Engine bilge sump

[Chowny]

Good day,

As a catamaran sailor who is thinking of retiring to a narrow boat, I have been looking at websites, vlogs etc and wondering why narrowboats don't seam to have a sump in the engine bay to drain the water into for the bildge pump to pump out?  It would only need to be a couple of inches and would, I would think stop alot of rust problems in the engine bay. I would be interested to know any thoughts. Thanks

[nbfiresprite]

Many narrowboats do have a sump under the prop shaft for the bilge pump. Lack of maintenance is the main cause of rust.

[Tony Brooks]

5 hours ago, Chowny said:

Good day,

As a catamaran sailor who is thinking of retiring to a narrow boat, I have been looking at websites, vlogs etc and wondering why narrowboats don't seam to have a sump in the engine bay to drain the water into for the bildge pump to pump out?  It would only need to be a couple of inches and would, I would think stop alot of rust problems in the engine bay. I would be interested to know any thoughts. Thanks

 

You need to distinguish between the engine drip tray that is mandatory and is usually formed by the engine beds, bulkhead and plate across the back of it under the gearbox coupling and the bilge. The bilge is typically formed by the curves sides of the stern swim and the aft bulkhead.  The drip tray is usually well over two inches high and must never have a bilge pump in it because it is required to contain drips and spills of oil, fuel and antifreeze. The aft bilge is typically in three sections that are joined. One on each side of the engine formed by the bed, swim plate and bulkhead and a smaller triangular one formed by the swim plates and the plate that forms the back of the engine drip tray. Some builders cut a rectangular hole through the baseplate sealed by the skeg welded to the outside. This forms a small sump area for the bilge pump.

 

Some rear engine room narrowboats leak rain etc into the area to some degree while others remain dry. In the latter case boaters often put the bilge pump is a small container located in the triangular section under the stern gland to keep the  rest of the bilge dry.

 

Most modern narrowboats have a separate rear engine room bilge and accommodation bilge whereas many old ones have a through bilge much like yachts & cruisers.

[Tracy D'arth]

Piper Boats shells have a circular sump in the stern triangle under the shaft.

[Alway Swilby]

Our old share boat built by Elton Moss had a round sump under the prop shaft.

[Sea Dog]

1 hour ago, Tracy D'arth said:

Piper Boats shells have a circular sump in the stern triangle under the shaft.

Mine doesn't Tracy, but mine's a Simon - was it a David thing? 

 

I have the usual triangle aft with cut outs to the port and starboard swim bilges as described in @Tony BrooksBrooks excellent advice above. Instead of the circle, I have placed a plastic mushroom container to catch any drips from my stern seal. As it's a Volvo seal (as found in many yachts and perhaps familiar to the OP) there are no drips, so it's really no more than a tell-tale and the bilges of my trad stern boat are perpetually dry. Not all narrowboat bilges are created equal @Chowny,  so there's more to it than you've seen so far. Some forward well decks drain the length of older boats to be pumped out at the engine bilge, many cruiser sterns leak rainwater into the engine space, etc. Since it's an area you already have ideas about, you will get benefit from further research. 

 

I'm familiar with the little sump in yachts you refer to. I think the lack of this otherwise desirable feature is down to the baseplate being typically 10mm steel, not so easy to set a little sump into and, being absolutely flat, there no low spot to site it for the water to run down to. Different to a Vee hull that you're used to, but the more you look the more of these quirks you will find in Narrowboat builds and fit outs. There is also plenty of read-across though, so your experience is not entirely wasted! 

 

 

[OldGoat]

When I ordered my hull, I went to a proper shell builder of 'the old school' who knew what he was doing.

He didn't like my for deck dimensions

He wasn't over keen about my eliptical stern

(both were too long to make the boat look 'proper' - so he won..

 

When it came to the engine bay, I just gave him the domensions of the Beta engine with all the go fasterbits at the front end.

There was no discussion about the prop shaft bilge - he just quietly left a gap either side of the engine sump tray, which left a lot of room for water to accumulate, meaning that I don't have to be pumping the bilge ad nauseam.

 

There aren't many of his ilk left, sadly....

[Laurie Booth]

9 hours ago, Chowny said:

Good day,

As a catamaran sailor who is thinking of retiring to a narrow boat, I have been looking at websites, vlogs etc and wondering why narrowboats don't seam to have a sump in the engine bay to drain the water into for the bildge pump to pump out?  It would only need to be a couple of inches and would, I would think stop alot of rust problems in the engine bay. I would be interested to know any thoughts. Thanks

I have a washing up bowl with the bilge pump in it.

[Big Bob W]

4 hours ago, Tony Brooks said:

boaters often put the bilge pump is a small container located in the triangular section under the stern gland to keep the  rest of the bilge dry.

An old plastic ice-cream tub in our case. Wall's Soft Scoop works best I think! 

[Ex Brummie]

6 hours ago, Big Bob W said:

An old plastic ice-cream tub in our case. Wall's Soft Scoop works best I think! 

A good stern gland doesn't leak. Aqua drive is such a boon.

[Chowny]

Thanks for all the information. Inquiring mind sorted. I especially like the icecream tub idea as I could experiment with different flavors.

[Chowny]

3 hours ago, Ex Brummie said:

A good stern gland doesn't leak. Aqua drive is such a boon.

Yes I have 2 of those on board and had very few problems in the last 7 years.....touch wood