Hull Drainage Question

[paulsdunford]

Hi

 

I just bought a 2002 Dave Clark built narrow boat. There's a leak coming from the flue which is causing some staining and dripping inside the cabin when it rains. The floor seems to be OK, and no wood on the walls is swollen - just stained. I'll address the leak (once I can find the source) but I wondered if the water that runs down behind the inner walls can find its way into the hull and, if it can, is there any way to drain it?

 

Logic tells me the hull should be designed to let any water that finds its way into the hull run to the back to be pumped out from the bilge pump in the engine compartment, but I am not sure how good this logic is in practice. I'm just imagining a sealed compartment in the middle of the boat filling up with water and never draining. I hope I'm wrong and would love it if someone can give me a clue how hulls are designed to handle leaks into the mid-sections.

 

Thanks in anticipation. There sure is a lot to learn!

 

Paul

 

 

[blackrose]

You should have an inspection hatch in the floor at the back of the cabin. If you haven't then you can cut one yourself and pull out some ballast.

Edited August 14, 2015 by blackrose

[Joe Bourke]

Water getting under the floor in the cabin shouldn't be able to get into the engine space, or vice versa. You need to be able to see under the floor somewhere near the engine/cabin bulkhead, and have the means to get any water that will drain to that area out. A hole for an wet/dry Hoover should be made in a discrete place for just that. If your water tank is fairly empty, there will be a good slope, bow to stern for any water to drain that way.

[paulsdunford]

Thanks for the help all/ Much appreciate. More investigation required I think. I'll have to start looking under beds and furniture to see if any inspection hatches are already present.

 

Just beginning to realise how awkward it is for DIY things on a narrowboat when you don't live on it and have to keep travelling to it with tools from home!

 

Cheers

 

Paul

[frahkn]

Thanks for the help all/ Much appreciate. More investigation required I think. I'll have to start looking under beds and furniture to see if any inspection hatches are already present.

 

Just beginning to realise how awkward it is for DIY things on a narrowboat when you don't live on it and have to keep travelling to it with tools from home!

 

Cheers

 

Paul

 

Paul,

 

Inspection hatches are often in cupboards or wardrobes but there may not be one.

 

There isn't in my Orion built tug and making one is difficult because some maniac has fitted a quarry tile floor throughout!

 

Frank.

[David Mack]

Hi

 

I just bought a 2002 Dave Clark built narrow boat. There's a leak coming from the flue which is causing some staining and dripping inside the cabin when it rains. The floor seems to be OK, and no wood on the walls is swollen - just stained. I'll address the leak (once I can find the source) but I wondered if the water that runs down behind the inner walls can find its way into the hull and, if it can, is there any way to drain it?

 

Logic tells me the hull should be designed to let any water that finds its way into the hull run to the back to be pumped out from the bilge pump in the engine compartment, but I am not sure how good this logic is in practice. I'm just imagining a sealed compartment in the middle of the boat filling up with water and never draining. I hope I'm wrong and would love it if someone can give me a clue how hulls are designed to handle leaks into the mid-sections.

 

Thanks in anticipation. There sure is a lot to learn!

 

Paul

 

 

 

There's no single answer. Older boats had a continuous bilge, so water would generally find its way to the back of the boat. On newer boats the back bulkhead of the cabin generally carries on right down to the bottom plate, so the cabin bilge and engine bilge are separate. As others have said, an inspection hatch just inside the cabin is advisable so you can inspect and empty the cabin bilge.

 

All of this assumes that there are cutouts (limber holes) at the ends of transverse frames on the bottom plate to allow the water to flow through. Occasionally these may not be present, or may be blocked by rust or other debris, so water may not always flow back. Similarly, on boats with loose concrete or brick ballast sitting directly on the bottom plate it can take a surprisingly long time for any water to make its way back. And it your boat is ballasted to sit level (or nearly so) in the water there won't be much flow.

 

It may be necessary to add some weight to the back of the boat and empty your water tank (if in the bow) to maximise the fall, and check over a week or two or longer to see if water is still working its way towards the stern.

[blackrose]

Thanks for the help all/ Much appreciate. More investigation required I think. I'll have to start looking under beds and furniture to see if any inspection hatches are already present.

 

Just beginning to realise how awkward it is for DIY things on a narrowboat when you don't live on it and have to keep travelling to it with tools from home!

 

Cheers

 

Paul

If you've got some steps at the back of the cabin it may be under there.

 

If you have to cut a hatch then just forward of the bulkhead is ideal. In other positions further forward you won't get maximum drainage and you'll have to watch out for floor bearers.

 

The easiest way to cut the hatch is drill 4 holes in a square between the area supported by the floor bearers, and then join them with a jigsaw, or use a multi tool. I had to snap a jigsaw blade in half as it was too long and kept hitting the ballast Underneath. A jigsaw that cuts at an angle can be used and then you can just sit the lid you cut out back over the hole.

 

If you find that the lumps of ballast (assuming broken concrete) are too large to get out of the hatch you've cut, you will need to use a cold chisel and lump hammer to break it up. This is when you need know that your base plate is not wafer thin! Don't forget your eye protection.

Edited August 14, 2015 by blackrose