Bilge Pump Thru-Hull Location

JWS

1st Mate
Joined
Jul 25, 2022
Posts
235
Likes
166
I know it isn't ideal but some rv antifreeze dumped in the bilge with the pump running buys you some protection from freeze up... Until it cycles again anyway.
 

Crusty Coastie

Commodore
Joined
Feb 18, 2015
Posts
829
Likes
781
Location
Boston,Mass
First Name
Pete
Boat Make
38 Holland ''Orion''
Like John said , if they are low like that make sure the line loops up high , or has anti siphon etc , I was moving a sailboat and the bilge hose had been shortened many times so on a starboard tack it would back and fill with water , quite exciting at night in a strange boat
God forbid that they spend the $20bucks and twenty minutes to change it instead of adjusting their man bun for an hour.
 

BlakeH

1st Mate
Joined
Feb 14, 2021
Posts
204
Likes
113
Location
Long Island, NY
First Name
Blake
Boat Make
25 T Jason
I like them on the helm side of a lobster boat. That way I can keep an eye out as to when the pump comes on and what’s coming out. There can be Lots of important information coming out of the bilge. I want to see it
This is why I’m moving it in the first place. It was at the transom and I like to be able to see it
 

BSEA

1st Mate
Joined
Aug 29, 2017
Posts
357
Likes
207
Age
60
For what it's worth, I recall some bilge pump install instructions call for a minimum of 12" above waterline for discharge outlet.
 

LadyMaureen

Admiral
Joined
Apr 27, 2012
Posts
1,009
Likes
1,496
Location
South Shore Long Island
Boat Make
Wesmac
I ran my rear lazarette pumps (primary and secondary) to discharge underneath my gunwhale at transom....this way I always know when the pumps are going on. The switches with lights are great but they are 30 ft away at the helm. When I am in the cockpit I see the pumps come on and dump water onto the deck near the scupper. Some may disagree, but I will never not do this, I love the concept. Good luck.
 

Diesel Jerry

Admiral
Lite User
Joined
Oct 25, 2015
Posts
11,241
Likes
10,833
Age
43
Location
South Freeport, ME

Clarke

Deckhand
Joined
Jan 9, 2022
Posts
66
Likes
19
First Name
Clarke
Boat Make
Calvin Beal 30
This is probably a dumb question, but could bilge water be sent out the exhaust along with the cooling water? As long as they don't feed back to each other? Anti-siphon / check valves?
 

Diesel Jerry

Admiral
Lite User
Joined
Oct 25, 2015
Posts
11,241
Likes
10,833
Age
43
Location
South Freeport, ME

Clarke

Deckhand
Joined
Jan 9, 2022
Posts
66
Likes
19
First Name
Clarke
Boat Make
Calvin Beal 30
That makes sense. Yes, probably one of those things not to keep hidden anyway. At least if its up high, the sound of running water hitting the sea surface tells us something is up!
 

Crusty Coastie

Commodore
Joined
Feb 18, 2015
Posts
829
Likes
781
Location
Boston,Mass
First Name
Pete
Boat Make
38 Holland ''Orion''
I ran my rear lazarette pumps (primary and secondary) to discharge underneath my gunwhale at transom....this way I always know when the pumps are going on. The switches with lights are great but they are 30 ft away at the helm. When I am in the cockpit I see the pumps come on and dump water onto the deck near the scupper. Some may disagree, but I will never not do this, I love the concept. Good luck.
My Laz pumps out at the tuna door ramp and is check valved.Good to see its actually going when you've been backing on a fish for a while and theres been a foot or so in the cockpit a few times.
 

Fouraces59

1st Mate
Joined
Jan 7, 2013
Posts
493
Likes
352
Location
Hull, MA
First Name
Jay
Boat Make
26 Seaway CC
I like them on the helm side of a lobster boat. That way I can keep an eye out as to when the pump comes on and what’s coming out. There can be Lots of important information coming out of the bilge. I want to see it
Absolutely, One day the oil pressure sending unit cracked and oil was leaking into bilge. Having the discharge on side with helm where I was hauling gear, let me catch it quickly and shut things down. Quick tow in and fix and were back out hauling gear in the afternoon. Never want bilge discharge where I can't see them easily
 

Kailua Kid

Commodore
Joined
Jan 14, 2019
Posts
810
Likes
685
Location
Bainbridge Island
Website
www.gibbonslawgroup.com
Boat Make
General Marine 26; Klamath 19; Sparkman & Stephens Yankee 38 sloop
Absolutely, One day the oil pressure sending unit cracked and oil was leaking into bilge. Having the discharge on side with helm where I was hauling gear, let me catch it quickly and shut things down. Quick tow in and fix and were back out hauling gear in the afternoon. Never want bilge discharge where I can't see them easily
I had a nasty case out on Guam involving a boat that sank at the dock in the night. The bilge pump through-hull was located at the waterline, for cosmetic reasons. The in-line check valve failed when a small bit of bilge debris held the valve open after the pump cycled. A small wake introduced seawater. There was no anti-siphon loop. The boat sank before dawn. Constructive total loss. Hundreds of thousands of dollars. The owner was fined under the OPA ‘90 Clean Water Act over the resulting oil and diesel discharge into the harbor. Huge fine. Nasty, nasty.

For me, no bilge through-hull even near the waterline. Never rely on a check-valve to keep water out of the boat at any angle of heel or any potentially loaded condition. Also, as noted above, having the bilge discharge where the outflow can be observed while operating the boat (both for flow rate and for content, but also for frequency) is my preference. Just my two bits. Others on here are much more knowledgeable than me on this topic (and nearly every other topic).
 

Alext123

1st Mate
Joined
Oct 16, 2020
Posts
252
Likes
190
First Name
Alex
I am in the process of redoing my bilge and wondered why one of the pumps discharge was forward of the main bulkhead?
 


Top Bottom