Forward fish box drain (Update)
 

1972 20 SF.

The previous owner glassed over both the inside and outside holes of my forward fish box. I can't even tell where the original hole was on the outside of the hull. What is the easiest way to drill the hole in the original location. I would think the angle needs to be perfect so the flange of the tube lines up correctly both inside and out. The preferred method to drill this would be from the outside I think but I don't know the exact location to get the hole to come out where it should on the inside. Anyone ever done this or have any ideas? Thanks.

Others will likely have a better idea but my thoughts go to going from the center of the drain well assuming it's still there and doing a very small pilot drill bit out ward . You can the take a PC of coat hanger wire and run it thru to check your alignment. The inside box and the outside should be very close in there alignment already but you could check you hole and adjust it from the outside within reason

That was what I was thinking too. Any idea how thick that area is? Is it right against the hull or will it be inner liner followed by a void than the hull? Thanks

So I drilled a small hole from the inside after removing the hack job patch that covered it. The old hole looks to be filled with just resin. Does anyone know if there was a wood block under there like the original thru deck scuppers? Also can someone measure the inside diameter of this drain for me so I can drill the right size hole? Thank you.

When I removed that drain there was a big glop of "potter putty" between the liner and hull and there is definitely a void in there. I think it's a pretty notorious leaking spot. I replaced it with a more substantial thru-hull.

I was thinking of drilling it out a little bigger than a fiberglass tube from McMaster Carr. Then insert the fiberglass tube and ensure it is flush with the bottom of the hull by placing a board and support under it to hold it in place then inject west system with a syringe around the entire tube from the inside to bond it in place. Remove bottom support, insert plug and go. Any issues with this plan

I wanted a mechanical bond in addition to sealant/adhesive so I used a low profile threaded thru-hull cut down to size. It protruded a bit but it's not really running surface right there anyway.
The only worry I would have with what you want to do is not having the epoxy just run away when you inject it. Also, you have to figure you get a lot of vibrational forces right there when blasting through chop so you want a substantial bond.

Chance, I had a similar problem with the OEM scupper tubes, where the wood block surrounding one of them was rotted pretty good. I carved out the rotted wood as best I could and then basically filled the entire hole with epoxy and redrilled it like you're planning. Instead of using straight epoxy which will just run all over the place, I'd thicken it to about the consistency of peanut butter to keep it from running and then use an empty caulk tube (many FG suppliers carry them) to force thick epoxy into the gap.

Here's the text of a post I made on the subject that might give you some more ideas: 06-04-2007, 12:13 AM
Epoxy fill of scupper holes using PVC core/pilot hole worked out well - mismatch between original hole & drilled hole at bottom was about 1/32", easily filled with 5200. Would have probably been better if I had used a flat wood drill bit with pilot feature instead of conventional bit which tended to walk.

Epoxy Fill: You will probably discover that the wood block is no longer sealed to the hull, so if you try filling it with plain epoxy as I did, it just runs out at the bottom. Next try with epoxy thickened to about apple sauce consistency worked well. I used MAS slow cure hardener & chilled it & resin in fridge first; otherwise it wants to kick off pretty fast once you pour it in caulk tube! Ended up using 3 caulk tubes, but wasted one due to sealing problem mentioned above.

Brass Tube Installation: (Ordered 1" ID x 6" long brass tubes from Boat Owners Warehouse, about $6 ea., got them overnight) The hole came out about 1/16" oversize due to drill walk, so filled it with 5200 as I slid tube in from top. Installed drain plug in top of tube first for leverage. Need to flare bottom of tube right away to keep 5200 from running out bottom because it's pretty slow to cure. Used a threaded rod, with nuts, washers and a 1/2" drive socket to get the flare started.

Results: After letting the 5200 cure for about 5 days, took the boat out for about 6 hrs, 4 of which was at anchor, bilge pump OFF for entire time. Pulled boat out, pulled bilge plug - it was dry, didn't leak a drop! :)

Here's a slideshow with some pics I took of process. I like the idea of using a threaded thru hull for your application, so you'll have some mechanical compression keeping it together to fight vibration and relative motion between hull and inner liner/box that might loosen or crack the bond with a tube just stuck in with epoxy. In your case the trick will be to get a complete ring of thickened epoxy around the hole in the gap between box and hull. You don't have a 4-5" long hole to fill like I did, so maybe you could just use a putty knife or chisel blade in an exacto knife to fill the gap, or put some tape on inside of hole and drill some small holes around circumference of big hole and use caulk gun to inject thick epoxy thru them.

Oldfielder what did you use for a low profile threaded thru hull? Thank you

Pretty sure it was a 3/4 bronze mushroom. I dry fit it, measured and marked the threads and then cut it down with a hacksaw. Two man job to install. One guy holding the nut on the inside and one guy turning it with a step wrench on the outside. Pretty sure I sealed it with 5200. If I were you I would drill the hole and then fill the void around the hole with peanut butter. Let that set up and then use above method. This way when you go to install thru hull you won't compress the space.
http://www.perko.com/catalog/underwa...use_with_pipe/

That's pretty close to how I did the fwd drain on my 18SF.
Only difference is I slid it in flush(ish) with the inside of the fish box and let it hang long on the outside.
When it was all kicked off I just sanded it flat, primed and painted.

Also I drilled my hole pretty close to the size of the fiberglass tube, and sanded a small chamfer on the hull side of the hole.
I filled the void between hull and fishbox with thickened resin, sanded and resined up the tube and slid it home.
Troweled a little epoxy into the chamfer and then like I said earlier, sanded it all flat.
Two seasons, no leaks or cracks.

Zac, explain to me what a chamfer is/does. Thanks

Just kind of sanded the outside of the hole (hull side) with a slight angle all the way around, instead of a squared off hole. Just a way to get more epoxy around the frp tube and bond it to more of the hull.
Same way you'd grind back a hull repair, but not so extreme.

I replaced the forward fish box drain on my buddies 23 seacraft with an FRP tube as well, but in his instance I did grind back the hull just as if I was doing a hull repair, and laid glass over the opening after I epoxied in the FRP tube. Then re-drilled it from the inside.
He likes to pound the crap out of the boat, so I thought a little more hull integrity couldnt hurt. :o

You just painted your hull didn't you? Might have to take the simpler approach to avoid having to repaint a section.

Ok, so I went with the simplest attack and decided to just put a new brass drain tube back in. I drilled the hole with a one inch hole saw and this is what I find...

http://i1326.photobucket.com/albums/...psebb88ca0.jpg

http://i1326.photobucket.com/albums/...ps54ce8594.jpg

If you can't tell from the pictures there is a large void on the aft side of the hole between the hull and liner, I can stick my finger as far back as I can reach.

What the hell do I do now?

Get some 1" dowel rod. You will need a couple of pieces about 6" long and one just the thickness of your hull - attach that piece to the center of a small piece of plywood. Cover it in saran wrap and plug the hole from the outside - brace it in place. Mix up some cabosil with some glass fiber in it - you will need a couple of batches big enough to fill the void. Cover the other dowel pieces with saran wrap - you will use these as 'plungers' like in a syringe. Fill the hole with cabosil and work as much as possible into the void. Refill the hole with cabosil then push the plunger in to force the cabosil into the void. Leave it in to set then the resin will release from the saran to let you pull it out. You may have to bore it out and repeat it to get a good fill.

Forgot to say to smooth up the edges of the hole first - you don't want to tear or cut the saran wrap. A 1" polyethylene rod is better but not in most folks shop.

Before I do that, do you think it would be a good idea to put some cabosil in the void by using my finger so it has something to stick too and so I don't just keep pushing all that stuff aft when it gets into that void via the plungers?

I heavy some west system thickened epoxy already in the tubes that says to just mix 1:1. I forget the number of the system but do you think that would work. It's sags very little if at all

probably fine - if you have milled glass fiber it would be a bit stronger.

Probably a good idea but you want to get it back in a good bit in all directions

The hole only goes aft, the rest of the drilled hole is solid

Anyone ever has this issue?????

Mine had a void too, just mixed up some thickened epoxy/cabosil, and pastry bagged it in there.
Glassed my new tube in while it was still green.

Thanks Zac, that is what I did too followed by filling the entire new hole I driiled with the same. I'll re drill the 1" hole today and see if I succesfully got it all filled in. If so I'm just going to replace with the brass tube method.

Got the hole filled and re drilled and it looks great. One last question, in the picture below, can I flange that as is or should I cut it down? The black line is the bottom of the hull. Itis a standard three inch brass tube. Thanks

http://i1326.photobucket.com/albums/...psb8811d4d.jpg

Chance

I would consider something with more strength and wider flange like (Gemlux S/S).
Measure first with locking nut tight in place and flush against your inner liner. Cut the threads down then reinstall, seal it with 4200 and keep an eye on it. Flexing could slip between hulls & crack weaker type tubing.

http://www.foreandaftmarine.com/VT-hull_fittings.jpg

Thanks chuck, that's probably gonna be what I go with.