How to fill 4mm drill hole below water line!!!

[sailingjupiter]

Yes, I win a Darwin award for drilling too far when fitting a new toilet. Before I knew it I had gone too far and drilled through the base and right through the hull. I knew it was too far when a stream of water came shooting out! Never would have thought the distance between the heads base and the hull itself would have been so small.

Yes boat was on the water. Luckily there was a suitable trailer available at short notice to pull it out. Our trailer is in bits at home so that wasn't an option. So thank you to Slinky Spring for the loan.

So how do I repair this very small trouplesome hole? Had lots of advice but all is different. I bought one of those emergency epoxy sticks that cures underwater. But as I say took the boat out anyway to give other options. How about Araldite or the 2 part Plastic Padding epoxy or Plastic Padding gelcoat? I mention these as I have them in stock already. But any recommendations for other stuff.

What about the method. Have been told to just fill the hole as is. Others have said to flare the hole from the outside to give a cone shape and ensure the repair is always pushing against the hull when in water. Should mention I can't really do anything with the inside of the boat as the heads base is an aluminium plate and so a voild of 10-15mm. If I can help it don't want to have to open up this hole.

Any wise words out there that can help this very embarrassed boater! Will I have to worry about any repair for ever? As you can't view the hole really from above I can't tell if it is leaking. Also there will be a toilet above it!

 

[Deleted member 36384]

Download this manual "002-550 Fiberglass Boat Repair & Maintenance" from the West Web Site http://www.westsystem.com/ss/use-guides/

To repair the hull correctly you need to taper the hole when preparing it for filling; its all in the manual above.

 

[Jcorstorphine]

Needs to be well bonded.

I have filled in a number of unwanted holes in my cabin top with one of the premixed fillers and have noticed that even though I had flared out the hole, there is now obvious circles appearing which would suggest that the filler had not bonded very well.

If I were doing it again, I would flare out the hole as mentioned in your posting and first give it a thin coat of resin. As this is getting tacky, use a marine grade filler or one with some fine glass fibre. When dry, sand it back and then give a coating of gel coat which you will need to cover with polythene to get it to dry.

 

[fishermantwo]

The emergency epoxy stick will probably only last 20 years or so even if applied under water. Araldite is ideal as a glue and the two part plastic padding I presume is car bog. this will shrink and leave circles before it falls out.
The hole is only a 4 mm drill hole. I would partly drill through with a 4mm bit then slightly flare the outside with a larger drill or dremel bit. Fill with epoxy filler. Steer clear of polyester fillers. Smear it in the hole and cover with sandwich wrap and smooth it over.

On the inside if you have access you can smear some more epoxy filler over the temporary repair, it probably mushroomed as you pushed it in.

 

[oldsaltoz]

Countersink the holes on the outside and sand the area clean around the hole for about and inch.

Mix a small batch of epoxy resin and add some Micro-fibres or a mix of finely chopped fibreglass to the mix.

Apply to the surface and poke it well in with a tooth pick that flat finish on the outside and wet the sanded area.

Now run some plastic tape over the hole to stop any sagging. Let this cure for 24 hours and sand smooth, re coat the sanded area wet on tacky with 3 or 4 applications of epoxy resin and let it cure.

You can now apply some primer and paint some antifoul on.

I have used this method for many years and have never had any problems at all.

Good luck and fair winds.

 

[simonfraser]

or for a quick bodge, which will raise plenty of eye brows when you've sold the boat, why not find a suitable SS bolt, washer and a bit of sealant & fix your basin properly to the hull ?

 

[grumpy_o_g]

Countersink the holes on the outside and sand the area clean around the hole for about and inch.

Mix a small batch of epoxy resin and add some Micro-fibres or a mix of finely chopped fibreglass to the mix.

Apply to the surface and poke it well in with a tooth pick that flat finish on the outside and wet the sanded area.

Now run some plastic tape over the hole to stop any sagging. Let this cure for 24 hours and sand smooth, re coat the sanded area wet on tacky with 3 or 4 applications of epoxy resin and let it cure.

You can now apply some primer and paint some antifoul on.

I have used this method for many years and have never had any problems at all.

Good luck and fair winds.

Given that water has got to the matting does the OP need to let it dry out at all? I know that, in theory, the mat should be saturated in resin and there's no chance of wicking, but I wondered what your real world experience was?

 

[mitiempo]

I would repair it properly, grinding a taper on both the inside and outside. Use epoxy resin and cut some circles from fiberglass cloth and apply as shown below.

If (when) you have to fill a larger hole from a through hull or transducer you will know exactly how to do it.

From the West epoxy manual:

 

[oldsaltoz]

Given that water has got to the matting does the OP need to let it dry out at all? I know that, in theory, the mat should be saturated in resin and there's no chance of wicking, but I wondered what your real world experience was?

In this case I use a heat gun to dry the area completely and apply a first coat of resin only when the surface was still warm.

As with any epoxy sealing it is very important that any moisture is removed as sealing it will come back to bite you.

Good luck and fair winds.

 

[BAtoo]

You are not alone in this - I cut through the hull on my Squib whilst cutting a hole in the floor for a bilge pump pie to go through - fortunately afloat !!! Simply roughed it up a bit, chamfered the edges (inside and out) and filled it with a chopped mix of fiberglass, beads & resin and a patch of mat on the inside. Sanded down etc and its held for 3 yrs now.....

Also opened a hole on my Drascombe center plate case (by letting the plate drop and hit the case too often ) - this was afloat on Windemere!!.. Hauled her out, rolled her over a bit and bodged some ISOPON car repair into the area, dried overnight and it was fine for as long as we had her.....

 

[Spyro]

As you say you can't get access inside I would tend to fill the hole with epoxy mixed with some filler I would then also grind off the gelcoat on the outside about an inch either side of the hole then build up with layers of cloth and epoxy until level with the gel coat then fair , prime then antifoul.