Building a fiberglass kayak--crazy idea?

[mike64]

I was reading an article about kayaks yesterday, and it mentioned the big range in price and quality-- on the low end is molded plastic-- heavy and slow but cheap. Fiberglass kayaks are on the higher end, light and fast but cost around $2500 new.

That got me to thinking, I've been reading the boat restoration threads here and glasswork doesn't sound too complicated if you're willing to work hard and get dirty. How difficult would it be to build a fiberglass kayak from scratch?

The main problem I can see is, the glasswork I've read about has all been either repairing a hole in a hull or glassing over wood. Making a glass kayak would require molding a hull just out of fiberglass. How is that done? Is a mold made out of something that fiberglass doesn't stick to, cloth and resin is applied and removed when it hardens? I imagine a hull and a cap would be made separately and joined, like a boat.

What about the cost of that amount of fiberglass? I have no idea. I'm thinking if it was doable it would be a cheap way to have a glass kayak, but maybe it would cost 2/3 of that $2500 just on materials. And should ANY wood be used for framing, or 100% glass?

Of course coming up with a good workable design would be as difficult as actually building it I bet.

So is this A) a crazy idea, B) not so crazy but almost as expensive as just buying a (used?) one, or C) a great summer project that would result in a cheap custom-built kayak?

 

[i386]

Re: Building a fiberglass kayak--crazy idea?

It's done by carving a solid block of styrofoam into the shape you want, glassing it, then hollowing out all the foam.

Are you wanting a whitewater kayak or touring?

 

[tommays]

Re: Building a fiberglass kayak--crazy idea?

Well i build my own bicycles because i ENJOY it NOT because i really saved ANY money (i think i really lost a lot ) i stoped because it was no longer fun


So the bottom line is the fun you get from the project, IMHP if your not willing to toss some mistakes in the trash as your build up your skills it will NOT work out

If you are and can treat it as FUN there is NOTHING better than building your own stuff

 

[mike64]

Re: Building a fiberglass kayak--crazy idea?

Okay, I got it. Kind of like in Kindergarten, putting paper mache on a balloon then popping it when the paper hardens (got a 5 year old). I guess everything you need to know you really DO learn in Kindergarten Thanks, i386!

No whitewater. There's a thousand little lakes around where I live-- it would be for the smaller lakes where a motor's not allowed, or slow-moving rivers. The article I read also talked about fishing from kayaks-- which I didn't think would be practical, but apparently is very doable. That would be cool-- to custom rig a kayak for fishing.

tommays, very true, but saving $$ would have to be some of the consideration, being married with 2 kids (she just got a new kitchen, but I have to negotiate for every dollar I spend on my hobbies )

 

[i386]

Re: Building a fiberglass kayak--crazy idea?

Ok...

Sounds like a fun project. Start by studying the hulls of touring kayaks. I am more familiar with whitewater kayaks but I know there are some very significant differences. Touring kayaks have little to no rocker as they are designed to be easily paddled in a straight line. Whitewater kayaks have a lot of rocker which makes them more maneuverable. Look inside kayaks too. They may have internal bracing which you'll want to duplicate. Some have fins and rudders that help steer or hold in a straight line. Make notes about the seat too. It's real important. Many have storage hatches so get some ideas how those are made.

I don't see any reason why you couldn't build a box, line it with plastic and fill it with 2 part foam, then break away the box. That'll give you a form to start carving on. You can form it with hand saws, surform tool, wood rasp, and dragon skin.

I don't think this would be cheap though. You might even end up building a few before you really got it right.

For a 10' kayak, you're probably looking at making a 40 cubic foot foam billet. That's going to run you over $200. (styrofoam may be easier to carve and dig out but won't be much cheaper) A gallon of epoxy resin is about $60. Guessing about $100 in fiberglass cloth. Since it's a boat, add all that up and multiply it by 3 to get a rough estimate.


There are several other construction methods you might try googling: strip, skin on frame, and stitch and glue. The "one off" method I was describing is called a foamie by some I think (similar to how surfboards are made).

 

[mike64]

Re: Building a fiberglass kayak--crazy idea?

Great tips, i386! From your cost speculation, sounds like I might spend about 1/2 the cost of a new glass kayak. Not bad. I'm starting to think seriously about this. It would be a good project for rainy weekends I can't take the motorboat out this summer. Plus would give me good glassing experience if I do any work to my old Saf-T-Mate next spring.

BTW, if anyone's interested, here's what got me thinking about this project-- actually 2 articles:

Kayaking 101
http://www.freep.com/apps/pbcs.dll/article?AID=2008805010412

You gotta love fishing from a kayak
http://www.freep.com/apps/pbcs.dll/article?AID=2008805010413

 

[i386]

Re: Building a fiberglass kayak--crazy idea?

Just thought of something else...

Lateral stability.

In kayaks, you have primary and secondary stability. They are a product of the hull shape.

Primary stability is the boat's resistance to listing from one side to the other.

Secondary stability is a resistance to flipping over once the boat has already listed to a point.


A whitewater kayak tips from side to side very easily. In fact, your hips are connected to the hull by pads. It lets you adjust the hull's lateral angle with your hips. If you tip the kayak to either side, at a point you will feel a resistance to going any further. It's like pushing on a spring. If you push to far though, it will flip. When you go past that point, the flipping is also spring like. You'll also have to overcome this force when rolling the kayak back up also. A good, non-beginner whitewater kayak will have low primary stability, but pretty good secondary stability.


In a flat water kayak, you want a lot of primary and secondary stability so that it doesn't flip in the first place. You don't want to try a no paddle, one-handed Eskimo roll with fish on the line in the other hand!

 

[mike64]

Re: Building a fiberglass kayak--crazy idea?

Sounds like you know your kayaks, i386. Where have you whitewater kayaked-- down yonder on the Chattahoochee?

No whitewater for me...I'd have to travel pretty far to find whitewater in any case. You're right, I'd want something with a lot of primary AND secondary stability. Weight's not even a big concern, as long as I could hoist it on top of my Jeep by myself.

 

[i386]

Re: Building a fiberglass kayak--crazy idea?

Sounds like you know your kayaks, i386. Where have you whitewater kayaked-- down yonder on the Chattahoochee?

No whitewater for me...I'd have to travel pretty far to find whitewater in any case. You're right, I'd want something with a lot of primary AND secondary stability. Weight's not even a big concern, as long as I could hoist it on top of my Jeep by myself.

I'm not an expert or anything. Just passing on some of the things I learned while I was into the sport.

Me and the wife have kayaked parts of the Chattahoochee and Cartecay in GA, Nantahala and Tuckaseegee rivers in NC. Nothing too big. Nantahala falls which is Class IV is probably the most difficult we've done. It's a lot of fun but we sold our gear years ago.

Fiberglass kayaks are LIGHT. That's why they make racing boats out of them. (High-end ones are actually Kevlar or carbon fiber) Roto-molded and blow-molded plastic kayaks are actually much more durable, impact resistant and abrasion resistant than composite hulls. They are also heavier. The machinery required to make plastic kayaks costs big bucks, but can turn out many boats in a day. Composite kayaks cost so much because they're hand made and can only be produced in small numbers at a time.

 

[oops!]

Re: Building a fiberglass kayak--crazy idea?

hi guys.....sorry to jump in here......

386 is correct on the mold design......carve it outta foam.....

however......the cost is higher than what was mentioned......

if you go epoxy.....approx $240 for a 5 gallon pail....you might need 3....

id suggest 2 layers of 1708...

you can do it with poly, at 120 for 5 gallons, but then go three layers of 1708.
you can do it for under $800, if you shop around for deals.......a good closed cell foam can also be had cheap.

 

[mike64]

Re: Building a fiberglass kayak--crazy idea?

Hey oops, how ya doing? I consulted your hull extension thread to see exactly how you made the extension when I first came up with this idea. Probably don't want to build a whole kayak out of arbourite though

I'm kind of rethinking this anyway-- kayaks are made out of molded fiberglass for lightness and speed, but I ain't going to be racing anybody. The main thing i want is strength and stability. It only has to be light enough for me to hoist it up on my Jeep by myself. Maybe glassed-in thin plywood would be the way to go. Or maybe mold the shell out of fiberglass and make the top out of ply. That would make it easier to build hatches for it.

 

[chicknwing]

Re: Building a fiberglass kayak--crazy idea?

I was at the library doing some research and came up with a book that may be of interest to you. It is titled "Devlin's Boat Building How to build any boat the stitch and glue way" the books ISBN number is 0-07-157990-7. May be worth a read just for some ideas on how they do it.

TC

 

[mike64]

Re: Building a fiberglass kayak--crazy idea?

Hey, nice find, Seaman Campbell. Looks like a good book-- and only $15 & change on Amazon. May very well buy it

 

[i386]

Re: Building a fiberglass kayak--crazy idea?

There's nothing wrong with a plastic Kayak. They're practically indestructible. A composite one is a Cadillac.

 

[oops!]

Re: Building a fiberglass kayak--crazy idea?

hi mike.....id forget the plywood.......just use glass....

but you might want a few ribs and bulkheads. (outta ply)

when i did the hull...one layer of 1708 and i could walk on it, 2 and i could jump on it, 3 layers and no worries.....using a bi ax, you will get stregnth and stiffness in many directions.

many new composite materials are avalable, like kevlar or graphite.

these are fantasticly strong materials, but graphite, will asorb water. after a few cycles of freeze/thaw. they become really brittle, and fail dramaticaly.

(think of a broken high tec hockey stick, graphite fishing rod, or a go fast tunnel boat. they literally disentergrate.

the arbourite wont do you any good unless your going over somthing.....id really try 386's foam.

ill be making my dash outta that. just carve it out if you mess up, glue another peice of foam on it, when done.......
glass it, gell it, then scrape away the foam.

i trust the 1708 so much for stregnth, im making my bench seats outta it. 3 layers, thats all.....(ill have a few wood supports under it in places)....and thats poly...!!!!.....if you use epoxy....it will be tough as nails.

depending on how gung ho you are....it could be done in a month.

this will be a fantastic project to watch

cheers
oops

 

[mike64]

Re: Building a fiberglass kayak--crazy idea?

this will be a fantastic project to watch

cheers
oops

Uh oh, looks like I'll actually have to follow thru now Me and my big mouth. :redface: I can't very well back out now that the great oops has weighed in! Oops, your hull extension project is one of my 3 favorite ongoing boat restoration threads, along with i386 and SgtMaj's '66 Woodson restoration (formerly known as "What am I about to get myself into")

I would like a good project like this, but I get these crazy ideas (note the thread title) and have little money and less time. At one point I had been thinking about building a small wooden skiff and fitting her with a trolling motor, but suprisingly my wife let me buy an old 16' runabout with a 60hp this spring. Working on that's going to keep me pretty occupied as it is.

If/when I do this, it sure ain't gonna be done in a month, though. If I worked on it that much my wife would divorce me (come to think of it then, I'd have a lot more time for working on it ... but a lot less money )

Question is, the stitch and glue book that Seaman Campbell recommended looks interesting, and I feel like I'd be a little less in the unknown making it out of wood. But oops and i386 have given a lot of great tips & advice on my original idea-- fiberglass. Wood or glass, that is the question.

 

[oops!]

Re: Building a fiberglass kayak--crazy idea?

mike if you hit search....

i remember a guy on here, that was building one....he had pics.....

it was a real nice job......he was from south on the equator if i remember.

i havent read the book that was suggested...but i know that the glass way with wood frames and stringers will be light, and strong.....once the form is carved....(that wont take long)....glassing will be easy....an hour a layup...

plus, with it at waist height, you can whip thru it.....really...can be glassed in two days......

the main reason the extension took me so long to do, was the legnth of the extension layups, i could'nt reach all of it to glass, so i had to wait to cure, so i could acess the other side, and because it was cured,,,,i had to ruff and scuff....

youd be able to do the layups and get a chemical bond, essentially forming one thick layer of glass.....really strong !

 

[mike64]

Re: Building a fiberglass kayak--crazy idea?

Yeah, I was wondering what was taking so long, oops. I mean, a simple everyday hull extension, c'mon!

What about a kayak with a glass body and a wood top? That way I think it would be easier to build a couple hatches into it. Or would that make it top heavy?

 

[oops!]

Re: Building a fiberglass kayak--crazy idea?

i would think it wood (joke get it ) be prone to building problems as the wood wants to remain flat....totally flat...you can bend it but it would be a pita.

glass is easer to mould and just as easy to cut hatches in.

but its your boat ! you can build it however you want...including a tiller if you want!

 

[arks]

Re: Building a fiberglass kayak--crazy idea?

Mike-
I've sea kayaked for about 6 years now. If you're serious about building one of these, look at kit boats because all the engineering has been done and the designs are proven. Remember, any boat design- especially with regard to kayaks- is a process that takes many trial-and-error attempts before getting everything right. Why spend your time and effort to make something that you probably won't be happy with (for whatever reason)?
Although I've never built one, I have paddled some kit boats. My favorite one is Chesapeake Light Craft (clcboats dot com). Exceptional engineered plans with every detail shown. Their boats are stitch-and-glue, look great when done, weigh less than a plastic boat, and perform like a composite boat. Their kits run from $800 to $1200 and include everything (except your time). As part of their kits they even offer free technical assistance by phone.

What about a kayak with a glass body and a wood top? That way I think it would be easier to build a couple hatches into it. Or would that make it top heavy?

The CLC boats are epoxy coated, which effectively seals them like fiberglass. I paddled with someone a couple years ago who built a CLC kayak and made the hull with real carbon fiber (NICE, but super expensive). That was the most beautiful boat I've ever seen....
Whatever you decide, good luck. I wish I had the time to build something like this!