Adding bilge discharge... thru hull location and hose run?

M

Major Tom

New member
I'm adding a backup bilge pump, and will be using 1 1/2" hose (on a Rule 3700). I've looked at several posts but am still a bit unsure as to where I want the thru hull discharge, and which fitting is best. Any advice?

I'm hesitant to simply enlarge the port laz discharge... I just use it for storage now, but down the road I may want to have a livewell. Also, it's a bit low, a little too close to the waterline for comfort. The Starboard laz has electronics; breaker, battery switches, etc. I guess that could work, but I have a nagging thought that running a water hose over electronics is a bad idea.

I'd also like to get it close under the rub rail, so it's high. There is a spot just forward of the port la zby a couple inches that might work. Has anyone done that? Wouldn't exactly line up with the port laz discharge so it wouldn't be pretty, but in this case perhaps function trumps form.

Also, what's a quality fitting, and what size? Seems like chrome plated bronze is the way to go, which will amtch the other thru hull discharges on the boat...? For example I found this Perko one, but they have 2 sizes... "regular" for up to 2", or "short" for up to 5/8". I'm guessing the regular, but I have no idea how thick the gunwales are.
http://www.hodgesmarine.com/Perko-1-1-2 ... iramsegdoh

Thanks in advance for the help!
 
Mine (which was added after build but before my ownership) is routed such that it exits on the stbd. topsides but right aft. This way it's well aft of the starboard lazarette/contents. I have re-done the through hull (from plastic to metal, which is my preference) and I added a backing block, which isn't necessary but which I just like to have.

As far as the discharge through hull height, while high is good, I wouldn't go too high. Reason is because I think it's better to have the hose be able to loop up high (under the deck) but then come back down before going out through the topsides. That way any nuisance water that may come in (from being underway, etc.), runs back out. Also, any water that ends up in the "downhill to the through hull" section is water that won't run back down into the boat (and no check valve needed - they can clog).

The "water running back into the boat after the pump stops pumping" can also be limited somewhat by using a pump that takes a smaller discharge hose size. That's a matter of personal preference, but something to consider. (On larger boats oftentimes a pump with a 3/4" hose is fitted for everyday nuisance water, for that benefit; and then a larger "crash pump" is fitted for real emergencies, with a much larger hose (but that would be a pain on a daily basis as quite a bit of water would come back after the pump stopped).

On my C-Dory, I consider both bilge pumps to be nuisance water pumps, essentially, so both of mine have 3/4" hose (and no check valve as I am not fond of them). I think I have a 1000 gph at the transom and 500 gph in the cabin (if I remember correctly). I switched all of my through hulls over to metal from plastic (again, IIRC, they are 316 stainless, but chromed bronze is good too). I prefer metal ones to plastic.

As in many things boating there are many "right ways" to set things up, and personal preference plays a part in it. (Of course there are some wrong ways too of course.)

PS: Forgot to mention the gunwale thickness. I don't think you'll find fiberglass thicker than, say, 1/4"-3/8" - and probably closer to the latter. I have measurements, but can't remember where I filed them away at the moment.
 
Tom,
Congrads, I bet you'll have the largest 'backup' 3700 gph bilge pump on any 22 CD ever.
Agree with Sunbeam's comments.
My builder had to route a fishbox macerator output over top the battery switch box, so don't feel too bad if you absolutely have to. Use best-quality smooth bore hose and chafe protection and it can be OK. (5 of my 8 water pumps are at the transom).
Best,
John
 
Thanks, guys! Sunbeam, thanks for all the detail, I always enjoy reading your posts. I agree, don't want to be too high. I've seen a few here that put it just under the rub rail, and on my boat it looks like I'll still be able to loop it. (And I've read that a good rise over the heeled waterline is quite acceptable/safe, especially for a boat like ours... but of course a loop is better.) BTW I love your mods... nice work!

John, that's good to know. I thought about that too... when done right, the odds of something leaking are pretty slim. LOL on the largest backup! How true... I was looking at 1500s and 2000s, then figured why not, the 3700 isn't much larger, still fits fine in the aft sump area, and it sort of gives me more options in routing the hose, since any flow reductions will be of little consequence. Since I've retired I've been going a bit overboard a bit on my projects!

I'll be posting pics when I finish. Thanks!
 
Nothing all that fancy about this project but thought I'd post in case someone is looking at the same thing. I ended up using the THF (through hull fitting) for the port lazarette... I don't use the live well and I hate poking holes in the boat if I can avoid it. :mrgreen:

I also ended up with a Rule 2000 (Gold, I think), mainly because the 3700 was going to take up too much space. I coupled that with a USS Mini float switch (great switch!). I mounted the 2000 just in front of the drain hole in the stern (using 4200), looped the hose and connected it to the live well THF.

Last, I installed a Johnson bilge switch (3 way) at the helm. I could have put it in the starboard lazarette (where my battery switches are) and saved a lot of wire runs, but I wanted to ensure I'd always see what position the switch was in. I also taped some spare fuses right next to the switch (and fuse), a tip I learned here... If your pump blows a fuse due to debris or whatever you want to change it fast after you cleared the pump.

While I was at it I installed a Johnson Bilge alarm (under the starboard gunnel compartment, right next to the wire hole leading into the cabin. So if I'm docked and away from the boat the alarm is hopefully more audible to the marina staff, than in the cabin.)

So now I have 2 pumps and an alarm, all separate, and all wired and fused separately to the batteries for improved redundancy. I think I put the Alarm on Battery 1 and the 2 bilge pumps on 2.

The only thing I haven't done yet is to figure out how to get fast, emergency -speed access to the pump to clear it from debris. That would also give me fast access to the drain, which would be a bonus. My 2 batteries are in between the gas tanks, in front of the pump. So I think if I just get a quick release rig on one of the battery boxes that'll do the trick. Heck, even a wingnut would be an improvement.

Regardless, I now sleep very well when on the hook! :D

Thanks for all the help!
 
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