Throughways in engine room bulkhead?! (and no ballast in cabin bilges?)

[Tiboo]

Hi there,

I'm doing a job for a client, who has a whole lively forest down in their cabin bilges, living in the ideal ecosystem of water and rotten plywood. Some inspection turned out there are throughways at the corners of the engine room bulkhead..!? (And a leaky stern gland and a defect bilge pump, of course...). But.. holes there..? Does that subscribe to any boat-building practice..?

Further, I didn't see any ballast in the cabin bilges... again, could that be normal in any way..?

K

[Tracy D'arth]

2 minutes ago, Njiruk said:

Hi there,

I'm doing a job for a client, who has a whole lively forest down in their cabin bilges, living in the ideal ecosystem of water and rotten plywood. Some inspection turned out there are throughways at the corners of the engine room bulkhead..!? (And a leaky stern gland and a defect bilge pump, of course...). But.. holes there..? Does that subscribe to any boat-building practice..?

Further, I didn't see any ballast in the cabin bilges... again, could that be normal in any way..?

K

Type and make of boat?

Many older canal boats, Harborough for one, had wet bilges, some with pipes through to drain the front deck to the stern bilge pump.

[Jen-in-Wellies]

No extra ballast in the engine area is normal. The engine is usually plenty heavy enough. 

 

[Tony Brooks]

Holes designed to allow water to drain through frames and bulkheads are known as limber holes and are a perfectly normal aspect  of boat building in general. It is only in maybe the last 40 years that inland practice has been to seal the cabin bilge from the engine bilge. Before then it was not uncommon to drain the front well deck through the cabin bilge into the engine area for the bilge pump to deal with. Ditto shower trays draining into the bilge. As most narrowboats tend to sit a little bow up all in one bilges (with a working bilge pump) is not as bad as it may seem but no longer common inland practice.

[Sir Percy]

I've got limber holes, not in the engine room bulkhead, but at either end of the angles welded to the baseplate on either side of the keelson in fore and aft cabins. No ballast in the engine room.

[WotEver]

1 hour ago, Sir Percy said:

No ballast in the engine room.

I found a big lump of concrete in the engine compartment on one of the swims. So I removed it. Then I wondered why the boat had acquired a list. So I put it back. 

[Sir Percy]

On 19/08/2020 at 14:47, WotEver said:

I found a big lump of concrete in the engine compartment on one of the swims. So I removed it. Then I wondered why the boat had acquired a list. So I put it back. 

Nice bit of experimental calibration.

[Tiboo]

On 19/08/2020 at 12:01, Tony Brooks said:

Holes designed to allow water to drain through frames and bulkheads are known as limber holes and are a perfectly normal aspect  of boat building in general. It is only in maybe the last 40 years that inland practice has been to seal the cabin bilge from the engine bilge. Before then it was not uncommon to drain the front well deck through the cabin bilge into the engine area for the bilge pump to deal with. Ditto shower trays draining into the bilge. As most narrowboats tend to sit a little bow up all in one bilges (with a working bilge pump) is not as bad as it may seem but no longer common inland practice.

Thanks for that nice bit of background.

Now, I wonder if it would be beneficial or rather to be avoided to close off these limber holes, as now it literally is wet underneath all the time, as the rain gets in via the stern outside floor (at the bow too, but there is a cover..) And there is a second bilge pump in the cabin bilges anyway. Would it not be better for the hull, the plywood under-floor and the people's health on-board to have them dry most of the time..? 

Edited August 22, 2020 by Njiruk

[Tracy D'arth]

38 minutes ago, Njiruk said:

Thanks for that nice bit of background.

Now, I wonder if it would be beneficial or rather to be avoided to close off these limber holes, as now it literally is wet underneath all the time, as the rain gets in via the stern outside floor (at the bow too, but there is a cover..) And there is a second bilge pump in the cabin bilges anyway. Would it not be better for the hull, the plywood under-floor and the people's health on-board to have them dry most of the time..? 

Er, yes. 

Could that be why newer boats are dry bilge?

Front decks are raised these days so that they are self draining. 

Rear decks on semi trads and cruisers need detailed work on drain channels to avoid engine room flooding and sinking.

Never rely on a bilge pump, they are only guaranteed to work when you don't need them.

[Tony Brooks]

2 hours ago, Njiruk said:

Thanks for that nice bit of background.

Now, I wonder if it would be beneficial or rather to be avoided to close off these limber holes, as now it literally is wet underneath all the time, as the rain gets in via the stern outside floor (at the bow too, but there is a cover..) And there is a second bilge pump in the cabin bilges anyway. Would it not be better for the hull, the plywood under-floor and the people's health on-board to have them dry most of the time..? 

Unless you do a lot of work to make the front well deck self draining OR pipe between the limber holes in the front bulkhead to the same at the rear bulkhead and find a way of keeping them clear I think that despite the cover blocking the holes is asking for even more internal hull corrosion.

 

As Tracy said you need to look at making the rear cockpit decking self draining (to a degree) but I suspect this is  a very old boat and it may not be easily done.

 

If you ensure the boat trims down by the stern then any water will concentrate in the engine bay area so it can be pumped out.  It should not be a major problem as long as the boat is visited regularly and not left for moth on end unattended. Even if an auto-bilge pump failed I doubt for much of the year you would find more than a couple of inches of water in the bilge.

 

Having a wet bilge under the accommodation used to be pretty much standard on motor cruisers and yachts. If the plywood flooring is getting wet I would suggests either the boat has been badly neglected or it is sitting too close to the hull.

 

I suppose you could seal the holes in the front and back bulkhead and install another bilge pump for the front well deck area.

 

[David Mack]

8 minutes ago, Tony Brooks said:

 

I suppose you could seal the holes in the front and back bulkhead and install another bilge pump for the front well deck area.

This is what Belfast has, with solid bulkheads at the front of the conversion and front and back of engine room. So there are 4 separate bilges - front well, cabin, engine room, back cabin. The main cabin bilge is always bone dry.