Drilling all the holes in the hull

[michaelR]

Hi,

 

Firstly thanks to all the help RE: my T&G ceiling issues- I ended up taking it all down myself and refitting it, looks great to be honest but it took forever sanding off all the glue the boat fitter had used!

 

I'm now starting to fit all the plumbing stuff I've got for the boat, all recommended and supplied by Loomtech so its decent stuff :-)

 

I'm OK with the fitting of the Stainless Steel water tank under the front deck- 2 holes in the front deck, one for the water inlet and a second for the breather.

 

I then have external holes to drill for the galley outlet pump for the Belfast sink and washing machine - I assume that its OK to use one pump and one skin fitting?

 

Bathroom outlet water pump and skin fitting for the bath and hand basin, again I'm assuming one outlet will be fine?

 

Bilge pump in the engine bay, seems straightforward enough?

 

Questions I have are :- how far above the water line would you drill the holes for the galley, bilge pump and bathroom?

 

Do you use non-return valves on the skin fittings?

 

I was going to put the waste pump out on the gun whales(hope I've got that right)??

 

Lastly, would you fit an outlet/breather on the expansion tank for the hot water cylinder?

 

Thanks for all the help you've provided so far, trust me there's more requests coming?

[Chalky]

You don't need to pump the water out of the belfast sink - it should be high enough not to need it. I used a right angle fitting from the chandler, a piece of large bore hose and then connected it to the skin fitting. The skin fitting was drilled through the hull and I fitted a large bore valve on the inside so I can close it if necessary. If you can place items high enough so you don't need to pump them - pumps cost and they have a habit of clogging (usually when the shower is full of water!)

 

Personally I'd connect one outlet to one skin fitting. If two or more pipes are connected there the potential for water to go the wrong way and flood the boat.

 

I have no non-return valves on any skin fittings. I have fitted sea cocks on all of them.

 

No idea about pump out - we have a proper toilet (tin hat on)!

 

The hot water cylinder (calorifier) is usually pressurised by the water pump and will have a safety valve (PRV) to prevent it exploding. This is different from a typical domestic installation. You can plumb this in in several ways.

1 - run a pipe from the PRV into the bilge and let the bilge pump deal with it. Seems a great idea since you can see if its weeping however... If the PRV doesn't seal properly and you forget to turn the bilge pump to automatic you'll flood the compartment that contains the cylinder (ask me how I know!)

2 - connect the PRV outlet to a skin fitting.

[nicknorman]

This is how our boat is fitted (by a well established boatbuilder):

 

washbasin, direct to a skin fitting, drains by gravity

 

Shower: used to go to one of those sump boxes with float switch/pump, but they are horrid so I replaced it with a whale gulper - much better. It goes to its own skin fitting.

 

Sink: direct to skin fitting, drains by gravity. Washing machine is also Td into this skin fitting and so far no problem with washing water coming up the sink!

 

Toilet: our vent and pump out fittings are on the roof. This had the advantage of being easier to get to if the boat has its wrong side to the pump out facility (saves hanging off the gunnels over the water). It has the disadvantage of taking up a little bit of wardrobe space to accommodate the pipes, and increases the length of potentially stinky pipe. Take your pick.

 

PRV: exits into the stern gland area, but an external skin fitting would probably be a better way to do it.

[ditchcrawler]

A Belfast can be quite deep so a lot depends how much freeboard your boat has. If its a deep boat and low on freeboard the bottom of the sink could come very close to the waterline.

[bottle]

Our set up similar to most others.

 

Kitchen sink, no trap, 90° bend direct to skin fitting.

 

Washing machine to its own skin fitting, this has to be above the top water level in the machine.

 

Bathroom basin, has trap (it was supplied with basin) but still goes direct to skin fitting.

 

Shower, shower trap direct to 'Gulper' and then skin fitting.

 

Calorifier relief valve direct to skin fitting.

 

All skin fittings are as high as possible above the water line but designed to allow self drainage, except the shower.

[trackman]

My PRV vents into the adjoining engine room. To stop the bilge beneath the engine getting wet if it vents, the pipe is dipped into a 2l plastic drinking water bottle.

Handily this fits just nicely so that the pipe holds the bottle upright, but the bottle can be removed easily for emptying.

Normally the bottle stays dry, but if not I usually spot and empty any water when doing daily engine checks, before the thing overflows.

Our PRV only dribbles if the expansion vessel on the calorifier hot outlet pipe loses pressure. This happens periodically, letting the pressure of the hot water in the calorifier rise too high as the engine gets it really hot.

Pumping the EV pressure back with a tyre pump to slightly above the water pump cut-off pressure resolves this.

The EV's main purpose is to absorb the expanding water and protect the calorifier from damage that the extra pressure might cause. Very necessary this, our first had no EV fitted and split after a few years use. It was a costly, messy and difficult job replacing it!

[David Mack]

A Belfast can be quite deep so a lot depends how much freeboard your boat has. If its a deep boat and low on freeboard the bottom of the sink could come very close to the waterline.

 

But its the height from water level to the top of the sink which matters in terms safe freeboard, and that is determined by the worktop height rather than the sink depth. You could always fit a non return valve (flap rather than spring type) if you are worried by passing waves coming up into the sink.

[blackrose]

A Belfast can be quite deep so a lot depends how much freeboard your boat has. If its a deep boat and low on freeboard the bottom of the sink could come very close to the waterline.

 

Belfast sinks aren't suitable for galleys at the stern of many narrowboats - far too deep to gravity drain. Why anyone would want a stylish sink at the expense of skin fitting close to the waterline beats me, but I've seen people do it so there are obviously many who prefer style over substance. The only things on my boat that aren't gravity drained are the washing machine and the shower. Simple is best and gravity is your friend. I wouldn't want drains from sinks plumbed and pumped into drains of other outlets - extra potential for problems IMO. Brass skin fittings aren't difficult to fit and as long as they're 10" above the waterline then I don't see the problem in having several.

[ditchcrawler]

 

But its the height from water level to the top of the sink which matters in terms safe freeboard, and that is determined by the worktop height rather than the sink depth. You could always fit a non return valve (flap rather than spring type) if you are worried by passing waves coming up into the sink.

Not if it comes out below the water line

[Chalky]

We have an laboratory sink rather than a Belfast sink. They look the same however the laboratory sink is smaller, takes up less space and isn't so deep. Works well in the space we have.

[David Mack]

Not if it comes out below the water line

True!

[michaelR]

Hi, thanks for all the replies which I've found really helpful!

 

Summarising - the Galley should be OK using one outlet skin fitting for a Belfast sink and washing machine plumbed together. I already have a whale Gulps 220 pump for this which I'm going to install.

 

The Bathroom should ideally have two fittings, one for the bath and one for the hand basin - the hand basin should be fine gravity fed - but the bath will use another Whale Gulpa 220 which I've already got.

 

The expansion tank for the hot water system is fine to vent into a separate skin fitting higher up on the side of the boat.

 

Bilge pump is single skin fitting.

 

All the skin fittings should be at least 10 inches above the waterline and it isn't required to have non-return valves.

 

Have I missed anything?

 

Many thanks

 

Michael

[system 4-50]

In case it has not yet been said, always check the outside of anyplace that you drill holes in. You don't want to hit a rubbing strake or other feature.