Bilge pump question

[Curious Sailor]

I have a 1973 Macgregor Venture 21' trailer sailor that I am currently restoring to put back into serviceable condition. I'm new to Sailing but have had power boats my whole life. One of the key differences I noticed with this sailboat vs other boats that I owned is the lack of a drain plug..

The cockpit has a hole to allow a path for the swing keel cable and from what I can tell, it doubles as a cockpit drain. That works fine but my concern is the cabin. Water collects in the cabin and settles towards the center of the boat. Normally I would place a bilge pump at the lower most collection point however there is a keel trunk right down the center so water collects on both sides. Then there are the stringers Forward and aft which also hold water in separate compartments of the boat.

My question is do I need multiple bilge pumps or is there another solution that someone can share. (Other than, just don't get any water in the cabin or go buy another boat..lol)

[exMaggieDrum]

I don't know your boat at all so can only say this from what you said. So take it with a large grain of salt. No one else has jumped in so.....

If if were me I would put in at least one bilge pump at the lowest of all the bilge compartments. On most boats there are limber holes in the stringers to allow water from one to flow down to the main collection point where your bilge pump would be. You might (or might not) be able to drill some limber holes in the transverse stringers to do this. If you do, use epoxy to seal the inside of the holes so water can't penetrate in to the core. That would allow those areas to drain.

If you can't drain them passively with limber holes then you will have to put in separate bilge pumps in each isolated area. I would ask myself why water is getting in to those areas first and see if that can be "fixed". There are some new very low profile bilge pumps with internal water level switches but it would be a PITA to wire and plumb all this (as you know).

Otherwise it would be sponge time as needed with all the bother that entails.

Good luck.

[Curious Sailor]

Hi exMaggie,

This one has me chewing on a block of salt let alone a grain.. Lol.
Thanks so much for the awesome input! You and I are thinking exactly along the same lines.. I've been scratching my head for awhile on this one but other than drilling through the stringers, I can not see away around a minimum of two pumps. The boat has a swing keel so the trunk that houses the keel runs right down the center from the companionway to the v-berth. Drilling through the trunk is not an option so I would at least have to get a pump on either side. As far as where and why the water is getting in, well, I will be able to mitigate that shortly. It's in the early restoration phase so there are water entrances across the top deck and the companion way hatch. It only gets wet when we have torrential down pours here in Florida... As I move forward with the restoration I will be buttoning all of the ingress points as best as I can but you know how boats are... They get wet, no matter what. Was just wondering if anyone out there has experienced the same issue, or if maybe there was some magical multi port bilge pump on the market.. Nevertheless, I will work through it. Again, thanks so much for the advice!

[exMaggieDrum]

I'm not aware of any multi-port bilge pumps. It would be tricky to not suck air when one compartment goes dry before the other one thereby screwing up the whole deal. I would want to seal your boat so that it does not get wet on a regular basis even in torrential rains. Some boats are built "open" so that water always gets in but that's not usual for most boats.

[Curious Sailor]

It's not usual... But this one is 42 years old... Who knows what Macgregor was thinking back then... I'm planning to construct my own companionway hatch so I'm hoping that would do the trick... When I bought the boat it had two holes drilled in the transom.. At first I couldn't figure it out but now I know... They didn't know how else to drain it as it sat on a trailer unloved for years.. Lol.
As for the multi-port I didn't think I would get so lucky.. my buddy suggested a self priming sump but I think that's overkill.. Would rather seal it up.

I uploaded a pic of the keel trunk to show you the separation..not sure where it's at though I'm new on this site.. Lol.. I'll figure it out

[Curious Sailor]

Ok. I see the pic after I posted the reply.. Lol. There you go

[exMaggieDrum]

If I understand you right, the two sides of the pic showing the keel are both collecting water, or, are their compartments farther forward that are also collecting water? You have plenty of room in the two sides you have in the pic for two bilge pumps. But the recommended way to discharge bilge pumps is have one thru-hull for each pump (above the water line). The problem with one is that you will pump the water from the one and then it would go down the tube from the other one so you would just be moving the water around rather than putting it overboard.

I have a similar situation and the previous owner (PO) put in check valves so the water can only flow one way, i.e water can go out on both but none can flow back down. Check valves can even be used on just one valve to make sure that water that is not completely pumped out doesn't just drain back down when the pump starts. The problem is that check valve can stick - either open or closed. Closed is bad since you can't pump out. Open is bad since it doesn't do what you want it to do.

But, another possibility is to put in two vented loops before a Tee at the thru-hull. The loops would be higher than the Tee so the water would go out rather than trying to go up the loop higher. You can look up vented loops. You need an opening at the top of each loop so a siphon is not created and backfill the boat in certain situations. This may sound like a hard thing to do but not at all if you have a place to do it. Vented loops are required for the inflow side of toilets to keep them from siphoning in water if the valves stick open. Also used on the hose taking raw water cooling from the engine before it is injected in to the engine exhaust (cools it down before it goes in to the muffler and then out).

As far as putting in limber holes in dividers - you'll have to figure that out. Sounds like you are getting this sorted out in your head

BTW - if you do do two pumps, you'll need two float switches (or built in water level sensors in the pumps) but you can probably wire them to the same supply wiring (with fuses etc.). They make some really low profile pumps now that have switches built in. Don't think you would need a really big one (unless you want to make sure that a bigger leak from the ocean doesn't sink your boat). That's what bilge pumps are for too! What you are trying to do is get rid of nuisance water from topside leaks, but you should consider the safety aspect if you had a leak below the water line, so one of the pumps could be sized big enough for that.

[Curious Sailor]

There is one more compartment forward under the berth, so essentially three areas for water collection. I'm trying to visualize the hook up you describe, but I don't think it's coming together correctly in my head. Do you happen to have photos of the set-up? I'm curious to see the vent set up.

I had imagined two bilge pumps with two independent outflow through hulls above the water line. then possibly inserting a 1" pipe drain tubes in the forward stringers to allow water to flow back to the bilges.

Thanks for your advice on this! It's very much appreciated!

How many pumps do you run in your 44?

[exMaggieDrum]

Originally Posted by Curious Sailor

There is one more compartment forward under the berth, so essentially three areas for water collection. I'm trying to visualize the hook up you describe, but I don't think it's coming together correctly in my head. Do you happen to have photos of the set-up? I'm curious to see the vent set up.

I had imagined two bilge pumps with two independent outflow through hulls above the water line. then possibly inserting a 1" pipe drain tubes in the forward stringers to allow water to flow back to the bilges.

Thanks for your advice on this! It's very much appreciated!

How many pumps do you run in your 44?

First off, I have not seen a vented loop used for two bilge pumps before but I think it would work. You would have two of them, one for each discharge hose put before a Tee where they would combine the outlet leg of the hose to go to the thru-hull, which normally for bilge pumps would be above the water line.

Here is a description and diagram of other uses though:

Vented loops and anti-siphon valves ; how they work on boats

Here is another from Forespar:

http://www.forespar.com/pdf/techTips...Loops-long.pdf

There are other brands. But the vented caps can sometimes stick so you are supposed to inspect them regularly and make sure they still work. You can even make you own vented loop with a bronze or PVC Tee and put a hose on the upper side instead of a flapper valve. That is common, and even ones that the Forespar may be modified to take the flapper off and put a small hose clamped there and lead it down to the bilge. It should normally not have any fluid in it but it keeps a siphon from being developed at the loop. You can Google vented loops and find lots of examples. The ready made ones are nice because they have a nice radius which is better through put without sharp bends.

My current boat has an abnormal setup. There are two diaphragm pumps, both above the bilge. There is one pickup hose to the bilge (for bilge water) that goes to a three-way valve which is connected to another three-way valve on one side, and to the "main" bilge pump. The other pump goes to a second three-way valve which goes to a pickup in a gray-water tank and the other side of the valve goes to the other valve, so both valves are connected. The outputs of both pumps share a thru-hull and there are two check-valves in each of those hoses so that one pump does not pump back in to the bilge or gray-water tank. A diagram is below.

There is also a small bilge pump to take any water that gets in the bow chain locker and it outputs to the bilge where it goes out with the other bilge water (if any).

It is what came on the boat. I do not like the check valves because (a) they can stick open if not kept clean and (b) they don't close 100% all the time allowing some leakage. There are ones that close 100% but they jam easier. So it is a compromise. The system is good in that each pump can pump out the bilge or the gray-water by changing the three way valves. It is a bit complicated which was the theme of the PO. I am going through and simplifying as many things as I can but will leave this as is for now. I redid everything though and put in new hoses, relocated the pumps to shorten hoses and get rid of kinks and bends. I also put in new water sensors for the bilge and a separate alarm circuit that is higher than the bilge water level sensor to activate the pump. If I use the gray-water pump I have to turn it on at the panel after I set the valves correctly.

I am having trouble uploading the PDF of my diagram. I'll try another way.
(It is too big for the forum upload limits and I don't know how to shrink a PDF file. Send me your email if you want it and I'll send it by that.)

[Curious Sailor]

Wow! Awesome info.. You learn something new everyday! Thanks for teaching.
I had never seen those vented loops before but it makes all the sense in the world now. And yes I'm already sketching and thinking about making my own.. Lol

My e-mail is cursailor@gmail.com