To glass or not to glass entire bottom? Want opinions

[mcpapa]

I'm putting my 4" glass tape on my seams of my V12 now. Here in the pacific northwest a lot of our beaches are rocky or gravelly. I was considering putting a layer of 4 oz cloth on the bottom to at least make it a little more abrasion resistant. Anyone else out there do this or have any thoughts on this subject? I'd like to hear opinions.

[Troutlet]

This forum is great for just bouncing ideas off of people isn't it?

If I was going to be running aground often I would put a layer of something extra on the bottom just to keep that one sharp rock in the bunch from making through to the wood.

It will add epoxy of course but if you are planning on keeping the boat for many years then it seems like a good precaution. A lot of builders do that and a lot of the plans specify cloth on the bottom.

[DrBones]

My thoughts to this are that the bottom of any trailered boat will suffer. Without a doubt you will get scratches/dents that will go through the paint and epoxy and if you don't stay on top of this on a regular basis, i.e. sanding and re-coating with epoxy, water will get into the wood.

I would think that something like 9oz fiberglass cloth will protect your boat better than just epoxy and paint. That and an additional two coats of epoxy plus some hard paint should last you a good while and you won't have to worry everytime you hit the gravel.

[jasonmcintosh]

I definitely would. Rocks can go right through paint, and once the wood gets wet, you really should do something to dry it out and seal it up. Especially if you're going to keep it outside. These wood boats take a bit more care than typical metal, glass or plastic boats. The extra glass will add weight and cost, but if you plan on keeping the boat for awhile, I think it'd be a good investment.

Also, 5 months back or so I read a post of a guy who cracked his non-glassed hull when he stepped out of his small boat (D5 maybe?). There were some extenuating circumstances though: he was a rather big fella for the small boat (200+lbs?), the boat was on a hard uneven surface (i.e. not in the water), and he didn't use the high grade marine plywood sold on this site. So I'd be a little concerned about overall strength of a non-glassed hull myself. However, I've never seen any bateau boats other than my GF18, so you've got to take my concerns with a grain of salt.

EDIT: Actually, I've had a bit of change of heart about this. Epoxy saturated plywood, covered with a good paint such as System three's primer and topcoat makes a pretty durable surface. It'd take quite a scratch before you'd reach untreated wood. My S3 paint was weakened a bit by all of the tint I put into it, but I haven't had a scratch go past the primer yet, let alone show any fiberglass.

I think that it comes down to just how rough you want to be with the boat. The smaller boats won't hit the rocks with the same momentum as the bigger ones, so the glass may not be necessary.

So there, you've got two opinions in one reply. I hope I've helped!


jason

[PJPiercey]

From my experience with the V12 I would just add extra glass along the keel line and the skeg. There is enough of a V to the bottom that only the keel line comes in contact. I would also make my skeg wide enough to add a metal strip to the bottom of it. The kids wore the skeg down to the wood in no time by draging it along the bottom.

Paul Piercey

[LarryA]

I don't think I have ever heard someone say "I really regret glassing the entire bottom." The reason is that it adds very little weight and cost and these small boats generally get abused. But you do occassionally hear people so they wish they had glassed it. Just as you said, the beaches often have abrasive material in them that can damage the hull.

[Laszlo]

Go for the glass. 4 oz is plenty for most "encounters", 9 is probably overkill. 6 would be a good compromise. I used 4 on my Cheap Canoe and am putting 6 on my V12.

http://www.lmorocz.com/BoatBuilding/pt01scrapes.htm

Have fun with the boat,

Laszlo

[JerryF]

During the winter months, I was mulling over this same question. I didn't glass the bottom of my GV11+ originally and in one season of use it got several deep scratches from pulling it up on rocky beaches.

All these dings and gouges were right along the keel. The GV11 has a 10 degree deadrise so not much of the bottom was being affected. I decided to glass only a strip about 10 inches wide along each side of the keel. Also to put this strip from just above the turn of the bow back just about 6 feet not clear to the stern. That covers the area where it was getting the impacts.

I used 9 oz FG because that is what I had on hand but I would have used lighter material if I had it. The harder surface of the FG / epoxy should make dings less intrusive into the hull though I will still have to paint over the scratches every year.

You can always go back and cover the bottom later (just sand the paint off). If my experiment isn't good enough that's what I will do.

JerrF
GV11+

[jacquesmm]

We sell 4, 6 and 9 oz. woven fabric for that.
It does not add much weight and is an option on all our boats.
You decide how much protection you need: 4, 6 or 9 oz.?

We are also testing a graphite bottom since a few weeks. I use a Hiawatha canoe almost every day, drag it up and down the ramp, on the beach etc. and the graphite bottom does not show any scratches.
The graphite is not listed at our web site but we have it in stock.
You simply mix it with resin and apply it as a coat of paint.
Beware, once it's on, it's on. It is almost impossible to sand.

[mcpapa]

I've used graphite before a little. So, if it's not sandable, does that mean that you can't get paint or antifouling paint to stick to it? It dosen't do anything for UV protection of epoxy doese it?
As for the fg cloth, what about just doing a strip along the center rather than the whole bottom?