The Boating Forum - thru-hull installation help
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04-06-2005, 05:40 PM
I am getting ready to install two bronze thru hulls below the water line to rig two separate live wells on a 23 foot center console. The thruhulls will be valved for shut off in case of emergency.
Besides carefully measuring and selecting the correct spot to place these, how does one go about installing them? I assume I need to strip any bottom paint in the area. Once the hole is drilled, should I use 5200/4200 smeared on the inside of the cored hole and to seal the thru hull in place? Is it that simple?
I already have one livewell/washdown pump thru hull in the boat. It doesn't have a strainer on it, and it tends to clog. I'd like to swap that one out. Once I get the nut off on the inside of the hull, can I just persuade it out with a hammer, or do I risk damaging the hull if its bonded in there? Can they be removed?
Thanks for your help.
People want to use way to much sealer in way to many places when installing one of the things. Look it takes very little to make sure they don't leak - any more than that is not only wasted but it makes it just that much more of a mess to clean up if you ever have to or want to remove it.
So, find the stem size of your fitting and buy a hole saw of the appropriate size. That is to say get it the same size as the stem or 1/8" larger, but no bigger than that. For whatever its worth those throw-away hole saws (bi-metal) tend to last longer in Glass than good ones and of course they only cost about a third as much).
So drill your hole. Then take the thru hull and put a bead of 5200 right where the stem hits the inside of the mushroom head. Make that bead no larger than what you'd put on a toothbrush. Do not smear it around the hole, do not put it up on the stem, do not put it anywhere other than right at the 90 degree junction where the pipe hits the flat. That little bead is all you need or want.
Stick the thru hull in while someone else goes inside the boat and tightens down the nut. You stay on the outside holding the thru hull (look inside of it to see the little protrusions you'll use to hold it with whatever is handy). Tell the person on the inside to screw it all the way down and to get it as tight as they can by hand, but no tighter. Then leave it alone for a day or two. Come back with the Channel locks and snug the nut down real well, but do not go absolutly nuts on it.
That is all there is to it. The thru hull will not leak, not a drop. When the time comes to remove it just take the nut off. Then make sure you leave the hammer at home. Just put your foot on it and step down. Even ones that have 5200 smeared all over hell and gone will usually break loose if an adult steps on it and maybe hops up and down a little bit.
04-06-2005, 07:45 PM
I would use seacocks
04-06-2005, 08:06 PM
I like Thom's advice but after cutting the hole I would wet the walls of the hole completely with your favorite marine epoxy. That way water in the bilge will not get into the core material around your hole and rot it out.
04-06-2005, 09:03 PM
Is you hull cored? "inside of the cored hole and to seal the" If so you need to remove core and fill with glass to keep the hull from flexing a soaking the core.
04-06-2005, 09:19 PM
my 2 cents on drilling the hole: start from the inside of the bilge, once the centering drill bit comes thru the outer hull, finish drilling from the outside of the hull (same way you cut a hole for a lockset in a door) then follow the above instructions.
Codydog has the correct idea. You will need to remove some core material from about 3/4' around the drilled out hole. I bought a small tile grout removal tool from a tile store and filed the end to a sharp blade to scrape out the core material. You can jury-rig any type tool with a 90 degree bend with a sharp end to do the job.
Fill in removed core area with mixture of epoxy and fiber filler material. This will keep the hole from flexing and compressing when you tighten down the fitting. If the hole flexes or compresses you will have soaking of the core over time.
I have a 6 year old cored hull and all my fitting are done this way...no leaks
04-08-2005, 04:18 AM
To remove the core, chuck an allen wrench into an electric drill and go to town, once about an inch has been removed, mix up some west with balloons and fill void, let kick-off, redrill hole to clean up, lots of 5200 on the thru-hull, done....Mick
Someone please name one one 23' center console boat that has a cored hull.
04-09-2005, 06:25 PM
Carolina Skiffs are cored.....Mick
04-09-2005, 07:43 PM
IMO, all thru-hulls should be installed with backing plates to distribute the stress. I use a piece of 3/4" plywood, drilled out and thoroughly epoxied.
04-09-2005, 07:48 PM
Today I was under my boat, which sits on a trailer, to bleed the hydraulic brakes. While under the boat I got a great look at the bronze thru-hull for my live well/wash down. What I saw gave me pause to consider that the thru-hull was only 2"-3" from one of the trailer rollers. If it weren't for the load-guides I use to center the boat, it would be easy for the thru-hull to ride up on the roller when retrieving, and who knows what that could do; probably break it.So, my message is: when you locate the thru-hull, keep the position of the thru-hull relative to the trailer rollers, or bunkers, in mind to avoid future problems.Good luck,Al
04-11-2005, 07:05 AM
Thanks for the help. I hope to get to work later this week! Spring is here