dime-sized hole repair

Something has placed a hole in the bottom of my boat. Hole is about dime sized in diameter and is below the waterline. Surrounding fiberglass is in good condition, with the glass that was damaged still attached on the inside of the hole. I cannot access the backside/inside of the hole. Can I just patch with marinetex? I haven't ever used the product before but wanted to know the limitations of the product before I try it. I plan on using a wire brush to completely remove any loose glass, sand about 3/4" around the perimeter and push the marinetex well into the hole, and smooth out to overlap the hole. let it dry and the sand. Will this work?

I do not think that marine tex would be strong enough unless it has a 5hp motor on it !! Bottom of the boat takes a real beating. You really need to repair from the inside first. If not, you could taper the hole out to about 3" & use a gel polyester resin & fiberglass cloth. You could get mat & pull it apart, mix with activated resin & make a ball & press in into the hole, smooth out onto the tapered area. Then get a piece of cardboard & press up against hull so it will be close to the shape of hull & stay in until it hardens. You will then probably have to put another layer of mat over it again. <U>BUT I do not know if this would be sufficient, espically if you have a fast boat.</U>

There are some options out there, but if it were my boat, I wouldn't trust an outside only repair. I would find a way to get at the inside of the hull and lay down some new cloth, extending out from the edge of the hole by 3-4" each way. Then, final repair it from the outside.

Anything short of this or a professional repair and you will always be wondering if it broke loose on that last wave you hit.

Ok, thanks guys. Guess I will have to cut out the plastic compartment tubliner and have a pro access the inside as well. I really appreciate y'all sharing your thoughts with me and I will take your advice

Update: we tried to access the inside by cutting a large hole in the inner compartment storage tub, only to be blocked by a thick stringer. But we did find that just inside the hole in the hull the same stringer sits just 1/2" inch away. So my repair guy wants to stuff and layer fiberglass & resin cloth building out the stringer to where it would directly support and fill the hole, then lay some cloth on the outside to cover the hole, and the sand & finish. Also we agreed that he should probably lay an equal amout of cloth on the boats opposite side to prevent the repair from acting like an unopposed trim tab. Am I making sense? The damage is right on the far starboard end of the pad.

As I read where this hole was, I wondered if it was a gel coat blister? Was the hole leaking water into the boat? When we used to build boats, all too often one of the guys would miss rolling out the air bubbles during the layup process. These air bubbles, usually in the strakes or pad edges, would eventually lead to the gel coat blistering. We'd fix with more gel coat--after we prepped and dried the area.

If it was a blister the glass inside the boat should not have been affected at all. Generally, the boat doesn't even leak.
Rick the Carpetman carpetman61@bassboatcarpets.com

This was a complete through hull hole. Shows signs of being hit. Still unsure of how I did it