idea with “Stitch and Sew” is to use copper wire, twist tight, then fiberglass the seam. After the fiberglass sets, then you pull out the copper wire, and fill the holes with Epoxy. The Hull you have might work as a “Proa”, if you attach an “Ama”, then you could get some stability. Forget about having location pins, your working with wood, and the pins will offer no structural value.

I did these Renders fast but just to show that you really must make sure the beam is appropriate. Canoes have a flat bottom for a reason. High initial stability, then they flip right over, Multi-Chined boats are far more forgiving. My concept is in the middle, Same Length, just wider, a couple of more chines, thus more stability. I would investigate “Sharpie” style boats, and a boat called the "Windsprint’, Great and easy to build sailboats. :slight_smile:

The “wet” surface of the boat has vertical sides. This means when it leans over, it will fall. This is why boats widen, and ancient boats with tumblehomes were such failures, the could not take leaning well.


Cool idea but I am planning on iakos and an AMA. I am going to use this boat to fish an Try and surf. Most canoes here on the big island are round hulls and very expensive 6000$ +. That’s why I’m trying this in ply ( plus I learning rhino). I think this boat will work fine but it’s a first try and I’m sure I will build others. I like the pins for referencing all the panels so I can get things to go together easy. Mahalo for you input. This forum has been great.

Your making a Proa? I think these are fantastic, and if I new that my answer would be quite different,. You hull should a a sharp bottom, with sides flaring out in a fared curve to the deck. The entry into the water should also be fared, graceful to the beam of the main hull. Not sure if your making an Atlantic or Pacific Proa, but the principle is the same, the Ama will take all the force. If you need help, and post the .3dm file, and I will loft it for you.Sorry I took so long to answer, I just happened to log in and saw the reply, I received no notice. :slight_smile:

I have to add, if you intent is making sheets to trace on plywood, the only places this would matter is in the construction. You need to make the hull in a manner so when the ends come together, either you cut the ends so the meet on the appropriate angle, or, make a solid keel down the center, this would be the strongest method, and you could step your sail to the beam, rather than the deck, it would also allow you to beach it without damaging the hull. The beam, if extended a few inches, will make the boat track better too… This makes for a stronger boat. I have sailed in Blue water for many years, and to be honest, if you put that together with only bulkheads, I would go in nothing larger than a large pond with it. In the Ocean, it will eat that up. I have studied Proas for years. They are banned from racing in New England, so I never built one. They are banned because of their speed. You could stop and get a meal by the time the other sailboats caught up, and still win the race. That’s why they are banned, but I have seen Proas up here 40 feet long, and people live on them. Every single one I have ever seen has a keel, this is missing in your Renders :wink: