Plug unused through-hull?

[Lewis]

Hi all,
The previous owner of my Alumacraft added one through-hull to the two already there. I don't plan on a permanently installed livewell, so the holes are unnecessary. What is the best way (short of welding) to seal them off?
Thanks!
Lewis

 

[Bondo]

Re: Plug unused through-hull?

Ayuh,... Put the fitting back in, 'n plug It...

 

[Lewis]

Re: Plug unused through-hull?

Thanks. but "'n plug It" with what ....? sealant? an expanding rubber drain plug? something made for this purpose? something else?

 

[Cadwelder]

Re: Plug unused through-hull?

an expanding rubber drain plug? something made for this purpose? something else?

Yep that's exactly what Bond-o meant, if it's a lined drain plug hole, just put a rubber expanding drag plug in it and you're good to go.

 

[barbosam]

Re: Plug unused through-hull?

I'm assuming this is below the water line if it was intended for a livewell (unless its for the drain side)? It should have a ball valve (or seacock) on it if it is, just close the valve and be done with it, if its below the water line and doesnt have a ball valve than put one on, that is a must.

 

[Lewis]

Re: Plug unused through-hull?

The two that I'm most concerned about are the two below the waterline for intakes (the third one is for the drain; it's a 1.5" fitting that the PO filled with silicone). There are no valves, just cracked plastic through-hull fittings and cracked rubber hoses.

 

[Cadwelder]

Re: Plug unused through-hull?

Ahh okay then:

Option #1 Remove the cracked fittings and replace them with thru hull transom sleeves (they make them in plastic) and then plug them.

Option #2 Remove the cracked fitting and replace with the same thing (if you ever plan to use them for the orginal purpose) and add a short piece of hose with a plug in it.

Option #3 Remove the crakced fittings and get a couple of stainless steel bolts and fender washers and cap off the holes (This is the lease favorable to me).

Seal all the above with 3M 4200 or 5200 is you want it more permanent. Silcone is no good for below the waterline.

 

[barbosam]

Re: Plug unused through-hull?

eek! regular plastic is not approved for the below the water line only Marelon (a fiber reinforced plastic). Below water line thruhulls are nothing to mess around with. I think your best bet would be to replace them with one of these marelon thruhulls and a marelon seacock.

http://www.forespar.com/products/boat-marine-plumbing-mushroom-head-threaded-thru-hull.shtml

Might be a little costly, but I would never trust a below waterline thruhull stuffed with silicone. I suppose the expanding plugs like the ones used on a garboard drain would work too if you can get a matching size, kind of a band-aid but would work. If they are cracked though your first step needs to be to replace them, marelon thruhulls are relatively inexpensive and are great stuff, just dont over tighten anything on them or you could end up with a nother cracked thruhull.

 

[fishrdan]

Re: Plug unused through-hull?

Option #3 Remove the crakced fittings and get a couple of stainless steel bolts and fender washers and cap off the holes (This is the lease favorable to me).

Seal all the above with 3M 4200 or 5200 is you want it more permanent. Silcone is no good for below the waterline.

If you are never going to use the thru-hull fittings (which is sounds like) I would do Cad's option #3 and seal them up permanant.

You can make large washers out of aluminum with a hole saw, then clean up the rough edges with a sander. I've done this a bunch of times, punch out 4-6 holes, bolt them together, chuck them on a drill and sand them smooth on the verticle belt sander. Just make sure the aluminum is thick enough so it does not distort when the SS nut/bolt is tightened.

 

[barbosam]

Re: Plug unused through-hull?

those are some good ideas too; inexpensive solutions.

 

[Yacht Dr.]

Re: Plug unused through-hull?

Just wondering...

Couldnt you just pop-rivet 2 pieces of round alum pieces. One inside..and one outside together with some 5200.. ? ..

Im just a glass guy so just a wondering suggestion/question/comment .. ..

YD.

 

[fishrdan]

Re: Plug unused through-hull?

Couldnt you just pop-rivet 2 pieces of round alum pieces.

Pretty much what Cad had in mind, but using a pop river. Only thing with a pop rivet, you'd have to knock the center out and 5200 the pin so it wouldn't leak. Or use closed-end pop rivets, but those are hard to find unless you order them online.

 

[Lewis]

Re: Plug unused through-hull?

Thanks for all the good ideas! But I was really hoping that some manufacturer made a closed-end through hull fitting. Has anybody ever seen such a thing? Surely I'm not the only one to ever want to semi-permanently seal up a a hole below the waterline and not have to worry about it...
Lewis

 

[Huron Angler]

Re: Plug unused through-hull?

I like bond-o's idea because it's the simplest. But seeing as how the sleeve is already cracked, and you say you don't want to worry about it...this is a more permanent solution.

This method will work as long as you can access the interior of the hull and you use gluvit to keep it watertight.

I know cadwelder's ideas will work too, so it's really a matter of what you prefer.

 

[Lewis]

Re: Plug unused through-hull?

HA,
That is so cool! If I didn't already have more holes than I want, I think I'd cut a hole just so I could make a patch like that! Seriously, I think I might do that for the big drain hole that's above the waterline, but the ones below the waterline are too close to the, the, uh, uh, what's the word for the line where the transom meets the bottom? So I couldn't get rivets all the way around.
Lewis
P.S I might have to get a rivet gun now. That's really cool, too.

 

[Yacht Dr.]

Re: Plug unused through-hull?

Thanks for all the good ideas! But I was really hoping that some manufacturer made a closed-end through hull fitting. Has anybody ever seen such a thing? Surely I'm not the only one to ever want to semi-permanently seal up a a hole below the waterline and not have to worry about it...
Lewis

I have about an hour of research and looking on the web/forums and have found no "Blank through hull fittings" ..

You might want to dig deeper though..

Im thinking of something that can be modded at the moment ..

YD.

 

[Woodonglass]

Re: Plug unused through-hull?

I'll give it a try.
When I was in the Pool business we used these plugs to winterized our pools. 1 1/2 " standard threaded PVC plugs with flat rubber washers.

http://www.americasbestpoolsupply.com/p-5408-threaded-winter-plug-1-12-inch.aspx

Used with one of These...

http://plumbing.hardwarestore.com/5...rs-nuts/1-1-2-pvc-slip-joint-nut--664199.aspx

You might make it work.

But Hey, I'm just an Old Okie that'll try anything!!!!!

 

[Bob_VT]

Re: Plug unused through-hull?

Just a dumb cheap suggestion......... whittle (remember boy scouts ) a round hardwood dowel to oversize ...... coat with 5200 and hammer in The 5200 will keep it sealed up.

I do like the pool plug too......... but I was thinking cheap

 

[fishrdan]

Re: Plug unused through-hull?

the ones below the waterline are too close to the, the, uh, uh, what's the word for the line where the transom meets the bottom? So I couldn't get rivets all the way around.

You don't have to rivet into the boat's skin. Use a washer (aluminum disc) on the inside and outside, slather them with 5200 and bolt it through the center. If it's a 1" hole, use a 1.5 washer (or bigger) so there's 1/4" contacting the boat's skin.

 

[Lewis]

Replying to my own 10 year old thread with what I think is a pretty good solution. 8AN 6061 aluminum pipe plugs and matching nuts: https://www.amazon.com/gp/product/B0989Z329Z

https://www.amazon.com/gp/product/B076CGBB4L

I've gone 10 years with just a PVC pipe plug and PVC nut. No leaks, but there's no UV protection in the PVC and it's got to be aging some. I feel better with solid aluminum!