Bilges compartments

[Lou_tribal]

Hello,
First my apologizes if I do not use the correct terms so correct me if it is the case.
On my boat I have 4 bilge compartments, from stern to bow:

• One crossed by the shaft where the shaft seal is dripping.
• The engine room.
• One just forward the engine room.
• And finally another one from which I can access the bow thruster electric motor.

All these compartment are separated by a wall, originally with a hole at the bottom that communicate from one to the other.
The PO closed the hole from the more aft to the ER as he did not want any water from the shaft seal to come in the ER.

My question is: Should all these compartment communicate to each other or should they be isolated? I see pro and con to either one so my question.

Thank you!

L.

 

[Lepke]

Usually each separate area has a bilge pump but also the limber hole is kept open so any water travels to the lowest point in the hull. The hole is usually small so any major leak can be contained in that bilge area without flooding the whole boat.
If your shaft seal is leaking while stopped, it either needs adjustment or repacking. Many older housings have a grease fitting so waterproof grease can help lube and seal the shaft. Normal oldstyle seals are adjusted so the shaft drips slightly when running, but doesn't drip when stopped.

 

[RT Firefly]

Greetings,
Mr. L_t. As Mr. L notes, bilge compartments are usually connected so water can drain to the lowest point and then be pumped out. As well as adjusting your shaft seal, perhaps fore and aft trim is not ideal for the best/lowest pumping arrangement.

 

[dhays]

The only caution I would add is that if there is not a pan under the engine to catch or or fuel spills/leaks, the PO may have separated that compartment to avoid unintentional overboard pumping of oil.

 

[Lou_tribal]

Mr Lepke, Mr RTF, thank you both!
My seal is fine, one drop per 10/15 second while underway and 0 to 2 drop every 5 minutes while stopped, except when we put the boat back in the water and the packing is dry when it will drip a bit more during the time the packing needs to take its place. On that side it should be ok.
Currently I have 2 bilge pumps one small (800gph) automatic in the aft bilge for the water coming from the shaft seal and one bigger (1500gph) manual in the ER. I want to add a second in the ER (in case, just for good measure, 3500Gph). there is none in the 2 forward compartments. I have another small 700 Gph used to remove water from the cooler but this one is not a "bilge" pump as not in the bilge.
I was thinking that in a way it is good to have hole connecting the compartments but in another it was maybe better to isolate them with a pump in each and a hole, a bit higher as an overflow, just in case the pump in this compartment fails.

But as usually I think I am overseeing all this!

L

 

[RT Firefly]

Greetings,
Mr. L_t. Mr. dh makes an excellent point regarding oil/fuel in the bilge. Do you have a drip pan under the engine that would contain any leakage?

 

[Lou_tribal]

No drip pan but pads that capture only oil but not water that I change regularly. Indeed I would not want to see any oil pumped overboard.
Another thing I need to change regarding the aft bilge is that currently my shower water is ending in it and the bilge pump pumping it overboard. I do not like this at all as it make a mess in that bilge. I need to fit a sump box in some way. One more thing on my list of todo.

L.

 

[Rossland]

Lou, no need to apologize . Your English is a lot better than my French.

My boat also has four bilge compartments, each with its own bilge pump. But they are not connected. I prefer it that way.

 

[Steve]

On mine the section under the engine has no holes. I understand it is like that to avoid pumping oil overboard in case of a leak

 

[Comodave]

I prefer to have at least the engine room separate from the other bilge spaces. If you have an oil leak it will be contained in the engine room and not spread all the way to the bow. If you do separate the bilge into areas, then you do need to have a pump in each section big enough to deal with any possible bilge water. My last boat had limber holes throughout the whole boat. It had oil residue under the vee berth. I closed up the limber hole in the front of the engine room and spent many hours cleaning the entire bilge and then painting it white. Something that the PO apparently didn't care about...

 

[Lou_tribal]

I prefer to have at least the engine room separate from the other bilge spaces. If you have an oil leak it will be contained in the engine room and not spread all the way to the bow. If you do separate the bilge into areas, then you do need to have a pump in each section big enough to deal with any possible bilge water. My last boat had limber holes throughout the whole boat. It had oil residue under the vee berth. I closed up the limber hole in the front of the engine room and spent many hours cleaning the entire bilge and then painting it white. Something that the PO apparently didn't care about...

Was your PO the same as mine?

 

[Lou_tribal]

Speaking of bilge pump I just finished to clean the one that was in my aft bilge. It is a rule 800 gph with external float switch. It was working but soooooo dirty. Now I know that the pump as well as the float switch can be teared apart in small pieces easy to clean. Motor, housing and grid for the pump, support, hinge and floater for the switch.
1.5h later at cleaning everything with hertel it is like new!

L.

 

[S41]

I have three separate bilge areas in my boat. Forward, engine room, & aft. All are sealed from each other up to the floor boards. Each has it's own bilge pump and high water alarms. Plus, both the forward and aft bilge areas have a shower sump that is open on the top. So, if the main bilge pump in that area can't keep up with in flowing of water, once the water hits 12" high, it will flow into the shower sump and that will also pump out the water. Each bilge pump is 1000 GPH. Total of 6 on the boat. 2 in each bilge area (counting the shower sumps).

There are no limber holes between the separate bilge areas. Although, there a quite a few wire holes, plumbing holes, exhaust holes between them which are all high up in the bulkheads, close to the cabin floors

 

[Lou_tribal]

I can see the potential utility of a hole placed on the high side as an overflow in case the pump in a compartment fails so water can overflow in the next compartment t be pumped overboard. On the other side if the compartment is really watertight then it i another story but I do not think pleasure boat have watertight compartment, well at least not mine.
Good matter for thinking

L.

 

[dhays]

Speaking of bilge pump I just finished to clean the one that was in my aft bilge. It is a rule 800 gph with external float switch. It was working but soooooo dirty. Now I know that the pump as well as the float switch can be teared apart in small pieces easy to clean. Motor, housing and grid for the pump, support, hinge and floater for the switch.
1.5h later at cleaning everything with hertel it is like new!

L.

Your idea of creating a separate sump for your shower drain is a good idea. Bilge pumps, at least in my mind, are there to keep water on the outside. You want to be sure that the aft pump that is near your shaft seal is always in very good working order in case something goes very wrong. If it is getting dirty from the shower (hair, soap scum, etc...) then it may be be up to the task of pumping at full capacity when it is needed the most.

My sailboat had a sump in the shower floor that was pumped directly through a thruhull. My current boat has a drain that goes into a water-tight box on the floor of the bilge with its own pump and float switch. This box is then pumped out using its own thruhull. This keeps the bilge pump free to do its own job and keeps the bilge cleaner.

Also a good idea to periodically take a wet-dry vac and vacuum the bilge to get out debri, dust, dirt etc...

 

[Lou_tribal]

Your idea of creating a separate sump for your shower drain is a good idea. Bilge pumps, at least in my mind, are there to keep water on the outside. You want to be sure that the aft pump that is near your shaft seal is always in very good working order in case something goes very wrong. If it is getting dirty from the shower (hair, soap scum, etc...) then it may be be up to the task of pumping at full capacity when it is needed the most.

My sailboat had a sump in the shower floor that was pumped directly through a thruhull. My current boat has a drain that goes into a water-tight box on the floor of the bilge with its own pump and float switch. This box is then pumped out using its own thruhull. This keeps the bilge pump free to do its own job and keeps the bilge cleaner.

Also a good idea to periodically take a wet-dry vac and vacuum the bilge to get out debri, dust, dirt etc...

Totally agree, moreover having the shower using the bilge for me is having an open sump aboard as the pump will never be able to dry the bilge totally. Not very clean in my sense.

L.

 

[FF]

"Do you have a drip pan under the engine that would contain any leakage?"

Plan B is to do what the commercials with too much machinery to isolate each source of an oily drip, is to have a filter pack that removes the oil before it goes overboard.