You might want to consider isolating your cabin bilge from your cockpit bilge...
I use a 4" Beckson screw in inspection port that allows the two bilges to be re-connected if necessary. 3 bilge pumps, one forward, one amidships, & one aft. All 2000 gph.
This design keeps stinky cockpit bilge water from the interior spaces. No oils, fish blood, or other smelly crap inside.
I made a large "handle" for the screw in plate to make it very easy to spin it open in a rush...
Right now I have the thru hull for the head between the engines along with the holding tank and tank discharge. The batteries are located port side of motors. Gin pole mounted On starboard shelf. No bilge pump in center, running two, one forward and aft. No gen set. Sea cocks for motors with internal strainers are wedged between shaft logs and gas tank.
It will be a lot of work and my current thought process would be to put this all in the plans including sealing off the bilge during a repower.
i follow capt patrick`s forward cabin isolation when i build the boat. excellent idea cabin bilge always clean and in case of hitting a large object with bow ,as you would assume going forward the forward bilge pump on at 2000 gph. would give me more precious time to engage crash valves and start generator with heavy duty 110volt pump BEFORE water goes over batteries/ starter motor 12volt connection. 1 minute more is enough for may day by radio,set off eperb and have mate break out life raft. one idea i want to add to capt. patrick`s line of wisdom is to have a small 500gph bilge pump just in front of fuel tank bulkhead with large pump mounted on azak 2" above . this is the lowest water collection point on 31 bertram as she sit in the water so you use little pump to pull out rain water and washing down boat much better to recycle small pump set as low as possible . stern has two 2000gph pumps set at differant heights and all pumps isolated electrically from port battery,starboard battery and house battery bank . bilge pumps can run many hours on four isolated batteries.
Then you are running 4 pumps including he 500 GPH?. Are you using 4 discharge points? I would think that two 2000 GPH in the stern, one 2000 in the center between the engines and then one in the bow would do it. Add the 500 GPH tht would give you 5 with each one having it's own point of exit.
tony the 500 gph is combine with one of the stern 2000 with a wye and check valve . the thru hulls are 11/2" just under gunwale at stern on both sides.the 500 does 98% of the day to day pumping mainly when washing the cockpit deck or using the salt water wash down at sea. perfect solution to bilge pump application with 500 picking up within 1/2" of water level in lowest area in bilge.this is a photo of stern set up with two level pumping with seperate power and output .
use threaded collars from output pipe to bilge pump output flange with check valve in each pump and discharge under gunwale. if water is above this point boat is going to the bottom.
I have always been told that check valves in line are not a good idea. I realize it keeps the water from flowing back, but have heard they can clog and block up the line.
tony you are absolutely right but this forum is 31 bertram people whom have pride in there boat . needless to say our 31 bertram bilge area does not look like a garbage skow so getting the one way flapper on the check valve clog would be much less likely if it went thru the much smaller screen fins of the bilge pump itself another words the bilge pump would clog first look at the picture of the bilge at the stern does it look like there is anything to clog bilge pumps! i never have rags,fishing line,fish scales, or anything else that should not be there and hose it down when i come to dock therefore run fresh water thru bilge pumps . the forward bilge i open the the floor board and lift level switch to turn on forward pumps or hit manual and listen to each pump it takes but a second.
Flapper check valves are the only style that should be used on a bilge system... The spring style are even banned for use in bilge systems by the USCG.
Hatteras used to use a marine grade flapper check valve that was very expensive and hard to find. Last year I discovered a clear PVC flapper valve made by King Brothers in California that is the best I've seen and used. Beats the ones Hatteras used hand down.
BTW, there is one potential down side to these valves...
With no check valve, the bilge line self drains and poses no problem from freezing. With a check valve, the trapped water in the line will be subjected to freezing and can rupture the valve housing. If you're using these valves be sure to include them into your winterizing schedule...
capt. patrick the bronze check valve i use have a 3/8" drain plug on them and no spring just a one way flapper with stop . i will try to photo the ones used on the 510 Bertram.does not appear to have name but used on every hose going to a thru hull . possibly could be the ones you mention for Hatteras .cylinder style in shape and white in color with arrow for direction of flow ,but no other writing.
I always just put a loop in the hose that was fastened up under the gunnel with a pipe strap. Has worked fine for years. a little more head for the pump, but there is nothing to fail and it is self draining.
I consider my bilge pretty clean. Except for the occasional screw, nut or whatever I drop and can not get at. The problem I have is that the neighbor across the lagoon has a bunch of trees and in a NE wind, I get a bunch of them in the cockpit. Pain in the but. Just shop vacumed a bunch out of the bilge this past weekend. But you are right not much to flow through those strainers.
The navy I served in had provisions to use every engine on board as an emergency bilge pump... However, their setup was somewhat different from the one shown in this diagram...
Basically it's similar but the difference is that they don't have a "crash valve"... Instead, they have 2 way "T" valve which acts as a selector valve... You either draw water from the thru hull or you draw water from the internal scoop...
You may think it's a minor difference but think about it... It makes switching over to "emergency bilge pump mode" a single action... Turn the one single selector valve and you're done... The "dry" running time is practically nil and there's no "proper" series of actions to follow... In addition, remove a safety on the selector valve, and now you've got a scuttling valve...
Rawleigh wrote:Nav: Groco makes a seacock with that feature built into it. Very nice. They are what I use.
Rawleigh
The ones with the plug on the side correct? I have those. Sometimes getting that plug to turn out is a pain in the you know what. I have one that is stiff and it gives me fits, no matter what I do to it.
Not sure if that plug will suck as much water as a 1.5 or 2 inch hose.
True, but you can also get a hose nipple that goes in the port so you can leave it hooked up permanently and avoid the sticking plug problem. There may be some reduction in flow, but you have to look at what size your engine driven pump is too. On my 440's the pump isn't that big, so I don't know if I would benefit from a larger hose. Now on a big diesel it might. I sure hope I never find out!
Rawleigh wrote:True, but you can also get a hose nipple that goes in the port so you can leave it hooked up permanently and avoid the sticking plug problem. There may be some reduction in flow, but you have to look at what size your engine driven pump is too. On my 440's the pump isn't that big, so I don't know if I would benefit from a larger hose. Now on a big diesel it might. I sure hope I never find out!
If your 440 pump is like mine, 1-1/4 hose, single pocket with 6-1/2" pulley like crank, it is rated at 30gpm at 3000rpm, 20gpm @ 2000 and 10gpm @1000rpm.
I will have to check the pump flow rate on the Cummins.
The hose is 3/4 inch and I know I can empty a 20 gallon bucket at idle in a few minutes. I will double check the flow rate in the spring when I crank them over before going in. Fill the can and time how long to empty at idle.
Issue is if you need them because you really need them, that opening will not let you pump much above idle on the Cummins.
