Capping a thru-hull

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Jim Lucas

I've been stuck coming up with the best solution for capping off an old (Espar heater, I think..) exhaust thru-hull. It's about 2.5" and well above the water line. It looks like it was just cut off near the hull and stuffed with a cork bung. It's one of the last items that the surveyor pointed out that needs to be "properly capped".
Any suggestions on best method of capping this?
Jim Lucas
1999 MKII #1431, M35B, TR/FK 
"Calypso"
Sailing the PNW
Royal Victoria Yacht Club
Victoria, BC Canada

KWKloeber

Jim

I'm not at all familiar with that particular thru hull and the pic doesn't reveal a lot.
Is the outside body smooth/flush/round- I'm thinking a Fernco rubber cap over the top?  Replacing the usual s/s slotted band clamp with an embossed clamp (ABA or WAWB brand).

What is the material?  Would epoxy bond to it - I'm thinking fill it?

Ken
Twenty years from now you'll be more disappointed by the things you didn't do, than by the ones you did.
So throw off the bowlines.  Sail away from the safe harbor.  Catch the tradewinds in your sails.
Explore.  Dream.  Discover.   -Mark Twain

Noah

I am sure there are some creative ways to jerry rig it, but in IMO if you can't find a matching screw-on cap, or no threads remain on thru-hull to affix a cap to, then;
1.  replace thru-hull with a new similar size thru-hull and seacock with valve/capped-off
Or
2. Remove old thru-hull and fiberglass the hole "properly" after grinding a 12:1 bevel inside and out.
1990 hull #1014, San Diego, CA,  Fin Keel,
Standard Rig

Jon W

Where on the boat is it located? Do you have a picture you can attach?
Jon W.
s/v Della Jean
Hull #493, 1987 MK 1, M25XP, 35# Mantus, Std Rig
San Diego, Ca

Jim Lucas

I'll have to get more photos when I get back down to the boat but this is located reasonably high up on the Port quarter. It appears there's no threads left that could be used for screwing a cap onto and a proper fiberglass repair would be ideal. Perhaps a replacement thru-hull that can be properly capped off would be the most cost effective and better than some additional jury-rigged material and hose clamp. 
Jim Lucas
1999 MKII #1431, M35B, TR/FK 
"Calypso"
Sailing the PNW
Royal Victoria Yacht Club
Victoria, BC Canada

scgunner

Jim,

If it's a through hull that's not going to be used and it's above the water line then basically you've just got a hole in the hull that needs to be patched, it's just a fiberglass repair job followed with some painting and blending.
Kevin Quistberg                                                 Top Gun 1987 Mk 1 Hull #273

Roc

Well, the best thing to do with your holding tank vent is to provide two vents for cross ventilation.  This provides oxygen in the tank to promote aerobic bacteria (as opposed to anaerobic, which is what causes the smell).  A high thru hull for the second vent is what is advised.  I did that on my tank.  If your tank is on the same side of this thru hull, you might want to re-purpose the hole.
Roc - "Sea Life" 2000 MKII #1477.  Annapolis, MD

Jim Lucas

I was just about to respond; scgunner, I think you're quite correct and glassing this over is truly the right way to do it.

But, Roc, cross venting the holding tank is a great idea! This is on the same side of the boat and should be able to run a second vent hose. A cheap fix and re-purposing a problem into a solution.
I work hard on keeping the holding tank well maintained and the added vent would be ideal!

Thanks guys!


 
Jim Lucas
1999 MKII #1431, M35B, TR/FK 
"Calypso"
Sailing the PNW
Royal Victoria Yacht Club
Victoria, BC Canada

Jon W

If you use it as a holding tank vent, will it get submerged when heeling underway?
Jon W.
s/v Della Jean
Hull #493, 1987 MK 1, M25XP, 35# Mantus, Std Rig
San Diego, Ca

Jim Lucas

I don't think so. It's located a few inches below the rub rail and far enough astern so that shouldn't be a concern.
Jim Lucas
1999 MKII #1431, M35B, TR/FK 
"Calypso"
Sailing the PNW
Royal Victoria Yacht Club
Victoria, BC Canada

Jon W

I'd make sure. You don't want to fill your holding tank from water ingress.
Jon W.
s/v Della Jean
Hull #493, 1987 MK 1, M25XP, 35# Mantus, Std Rig
San Diego, Ca

Dave Spencer

#11
Jim,
If you do a holding tank cross flow, there's lots of discussion about that here. I did it several years ago and documented it in this post - Reply 17.

https://c34.org/bbs/index.php/topic,6861.msg45889.html#msg45889

Another option would be to relocate the bilge pump discharge to higher up on the hull. I'm not too happy about my discharge just inches above the waterline (and usually submerged under power) under the swim platform on my Mk 1.5.   The flimsy bilge hose is fine for bilge discharge but I get nervous when I see it underwater. A "to do" project is to replace the bilge discharge flange with bronze or stainless and replace the hose with something a bit more robust.

Dave Spencer
C34 #1279  "Good Idea"
Mk 1.5, Std Rig, Wing Keel, M35A Engine
Boat - Midland, Ontario (formerly Lion's Head)
People - London, Ontario

Roc

#12
I have a second holding tank vent placed right below the rub rail, port side.  Exits the hull about were the closet is in the v-berth.  It's well above any heeling angle.  It's placed forward so as the boat moves, it will push any air going in into the tank.  This was advised by Peggie Hall, expert in waste management. 
Roc - "Sea Life" 2000 MKII #1477.  Annapolis, MD

mdidomenico

i think i may have drilled my hole to far aft based on what you all are saying.  i drilled my new tank vent hole just below the rub rail, but basically where the old stanchion vent was.  i may have to have the fiberglass guy fill it when he fixes my bow roller area.  i figured there'd by some spray or the occasionally wash along the rub rail when heeled over, but i didn't think i'd be heeled over that far for that long that i'd siphon the sea into the tank.  mistake number 10k, argh
1989 Cat34 #856, original m-25xp

Jim Lucas

I like the idea of having the vent forward for air flow but wonder just how much air would be moving through verses the possibility of forced water.
The existing exhaust vent at the rear port quarter and high up near the rub rail seems to be a safer bet as it would be even harder to create conditions of burying that area. I'm thinking if I leave the existing station vent and add the rear vent, I may get some flow through venting.
Jim Lucas
1999 MKII #1431, M35B, TR/FK 
"Calypso"
Sailing the PNW
Royal Victoria Yacht Club
Victoria, BC Canada