Fibreglass keel repair on trailer

I have the usual gelcoat scrapes along the keel, fairly bad and right through to the weave in many places. Early on in the boats makeover I turned it upside down in the garden and spent lots of time grinding and filling with a gelcoat repair kit. However after only about 8 hours or so use it seems much of it has come back off and I'm now feeling I need to do something more substantial.

The boat takes on very little water, if any. couple of gallons for a full day's wakeboarding so I don't think it is leaking.

I have plenty of chopstrand and Biax cloth offcuts as well as a couple of litres of Poly Resin that I picked up from a boat builder.

The question is, can I glass upside down with the materials that I have, and if so, have you got any tips....

I cant really turn the boat over now it's finished and I am really reluctant to cut holes in the deck to get from the inside.

Re: Fibreglass keel repair on trailer

if there is holes in the boat....they must be inside out repairs.

if its the keel scrapes you are fixing.....just mix a "hot batch "with the csm......then when really tacky....use the bi ax.....cover with another layer of csm.....then a finixhing veil of roving......fair....sand and paint

Re: Fibreglass keel repair on trailer

Thanks for that, I may sound stupid but just need to clarify a few things.

1st, Im sure it's not holed right through as I said it takes on no water, think it was just my bad gelcoat repair coming of through beaching.

then what is "hot batch"? what is roving? and how do I mix the csm with it?

Do you mean wet the hull with resin then csm, then resin over?
Or do you mean pre-wet the csm and put straight on?

Re: Fibreglass keel repair on trailer

Ok been pretty much sat on the net all day trying to research this but nobody seems to have any direct info on glassing upside down.

Sorry if I'm a bit slow but bear with me.... I gathered Opps just meant mix the resin and catalyst when he said "hot mix". I was thinking that it could be too 'runny' to put on upside down and would not hold the csm/cloth without sagging, but it seems this is the only way?

I have a couple of pics just so you know what materials and damage I am talking about. Please don't laugh at my previous gelcoat attempts, I had not discovered iboats at that point and was even more green than I am now!

Would you buy a grooved roller for this? or use a squeegie?

http://i497.photobucket.com/albums/rr333/kiwigt/IMG_2087.jpg
http://i497.photobucket.com/albums/rr333/kiwigt/IMG_2088.jpg
http://i497.photobucket.com/albums/rr333/kiwigt/IMG_2086.jpg
http://i497.photobucket.com/albums/rr333/kiwigt/IMG_2085-1.jpg

Re: Fibreglass keel repair on trailer

I'm not real sure about the repair job but it won't matter if you don't stop dragging that poor hull across the rocks...... beaching is hard on gel coat. You can use a keel guard to ease it some but it looks like the damage is far wider than the guard


Now my best guess on the repair is...... 86 the cloth, roving. matt, and such. Sand agressively to get a clean uniform surface. apply gelcoat and cover with plastic wrap so it will cure. Then remove wrap and sand smooth with progressively finer grit until you can buff and wax..... you need to get it off the trailer and on some stands so that you can get to the bottom and have room to work...... I suspect that this is a far bigger job than you think it is.

Re: Fibreglass keel repair on trailer

smokeonthewater said:

I'm not real sure about the repair job but it won't matter if you don't stop dragging that poor hull across the rocks...... beaching is hard on gel coat. You can use a keel guard to ease it some but it looks like the damage is far wider than the guard


Now my best guess on the repair is...... 86 the cloth, roving. matt, and such. Sand agressively to get a clean uniform surface. apply gelcoat and cover with plastic wrap so it will cure. Then remove wrap and sand smooth with progressively finer grit until you can buff and wax..... you need to get it off the trailer and on some stands so that you can get to the bottom and have room to work...... I suspect that this is a far bigger job than you think it is.

Click to expand...

Not trying to pass the buck as such.... but the damage was done way before I ever got near it. I do beach the boat yeah, but not too often and only on fine sand, not rocks/pebbles etc.

My mistake was not spending anywhere near enough time on the gelcoat repair the 1st time when the boat was upside down and it was easy. Oh well, you live n learn i guess.

Anyway, I still do want to put a few extra layers of glass on the two real warn sections (in the pics) just because I expect the original glass has warn so thin it would be susceptible to further damage in the future.

AND yes you are right, I am starting to think it is gonna be a more difficult job than I first anticipated. The thing is though this boat was only ever a 1st project, a cheap fun thing to start and learn on. I will probably look at selling it at the end of the season and buying an inboard more suitable to our needs. Therefore I don't want to spend huge amounts of time and money on it, and don't really care cosmetically either. Just wanna make sure it floats, runs, is safe, and we get as much time on the water as possible to use it this year.....

Re: Fibreglass keel repair on trailer

Bubba1235 said:

One caution, you MUST get the fiberglass COMPLETELY dried out before you apply the new glass and gel coat. If you don't, it won't last a season. (It usually means using a lot of dry heat to accomplish.)

Click to expand...

Any tips for doing this?? I don't have a garage that I can use, but the boat is in a car port sheltered from the weather to some extent. As you can see last week I made a start on sanding off the old gelcoat to allow the glass to dry and tilted the boat up as much as poss so it does get a little sun on it. Would a heat gun be sufficient if I sit there for a couple hours a day for a week?

As I said before I only really intent to keep it for the season so If I leave it for 3 months to dry it will kinda defeat the point. I have a week off work, then I am moving house!! so I wanted to try n get the bulk of the work done before then.

I guess the other option is just ignore the problem, use the boat for the next couple months till winter, then get rid. I just felt that I should at least make some attempt to seal up the exposed glass.

Re: Fibreglass keel repair on trailer

Cool, thanks for the advice, I will look into all that and make a start tomorrow, hopefully I will have something to show for it by the end of the week, I'll get back to you with the results.

I actually think in this case it will be easier on the trailer. I can tilt the boat right back and put blocks under the stern and as the damage is under the bow it gives me enough room to actually sit under the boat on a chair to work. Also it lifts the damaged area to about 45degreez instead of 90degreex upside down so should make it a little easier to work without sagging. and by luck the damage I wanna fix is right between the cross members so they are out of the way.

Thanks again

Re: Fibreglass keel repair on trailer

how much is actually worn off? I didn't see anything that looked anywhere near needing rebuilt.... the keel is likely over an inch thick so even a 1/4" gouge really won't have any effect on strength.... I would just sand and gel it..... unless there is actually major damage

Re: Fibreglass keel repair on trailer

OK, Iknow this is a pretty old thread now but Ithought I would come back and finish what I started.




I went with doing the glass repair in the end (the bit I thought would be difficult).-

fully dried out the existing glass, cut out a 'bowl' for the new glass to sit in, clened up with Acytone, cut csm to shape, wet it out on wax paper and presed it onto the hull and rollered out the bubbles. Waited for it to get tacky and repeated with 3 layers of csm and 1 layer biaxial. Sanded it all smooth Job finished!! This part all went smoothly and easily and was done in half day all together.

Then the gelcoat (the bit I thought would be easy) has taken a hugeamount of work and hours. In the end I decided to re gelcoat the whole keel plus any other chips I could find. This meant doing all the sections I could reach between the rollers, waiting for it to set, then moving the boat on the trailer to do the bits in between and blending in the sander.

To cut a long story short I finished it in the end, from a distance the hull now looks mint, up close not so much, but hey it was a cheap fix and it's a well used 40 year old hull, it's never gonna be perfect. Im happy with it, it's been out several times since and is showing no signs of damage or wear.

Gelcoat seems to be a messy awkward horrible substance to work with and learned alot on the way. If i were to do it again it would take a quarter of the time.

Re: Fibreglass keel repair on trailer

It only has to look good from 5 feet away and if you put a keelguard on it it won't show anyway. But it looks like you did a good job.

Thanks for updating this thread. I have to do a similar repair on my boat so it is very helpful to hear how this method worked for you.

Re: Fibreglass keel repair on trailer

Cheers, like I said I'm happy with it, considering it cost the price of gelcoat and brushes - maybe $20 all up.

I did look into keelguards, but the cheapest I can find is $75 per foot, so it's gonna cost $500+ just to do the minimum really. I love livig in NZ but this country is just so dam expensive for everything. You guys seem to get everything so cheap in the US.

Re: Fibreglass keel repair on trailer

Nice thread. I'm going to have to do some similar repairs to my boat since I grounded it on some rocks this weekend. Scraped away the gelcoat on the keel down to the fiberglass, and even gouged the FG a little in the worst spot. Damage looks similar to what you had, possibly slightly worse, and a lot longer. Nice to know that other than being a PITA, glassing upside-down is doable for the DIY-guy.

Re: Fibreglass keel repair on trailer

I read that if you have a trailer that has rollers where the keelgard would be it's not recommended to install a keelgard.

I was hoping to fix my keel and put on a keelgard, but I guess I can't unless I get a new trailer.