Repair of a broken kayak?

Hi Guys,

First of all, sorry for my English.

I need help and advice as many of you seem very experienced in composite boat building and repair.

I could buy the kayak on the attached pictures for approx 350$. It has never been used (saved from a sunk ship by a diver) but its hull is damaged and there are some other minor issues with it (steering) in addition. It has been stored on the concrete yard for about a year.

Actually my question is if it is worth it to buy? If I bought it I would try to repair it myself but I have no experience in that kind of job. I built something from fiberglass and epoxy 7 years ago but it was not a boat.
What is the process of a repair like this? What material do I need? (in addition to fiberglass, epoxy (or polyesther?) resin and gel coat.
What tools do I need?
What are the work steps and what is especially needed to take care on?

Thus I would like to ask for (detailed) instructions, advices and everything that can be use- and helpful.

Greetings,
TiGer

from Norway

 

The kayak is probably not a good deal if you counted every hour you will spend repairing it but...
The price is right and my guess is you'll spend another $50-100 to make it perfect. It could be done for much less if you already had purchased bulk supplies for use with other boats, but of course you'll have to buy whole containers of epoxy, etc., to do the job.
Your labor can't be counted as worth much at all since you will take a lot of time to do the job right. Of course, if you enjoy (or can use) the experience, then it's definitely worth it.

 

If you are looking at learning how to work with fiberglass, this can be a good project. However, It will probably take you 20-30 hours plus whatever time you spend on research. The materials won't be much, but for a broken kayak the price is very high. It should be less than $50

 

Thanks for the replies. I don't count the hours I might spend on it since I would do it in my free time and I enjoy manual work. (I work in an office.)

I found a quite good video on Youtube how to repair fiberglass: http://www.youtube.com/watch?v=SsoKAHU5xUw

This technique could be used here, couldn't? What is your opinion? There is access to the inner surface through the lid but it would be much more comfortable to remove the yellow top half. Is it possible or not?

Another problem is that the crack goes through the whole hull so it should be cut into two halves actually. I would rather repair one side first (left or right) and the other afterwards. Then the hull would never be in two pieces. What do you think about this?

 

The video isn't very helpful in your situation, as it's just a cosmetic repair type of thing. You've got some structural considerations to consider.

The first thing to do is see how badly out of shape the damage has made the boat. Eyeball the keel line and see if there's a kink. This will be the best indication of a major issue. If there's a kink the boat needs to be braced back into position, so any repairs can hold her in the shape she needs to be.

The way to repair her is with epoxy, not polyester. Epoxy is better suited for a number of reasons, but mostly because it's much more novice friendly and considerably stronger too.

Grind the damaged areas back to solid, good fabric. Since it's Kevlar, this will eat up sanding materials and make a difficult to fair surface, but it has to be done. Taper all the edges on the damaged areas, inside and out for at least 100 mm. This taper will provide a place for the filler materials and new fabrics to live, without a bulge.

With the damaged areas aligned and braced into position, wet out all the areas with straight epoxy, then apply your fabrics. I'd recommend a 45/45 biax 'glass cloth rather then more Kevlar, as it's much easier to work. At least 2 layers of 400 GPM biax bridging the cracks and holes, stagger any seams or use butt joints on the first layer and overlap these on the second.

When this gets slightly tacky, apply an epoxy fillet mixture, of milled fibers and silica over the areas you just laid fabric on. Make this as smooth as you can and feather into surrounding areas. Let all this cure for a day or two, then start fairing smooth, in preparation for paint.

The is the abridged version of the repair. Log onto www.westsystem.com and www.systemthree.com and download their user's guides for tips, tricks and techniques on this type of thing. It's not hard, though you'll be really tired of sanding when it's through. Just read up on the techniques and material choices and you'll be better armed to tackle this project.

 

What brand?

I have a carbon/Kevlar VCP boat and it is one pricy machine:

http://www.valleyseakayaks.com/content/boats/composite/avocet

I suppose the purchase price floats a bit on the pedigree eh?

I would not think twice for a hundred or so and having all the gear I would bang out the repair in a few hours work, then give the boat to a friend or such.
One trick is to bond down some battens (read paint sticks) over the repair area on the inside, grind out and do the glass work outside. The pull the battens and do the inside work.

I would do careful deep tapers on outside, then shallower work inside with the last bit of glass carried out over as below:

 

Hi PAR,

Thanks a lot for the detailed instructions. But what is the difference between the video and your version? Just because they also grinded out the damaged area and tapered the edges similar to your advice. (only from one side, is this the main difference?)

So the top layer (gelcoat) will come after the layers (an top filler) had been built up, is that correct? This final part was a bit unclear to me. I have a look at the sites you mentioned.

Is my "what to do - drawing" correct?

One more question: are you sure this is a kevlar boat? I think it is fiberglass. It's original price is around 2000 USD in Norway.

TiGer

 

bntii

What brand? This what I'm trying to find out now. I might be able to answer it tomorrow.

Thanks for the tips.

 

Better yet, to support better than battens and no bonding issues- perhaps spring in a piece of 3 mil ply to keep the skin in alignment while you do the glass work:



The ply has a piece of plastic film to keep it from bonding to the hull during the outside repairs (the blue layer).
The ply is held to the hull with braces to the top deck.

 

A plywood backer is a good idea at first blush, but this assumes you're working with developed surfaces, which I'll bet aren't. Strips of plywood on a bias would work. I think this may be more trouble then necessary on this repair.

TiGer, your drawing is basically correct. You're not going to gel coat this repair after it's done, but paint it instead. Why? Well, simply put a novice attempting to gel coat, with a reasonable finish and color match is just not very likely, to have much success.

Besides, it needs a new color scheme anyway, right? I don't know what the hull material is, but 'glass would be the logical material. I don't know where I got the Kevlar idea from.

 

Hmmm- I'll top that with the length of light ply backer needed will suit the repair & not need or take the slight compound bend.
Looking at the hull form again, P&S backers will be needed about the v of the keel- the OP will work it out no doubt..

My first blush ideal would do though: simple paint stick battens, but I am betting that a quick backer of luan ply will spring in and do the deed.

How is FL Par?- I checked on the Robb, it was not yours though the current owners remain overwhelmed by the job... glass the hull and be done with it eh?

Regards

 

Damn, I was hoping she was, it would have been nice to see the old lass again.

Florida is typical sunshine state. this winter was the warmest on record, not a drop in rain for months, then a couple of down pours in the last few days. Maybe the rainy seasons will kick in a couple of months early. Tonight pleasantly cool in the mid 50's, tomorrow high in the mid 70's low humidity. Tuesday, more of the same, but by mid week more summer like weather, in the low 80's and higher humidity.

 

its a major and will take a bit of work to get it right again !! I would start and do the outside first then once glassed then do the inside . The damaged areas show up the weakness of the hull , sure its had a good old pounding but even so its not that strong , Me i would be using undirectionall glass but if if you have neve done repairs before double bias would be the next best choice !. use a good quality epoxy resin for all your repairs . You have some work to do with a grinder and a medium to fine disc and very gently scuff and grind and feather the damaged areas 50 to 100 mm around all damaged areas so the new glass will have a really good bond to the old surface !! glass them and when all is hard turn the Canoe over and do the same with the inside . The damaged glass needs to be completely ground out untill you are back into the good glass again .
Keeping the canoe light is a bit of problem as the best cover for the whole of the bottm would be Kevlar as its robust , and much better abrasive resistant and will take much more hard pounding and bashing against rocks etc etc choose your materials carefully and take extra care doing your repairs !!

 

bntii, Par,

It is clear that I need some kind of backer since as I looak at the pictures I need to grind out 10-15 cm wide pieces. Ply strips seem good to me. bntii, you write "P&S backers will be needed" - what is P&S? Paint stick?

Par

If I`m right I should paint the top filler resin directly. But what is the original top layer of the hull? Gelcoat? If so, do I need to sand and repaint the whole hull or only around the damaged and repaired area? If I painted it, is there a primer + paint + top lack or just paint + lack or paint only?
On the photos you can see areas where the top layer is cracked but the fiberglass may be undamaged. What to do there? Only sand and paint or do I need to grind it out too?
I had a quick look at the westsystem guides yesterday, they are very-very good, I will learn a lot from them.

Now I am quite clear what to do (except the questions above ), thanks guys for the help. There is a bit more work with the boat than I expected so I`m trying to beat down the price to the half and I might buy it then. It would be a good experience.

 

Good morning Tiger- P&S= port and starboard.

I was just commenting on the presence of a 'V' shape in the hull not shown in my second drawing. This indicates to my mind that the approach will have some sort of sheet backer or battens which are placed on each side of the hull.

I think you have the ideal- a backer(s) of some type is likely needed to keep alignment of the hull shell as the repair is done.

You might want to start by assessing if the hull is still fair as par mentioned in his first post.
This finding will direct how you approach the backer question.
Also- springing in a batten may be needed to shift a deformed section of panel out/into alignment, while simply bonding down may have more utility if the form is correct as she lies.
The rigidity and length of the battens used will have a bearing on how much of hull form is carried from adjacent panel over the repair area- to rigid and a flat spot is created, too limp and the hull may have a bulge at the repair.

There are many tricks one can employ such as tape pulled tight over the hull as a bonded in batten cures.
The goal is all the same- hold the hull fair and tapers aligned as the outside glass work is done.

You will have to suss it out as you go just keeping in mind the issues that need addressing so that you end up with a credible repair.