Check your sink drain hoses...

Jun 25, 2004
475
Hunter 306 Pasadena MD
I close all my thru hulls every time I leave the boat. So doing some work today, I opened the thru hull under the sink in the head and wondered why my hand was wet... Check out the OEM hose Hunter used for the drain:
sink_drain.jpeg
No wonder I was seeing water stains next to the head. Anyway, all the advice I've read says you should only used heavy duty reinforced marine hose below the waterline, so I replaced this cr@#$p with the heavy black wire-reinforced hose you'd use for engine raw-water pickup, or other "serious" applications. Having just replaced 3 thru hulls this spring, I've already upgraded the raw-water pickup, macerator, and head pickup, but hadn't yet gotten to the galley and head sink drains.

It seems that those corrugated drain lines would be just as glad to sink the boat as any other below water line hose.
 
Jan 4, 2006
6,444
Hunter 310 West Vancouver, B.C.
How very true.

Saw someone else mention this problem years ago here and decided to take a look at my galley sink hose. YIPES :yikes: ! Exactly what you are showing. Ripped it out and used heavy vinyl hose without the fancy ribs.

I've got to wonder how many years they used this cheap hose and have they stopped yet. Every other hose on the boat was top quality but here ? .................. not so much.
 
Feb 10, 2004
3,918
Hunter 40.5 Warwick, RI
Been there, done that. See my post from 2016. Sorry you didn't see it sooner......

 
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May 24, 2004
7,129
CC 30 South Florida
The discharge to the head sink drain is above the waterline where those hoses and plastic through hull ports are OK to use. Your fresh water tank does not hold enough water to sink the boat. The Galley sink drain is a different animal discharging below the water line and hoses, clamps and thru hulls shoul be periodicall inspected. The only thru hull valve I shutoff when I leave the boat unattended is the head intake valve as inspecting the valves and seals in the head is not practical.
 
Jun 25, 2004
475
Hunter 306 Pasadena MD
Well, I was pretty sure I wasn't the first one to notice this, but it probably can't hurt to mention it again. I actually think I had seen Rich's posting a while back. But there are a thousand things to do, fix, and upgrade on a boat, so you pick and choose and prioritize. After I replaced the 3 thru hulls this spring with flanged 3-bolt sea cocks, I had my eye on the 2 sink drains and thru hulls: just hadn't gotten to them yet. But finding a hose leaking below waterline will get your attention.

BTW: both sinks drain below waterline on the 306, and the fresh water tank isn't involved.

Also BTW: the head pickup hose was originally the thin white vinyl hose used for most other toilet hoses. This stuff isn't as bad as the corrugated hose, but it still tears pretty readily when it's 15 years old: it got replaced by the heavy duty black reinforced hose.

As for closing all thru hull valves when leaving the boat: this is clearly a work-vs-risk decision. I've been doing it for 16 years, and will continue to do so. It's not that big a deal. I'm sure many others will decide otherwise.
 
Aug 12, 2020
53
Lancer 36 Pago Pago
I replaced the sink drain through hull on my boat last week in water, as the plywood pad had deteriorated and allowed significant leakage into the bilge. I made a replacement pad from 3/4 FRP; I installed the valve and hose today after letting the 5200 cure for a week. The wooden plug i made to keep the ocean out did a fine job; I remembered it was there when the water did not drain out when i tested the sink drain......:facepalm: Through hulls are well worth keeping an eye on, and I close mine when leaving the boat.
 
Jun 25, 2004
475
Hunter 306 Pasadena MD
I replaced the sink drain through hull on my boat last week in water, as the plywood pad had deteriorated and allowed significant leakage into the bilge. I made a replacement pad from 3/4 FRP; I installed the valve and hose today after letting the 5200 cure for a week. The wooden plug i made to keep the ocean out did a fine job; I remembered it was there when the water did not drain out when i tested the sink drain......:facepalm: Through hulls are well worth keeping an eye on, and I close mine when leaving the boat.
Man: you did it in the water? How the heck did you do that? Even if you didn't replace the actual thru hull (mushroom) fitting, I'd think the water would be coming in like a geyser while you fiddled around trying to get the old valve unscrewed and the plug in.

The 3 that I replaced were for the same reason, though: the plywood pad was rotted from sitting in a small amount of water.

Ahhh... you must mean you put the plug in from the outside, and presumably didn't replace the mushroom fitting. That's a bit more tame.
 

Bob S

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Sep 27, 2007
1,771
Beneteau 393 New Bedford, MA
My Bene uses the same corrugated hose and I have been suspect of it. I always shut the through hulls when not on the boat. Guess I’ll be changing that hose this off season. Thanks fo the heads up
 
Oct 26, 2010
1,883
Hunter 40.5 Beaufort, SC
Does anybody have a suggestion for a reasonably flexible 1 1/4 ID reinforced hose for the replacement. At least on my boat (a Hunter 40.5) the sink drain tailpiece is 1 1/4 inch. I have not been able to find a flexible 1 1/4 inch reinforced hose suitable for below the water line applications that will make the bends I need to make for the installation. Suggestions are appreciated.
 
Jun 21, 2004
2,532
Beneteau 343 Slidell, LA
Man: you did it in the water? How the heck did you do that?
Ahhh... you must mean you put the plug in from the outside, and presumably didn't replace the mushroom fitting. That's a bit more tame.
Had to do similar exercise on my Hunter, years ago. Was getting ready to lockup for the day and closed the valve on the galley sink thru -hull. The valve stem broke off and needless to say, the ball was still in the open position! Water poured in. I was able to jam the stem back into the valve and used plumbers epoxy to slow the water to a manageable flow. Use a plug to plug thru hull from outside until I could get a new valve. Disassemble old valve and installed the new one on the existing thru hull fitting. Opened the valve and knocked out the plug from inside, using a long screwdriver. Then there was the time that I replaced the stuffing box packing in water......
 
Jun 21, 2004
2,532
Beneteau 343 Slidell, LA
My Bene uses the same corrugated hose and I have been suspect of it. I always shut the through hulls when not on the boat. Guess I’ll be changing that hose this off season. Thanks fo the heads up
Interesting, Beneteau used Trident sanitation hose on mine; same hose that was used in the head plulmbing. I would try to use something similar (Raritan sani flex); may have to get another tailpiece to fit the hose. I believe the sink drain hose is 1 1/2" but not absolutely sure. Its good stuff, definitely tougher than corrugated hose and wouldnt expect any deterioration for years to come.
 
Aug 12, 2020
53
Lancer 36 Pago Pago
Man: you did it in the water? How the heck did you do that? Even if you didn't replace the actual thru hull (mushroom) fitting, I'd think the water would be coming in like a geyser while you fiddled around trying to get the old valve unscrewed and the plug in.

The 3 that I replaced were for the same reason, though: the plywood pad was rotted from sitting in a small amount of water.

Ahhh... you must mean you put the plug in from the outside, and presumably didn't replace the mushroom fitting. That's a bit more tame.
I used a plastic bag and 5200 to cover the outside; cut off the old valve with an angle grinder, prepped the new through hull with 5200; dove down to insert the through hull once the nut had been cut by my inside help...he prepped the inside surface and had the pad coated in 5200....the through hull was already plugged with a custom fit plug, inserted, held while tightened....other than an initial flood during the switch, no leakage....problem solved. Needs a diver and an inside man, and wife manned the pump:)
 
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Jun 25, 2004
475
Hunter 306 Pasadena MD
Had to do similar exercise on my Hunter, years ago. Was getting ready to lockup for the day and closed the valve on the galley sink thru -hull. The valve stem broke off and needless to say, the ball was still in the open position! Water poured in. I was able to jam the stem back into the valve and used plumbers epoxy to slow the water to a manageable flow. Use a plug to plug thru hull from outside until I could get a new valve. Disassemble old valve and installed the new one on the existing thru hull fitting. Opened the valve and knocked out the plug from inside, using a long screwdriver. Then there was the time that I replaced the stuffing box packing in water......
I used a plastic bag and 5200 to cover the outside; cut off the old valve with an angle grinder, prepped the new through hull with 5200; dove down to insert the through hull once the nut had been cut by my inside help...he prepped the inside surface and had the pad coated in 5200....the through hull was already plugged with a custom fit plug, inserted, held while tightened....other than an initial flood during the switch, no leakage....problem solved. Needs a diver and an inside man, and wife manned the pump:)
Y'all must have ice water running in your veins. Well done! :cool: Nevertheless, I think I'll wait until haul out to make more holes in the boat...
 
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Oct 26, 2010
1,883
Hunter 40.5 Beaufort, SC
Can't remember what I used but will check it out and let you know next time I am at the boat
Thanks, I've found plenty of 1 1/2 inch ID hose but can't find really flexible 1 1/4 inch. The problem is the bends I have to make.