How to "splice" a smaller diameter bilge hose to a larger one?

Vega1447

Vega1447

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My manual bilge pump (Albin Vega 27) pumps from the bilge in the interior of the keel via a hand pump in the port cockpit locker to an outlet above water level on the transom. Works fine though the locker location for the pump lever isn't great. Approx two inch diameter hose.

I've installed a Rule 12v auto bilge pump with a smaller diameter (approx 1 inch diameter) outlet hose. I was in a hurry and vented it into the aft end of the cockpit. I was never happy with this and would like to vent overboard.

Is there a simple way to "union" the one inch hose into the two inch one as I'd rather not cut another hole in the transom for the one inch outlet hose?

If not, any recommendations for a reliable outlet fitting on the transom? Essentially the same as a through hull fitting for the heads?

Thanks for any advice - I really hate cutting holes in my boat, even above the waterline!
 
Are you talking inside diameter or outside? If the old hose is actually 38mm or 1.5 inch bore then an unequal tee, plus a non return valve fitted below it will allow either pump to use the same outlet.
 
Personally I would not go for a single outlet for the pumps. It is just as easy to fit an outlet of the correct size, as it is to fit a reducing bush & a "Y" junction. I am sure that the new fitting could be placed in an accessible position which would be better. If it can be placed high on the transom one could avoid the valve. I have never shut mine in 18 years. No water, other than an odd dribble, will ever wash back down the pipe in a following wave.
I would NOT recommend a botch job with one pipe inside the other. The clamp cannot be tightened down onto the pipes properly as the inner one will just compress. It needs a proper reducing fitting. They are not expensive in the grand scheme of things. By the time one has fitted 2 jubilee clips to every fitting & bought the reducer, Y junction & pipe, the cost will hardly save anything over a simple transom outlet.
 
Norman_E said:
Are you talking inside diameter or outside? If the old hose is actually 38mm or 1.5 inch bore then an unequal tee, plus a non return valve fitted below it will allow either pump to use the same outlet.
Click to expand...
Thanks. Unequal tee joints are what I seem to need all right.
A specialist item...
Farm supply places maybe - as a reply a minute ago suggested?
 
Norman_E said:
Are you talking inside diameter or outside? If the old hose is actually 38mm or 1.5 inch bore then an unequal tee, plus a non return valve fitted below it will allow either pump to use the same outlet.
Click to expand...
I'd go this route, but you do need two non-return valves
 
Daydream believer said:
Personally I would not go for a single outlet for the pumps. It is just as easy to fit an outlet of the correct size, as it is to fit a reducing bush & a "Y" junction. I am sure that the new fitting could be placed in an accessible position which would be better. If it can be placed high on the transom one could avoid the valve. I have never shut mine in 18 years. No water, other than an odd dribble, will ever wash back down the pipe in a following wave.
I would NOT recommend a botch job with one pipe inside the other. The clamp cannot be tightened down onto the pipes properly as the inner one will just compress. It needs a proper reducing fitting. They are not expensive in the grand scheme of things. By the time one has fitted 2 jubilee clips to every fitting & bought the reducer, Y junction & pipe, the cost will hardly save anything over a simple transom outlet.
Click to expand...
Thanks. I think that persuades me to go for a new transom outlet.
Should I wait till the winter liftout or is it sensible to use a 18v battery hole saw (above the water line of course)?
 
Drill a 1/8 hole from the inside first so that you know where you are going to end up. If it is for any reason wrong you can always stick a No 10 SS screw in the hole & start again. Then, with the hole saw, drill from the outside 1/2 the way through. Then if you have room go inside & drill outwards. That way you get 2 need cut edges to the hole rather than a jagged edge inside.
Just plan the position so that the pipe is not waving about in the middle of a locker preventing you put anything large in there afterwards. ie the outboard, or fuel can etc etc
Or worse still getting anything that you left in there out at a later date :rolleyes:- Like my my mate who put his mast up. Launched his boat then found that he could not get his rudder, with tiller, out from in front of the mast. Mass panic:eek: getting the boat back to the trailer, then back on dry land to start again. :rolleyes:
 
Vega1447 said:
Thanks. I think that persuades me to go for a new transom outlet.
Should I wait till the winter liftout or is it sensible to use a 18v battery hole saw (above the water line of course)?
Click to expand...
Perfectly sensible to use the battery drill and hole saw. If you don’t want to do it from a dinghy why not find a Marina berth to reverse into?
 
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