BECAUSE I'M TO LAZY TO FIND MY PREVIOUS POST

Aug 11, 2011
859
O'day 30 313 Georgetown MD
Last year( it wasn't that long ago) I installed an low profile automatic Rule bilge pump, as my boat only had a manual pump. I routed the hose through the seat base, along one of the two water tanks, through the bulkhead base and coupled it to the head sink through hull. Roughly 12 ft. What I didn't realize is the shower floor pump (now removed due to it being broken) also used the same through hull. I'm thinking an additional through hull solely for the bilge, enabling a shorter length of hole, less traveling and maybe a little more efficient. Also as part "Deux" to the question, while I have your attention, is where should I drill the hole for the through hull? At the same level as the one for the head sink? So once again, all ye merry men and women of the sailboat owners forum, you are invited to give me your perspective on the matter and I thank you in advance.
Oh by the way, I finally got to install the auto/manual bilge switch. Do you know they sell the whole unit, provide you with three female connectors, but you have to spend extra to get a fuse.

60062412684__A8FA5883-35B7-45B3-A1D9-72DD5913E93E.JPG


I have it mounted above my DC distribution panel, but directly powered from the battery.
 
May 17, 2004
5,032
Beneteau Oceanis 37 Havre de Grace
For what it’s worth, the factory installed location for the auto bilge pump output on the Oday 28 was on the transom, port side, about a foot up. It’s the small hole just below the M -

0AC63AC8-6A2E-482B-9C7C-268561740844.jpeg


And for the understanding of other readers - the sink thru hull referenced above is a few inches above the waterline, not below as some are.
 
Last edited:
  • Helpful
Likes: Will Gilmore
Oct 22, 2014
20,995
CAL 35 Cruiser #21 moored EVERETT WA
Not knowing your boat, I will apply some Left Brain thinking to this problem.

It is a bilge pump. I want it on automatic all of the time. I am trying to lift water that is in the boat out of the boat. If the thru hull hole goes below the level of the water, the water I am trying to pump out will be coming back in. Not a good solution. = It seems that the location used by the manufacturer to empty the manual pump might be a good location to consider as it meets several of the criteria.

Triggering my Right ‘Artistic’ Brain side... I want to minimize the number of holes in the boat, they just don’t look good. I would like to make the hole disappear. Perhaps the one hole already there can do double duty for bilge pumping.

Hope my thinking can be of help.
 
  • Like
Likes: Will Gilmore

dmax

.
Jul 29, 2018
971
O'Day 35 Buzzards Bay
It's also standard practice to have a devoted hose for the bilge pump, not shared with anything else, for good reasons.
 
  • Like
Likes: eherlihy
Jan 24, 2017
666
Hunter 34 Toms River Nj
I'm thinking discharge should be as high up the hull as possible. I installed a secondary back up pump about six inches from the top of the hull. Plus a check valve.
 
May 17, 2004
5,032
Beneteau Oceanis 37 Havre de Grace
I'm thinking discharge should be as high up the hull as possible. I installed a secondary back up pump about six inches from the top of the hull. Plus a check valve.
Higher is better for preventing water ingress if the boat is sinking, but until the point where you’re sinking lower is better. Check valves can fail, especially when in dirty bilge water. If the valve fails and the discharge is too high then the same water will cycle back and forth between bilge and hose, eventually draining the battery. Also bilge pumps are quite sensitive to head height. If more than a couple feet of my transom are underwater I figure I’m going to need more serious water extraction ability anyway, so I personally prefer the lower discharge. Your boat your choice as they say I guess.
 
Jan 22, 2008
50
Oday 30 Stamford CT
I have a 1983 O'Day 30 and that has a factory installed manual bilge pump installed in the rear panel of the cockpit and the water pickup fitting for the pump is mounted in the bilge approximately 3 feet from the wall between the engine compartment and the cabin. I installed my electric bilge pump about 1 foot forward of the manual pump pickup. I then cut into the factory installed discharge line and installed a Y shaped fitting in the line so that the new electric bilge pump and the manual bilge pump can discharge through the factory installed discharge line. I also installed a check valve near the pickup for the manual pump so the water flow from the electric bilge pump does not flow back into the bilge when the electric bilge pump is running. It works an I didn't have to run an additional discharge line and overboard fitting for the electric bilge pump..
 
  • Like
Likes: Will Gilmore
Oct 2, 2008
3,807
Pearson/ 530 Strafford, NH
We didn’t have a vented loop on the bilge hose back when we had an old Catalina. Following seas / big waves / covered our stern through hull just as the pump finished a cycle. It was a perfect siphon bringing water back into the bilge at an alarming rate. The little pump couldn’t overcome the flow so got heavier and continued to sink. I saw the rug floating from the cockpit and altered course for shore 25 miles away. I used the hand pump, which had a separate hose and through hull, to keep ahead of water coming in. The new course lifted the stern just enough so the the bilge pump could reverse the incoming water and blow it back out.

That happened with pea soup fog and a wife at the helm not too happy. Our now boat has two bilge pumps, two hand pumps, and two sump pumps all with separate, vented lines. I just woke my wife up and asked if she was happy, if a knee in the crotch means yes, I think we’re good.
 
  • Like
Likes: Will Gilmore
Oct 19, 2017
7,733
O'Day 19 Littleton, NH
if a knee in the crotch means yes, I think we’re good.
Oh so many things could be said here. :kick:

I tend to favor GeorgeC's thinking. The check valve seems particularly important. I'd put that in regardless of sharing or dedicated line. If there's never going to be a need for water to flow in reverse, but the conditions for reverse flow are at all possible, do something to prevent it.

-Will (Dragonfly)
 
Jul 30, 2019
216
Seaward 25 777 Fort St. James
It was a perfect siphon bringing water back into the bilge at an alarming rate.
To show my ignorance, are there not backflow preventers that can be installed? I would think that there would be a standard fitment to prevent this eventuality. Is that what George means with his check valve? If such a preventative standard has not entered sailboat construction it must indicate a dire shortage of lawyers in the field of recreational boating liability.
 
  • Like
Likes: Will Gilmore
Oct 2, 2008
3,807
Pearson/ 530 Strafford, NH
To show my ignorance, are there not backflow preventers that can be installed? I would think that there would be a standard fitment to prevent this eventuality. Is that what George means with his check valve? If such a preventative standard has not entered sailboat construction it must indicate a dire shortage of lawyers in the field of recreational boating liability.
A check valve can get stuck in one position so a vented loop is more desirable. It’s hard to sue someone who died years ago and even harder to prove a boat wasn’t altered by an owner during the lifetime. I don’t think a lawyer would work for what I’m willing to pay. Best advice I was given was to learn my boat, been at this one for nine years and have physically touched 85% of the hull from the inside.
 
  • Like
Likes: Noodat Lady
Oct 19, 2017
7,733
O'Day 19 Littleton, NH
If such a preventative standard has not entered sailboat construction it must indicate a dire shortage of lawyers in the field of recreational boating liability.
I am absolutely certain that is not the case.

-Will (Dragonfly)