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Hull Design Ideas


I’ve been noodling around with the idea to create a autonomous boat, using BlueRobotics thrusters, of course. Through that I’ve been researching ideas on what and how to make the hull. I thought I would capture those materials and thoughts and design ideas here. Please feel free to critique and add to these ideas. I’d love to hear input from your research and from those that have constructed hulls and can give tips.

The ideas below are some of mine and some already listed here on the forums. I’m thinking mostly catamaran, but capturing all sorts of ideas. Please contribute.


Child Size Kayak :: around 5 or 6 feet in length. Good for a monohull construction. Fairly accessible and low price too.

Kayak Caddy :: http://kayakkaddy.com Could be a cool mono hull or wide catamaran style.

PVC Pipe :: for a catamaran or trimaran, PVC or CPVC could be used. Schedule 40, since it is lighter. I recently came across PVC pipe for HVAC ducting, and that may be a thinner wall. The pipe probably will need painting since PVC will break down in the sun, CPVC won’t. The fittings give all sorts of options for the bow and stern of the pipe (flat cap, 45 degree bend, etc), however it may be not a smooth surface because of the lip of the fittings. Could be inexpensive for some quick testing.

Floats :: using fish/crab trap foam float or buoys is an option. They may have to be rigged into a pontoon of some sorts. There are some 14" x 6" diameter crab trap float I saw on Amazon that others have repurposed as an outrigger for kayaks of canoes. https://www.amazon.com/KUFA-Sports-6x14-Inch-Float-2-Pack/dp/B00HXD4RRO/ref=sr_1_4?ie=UTF8&qid=1470699157&sr=8-4&keywords=crab+trap+float

Foam :: Get the right kind of foam (closed cell) in large blocks or sheet and carve your own hull or pontoon.

Fiberglass or Carbon Fiber :: perhaps an extreme DIY step, but fun in learning none the less. With this option one can craft the hull shape just as they want. It may take a bit of work to do the layers and layup, but the results should look stunning. The mould could be custom made, or maybe it is fiberglass or carbon fiber over the PVC or foam floats.

Canoe or Kayak Outrigger :: As proposed in this forum, there may be some other outrigger or support that are made for canoes and kayaks that could work. I like several options I’ve seen in this area. The best options though seem to be overseas and I haven’t taken the time to look for USA distributors.

Expandacraft :: http://expandacraft.com I came across these some time ago. It looks like various universities have used these. Simple, can be broken down to fit in a car. However the price is a bit much at US$550 for a set.

Aluminum pontoons :: I don’t remember where I saw it, but I did seem some small aluminum pontoons somewhere online. They were in the four foot size.

Sheet goods :: using PVC sheets or wood sheets and constructing the hulls. This also requires various DIY techniques for sealing and ensuring a good float is made.

(Paul) #2

If this is your first UUV (autonomous boat) build, I would recommend you go cheap and plan on transferring your electronics and thrusters to a better platform at a later date. There’s a lot of experimentation involved in the process, the boat is really just part of it and chances are your perspective on your needs will change once you’ve started building.

For this reason I like Kevin’s recommendation, the child’s kayak. Not an ideal platform, but for under $100 you can’t even build a boat that size for any less.

What kayak outriggers were you looking at that were from outside the US? The one’s I linked to were from Minnesota.


Paul - I agree about the boat needs changing once I get into it so it is best to just get something easy. I should sit down and write out the goals for something like this as that would direct where my attention should go and therefore my time, effort and cash.

Thank you too for the search terms provided earlier, there have been many items I’ve looked through regarding stabilizer and outriggers and that has led me down a rabbit hole.

Here is one float I found, it is in Australia.http://www.kayakshopaustralia.com.au/aquayak-kayak-stabiliser-float/

I like this one too from France. What I like is the attachment method on the ‘pontoon’. Looks like some dealers in the USA, but needs more sleuthing. http://www.rtm-fishing.com/en/accessoires/k-largo-abaco-stabilizer-kit/

This the one you linked to. Do you know the size of this? I’m not seeing dimensions but would guess 3 feet long. http://store.springcreek.com/Stabilizer-Floats-for-Canoes-and-Kayaks/Canoe-Stabilizer-Floats/Spring-Creek-Replacement-Stabilizer-Float-Hydrodynamic-HD-p1686.html

(Kevin) #4

Dave Boulanger (DIY Drones and Ardupilot Forums) had a pretty good one out of sheet wood: http://diydrones.com/group/arduboat-user-group/forum/topics/arduboat-built-from-scratch-is-almost-ready-to-go

(Spally) #5

Tim, have you checked out DIY Drones? there are plenty of different ideas on there regarding hulls. I agree with Paul and go cheap and then transfer all your gear to a better hull later.

Here is an option. http://www.horizonhobby.com/1-5-scale-float-set-han6030 Ditch the upper supports and you have a 1m long cat.

I have gone down the Carbon Fibre path with my hull. I run twin T200’s with vector mounts for steering. I get about 45deg either side of centre and my boat turns on its own length. With a commercial grade sounder, dual beam transducer, GNSS Receiver and batteries, my boat is running around with 20kg of equipment on it. With all that weight, the boat runs nicely at just over 4kph. The system is 12V so that normally runs at 14Amps which gives me over 4hrs runtime. My boat is 1200mm x 600mm in size and is very stable. Are you wanting a platform just to muck around with navigation or do you want to do sounding/mapping?



(Paul) #6

@Spally - What’s the maximum depth of water you are able to survey with that system and what sonar are you using?

(Spally) #7

@Paul - I use the CEE Hydrosystems (http://www.ceehydrosystems.com) products. I can squeeze in the CEE Echo and a Airmar Dual Frequency EchoRange M195 transducer into my boat. Here is a photo. The range is dependent on the water but they say 200m, way above what I would ever use. That is reduced because I use a wet well (The big grey bit with the black transducer cable coming out of it). This holds the transducer and water and the unit transmits through the hull. This keeps the outside clean and away from the harsh chemicals that are in Tailings Dams. This was built for Mine site dams where the water isn’t the best and people are not allowed onto the water with real boats. I thought a generic sounder would do the job but after seeing what is capable with these units and issues people have with validating the data, my customers want these dual beam units.

The photo shows the fitout with the M163 transducer. As you can see, it is all a tight fit. The M195 give me a fair bit more room and reduced weight.


Thank you for the further encouragement to go inexpensive at first. It sure helps to write things out and get others to comment.

For the HD floats that Paul recommended, I found this link: https://www.sailboatstogo.com/content/HD_floats and they state that, “42 inches long by 6 inches at its fattest point. It’s hollow. Material is a high-impact plastic. Weight: 4 lbs. per float. That is bigger than I thought and would work.

I also found Banks Boards while doing another rabbit hole search. http://www.banksboard.com/purchase.html A 44" by 24" hull with all sorts of molded in attachment methods for accessories that scuba divers would want to add (or those wanting to attach equipment for making it an autonomous boat). It is US$250.

I’ll read though DIY Drones, thank you for that link and the Horizon Hobby option too.

I really like your set up Spally! I remember seeing this a year or two ago when I first started Googling on this subject. Your thrusters are cool and the size of your boat is just right, in my opinion. For now I’m just mucking around though at one point I was thinking about mapping so maybe someday I explore that possibility. If I recall right your hull is completely custom too? I was hoping back when I first saw your design the hull was off the shelf.

(Paul) #9

@Spally - Very nicely done and thanks for the information.

@Tim - Your “google-foo” is amazing, where did you find these things? LOL

(Spally) #10

@Tim - if you are interested in just a hull with no fit out, email me.

jspall at crkennedy.com.au


(Kevin) #11

Those Banks Boards are legit and gave me a few ideas for a USV 03 prototype. Not much freeboard, but looks pretty stable.


I really like the molded in attachment points on the Bank Boards and figure they have to be stable and strong in their main application. How do you think you would mount thrusters to the Bank Board? Would you mod the board in some way or bolt on bracketing to the existing mounts? I was thinking bolt-on just to preserve the hull integrity (and if I wanted to repurpose the board for something else in the future I could).

(Kevin) #13

If you can figure out a way to bolt on the thrusters, that I think is the way to go, however, the attachment points look pretty weak. I strongly recommend maintaining hull integrity.

If you don’t mind some cutting and epoxy, make up some appropriate mounts out of HDPE and glue those to the underside. It’s what I do instead of drilling holes. Just be aware that you will need to roughen both contact points pretty well and even at that point, if you hit them hard enough they will pop off. Easy fix, just annoying.

(Paul) #14

@Kevin - I wonder if 3M 5200 might work better than epoxy for your application? Seems to stick pretty aggressively with everything I’ve tried so far.


Here are some more ideas or perhaps mixing up the ingredients of ideas already posted.

I rather like this high density polypropylene foam roller. https://www.amazon.com/PE-Roller-Black-Made-²CFH8Z/dp/B00YLZPXHK/ref=sr_1_75?s=sporting-goods&ie=UTF8&qid=1470528726&sr=1-75-spons&keywords=6%22+foam+float&psc=1 I wonder what the buoyancy would be. The roller is 6" diameter and come in various lengths. This could be used straight up as a float or pontoon or it could be coated with fiber glass or carbon fiber. One could shape the front and back for the desired profile.

If you wanted some big profile than the 6" diameter, one could buy sheets of the foam, glue it together and then carve the shape.

I also like this image, kind of small res, but enough to give an idea of the setup.


This image was one of the ones that provoked me to do more searching for paddle boards, wakeboard, body boards, etc. that lead me to the Banks Board. I feel I still have searching to do there, though I really like the Banks Board. For this picture I suspect the pontoons are custom. I like low profile. I suspect the pontoon are easily detached for transportation.

Of course a high end solution would be designing your own hull profile and CNC carving or cutting the parts to assemble. Or going uber high end is doing something with Proto labs to fabricate it. If there was a project with the community to design the equivalent float/pontoon to a Banks Board, I’d consider jumping with a preorder and design thoughts. However I don’t have plastics specific design experience.

I like the Horizon Hobby boat float/pontoons too, I hadn’t considered that. Thank you for adding that to the list.

(Paul) #16

My wife has one of those PE rollers (Poly Ethylene - same material as used in “pool noodles”), she uses it for her yoga class. I don’t think it would be a suitable base for fiberglass / carbon fiber. If you want a cheap foam for fiberglass construction, look at the sheet foam sold for home insulating. It’s rather weak / low density but has been used by others with some success.


Many more ideas flowing through my head, many of them variations on what was stated before. One link I thought I would share is below. They look relatively new to the scene. I like that they have the thruster mount already designed into the hull.


(Kon Pagonidis) #18

Hi you can use a Bait Boat From bait boats lakes entrance aprox. 1000mm long . they go for $ 250 Plus Del. contact 0419870677 , or remopwatercraft@gmail.com


I found the thread while looking for something similar. I am also a newbie in autonomous boats, though plenty of experience with coding, embedded systems etc. So I want to play an experiment a bit. I don’t have a huge budget, especially considering everything I will lose and damage along the way :slight_smile:

I found two candidates for my use:

Any recommendations for or against them?

Thanks in advance