90 Degree Heads Outlet - asking for problems?

RobW

RobW

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Hi folks
I am currently replaing my heads seacocks. Got the old ones out without too much bother and now considering what and how to replace them with.

After much contemplantion I am pretty much set on using the Forespar Marelon composite seacocks, such as those found at the following link....
http://www.mackengineering.co.uk/categories/FORESPAR-MARELON-SEACOCKS-&--FITTINGS/PLASTIC-SEACOCKS/

My question is – the old bronze(?) valves had a 45 degree elbow attached to give a straight run from the outlet hose. Forespar only make straight or right angled hose connectors.

How effective would the use of a 90 degree / right angled hose entry point be on a seacock for the toilet waste outlet? Is this a compromise too far - would this be prone to blocking / less than ideal, or is this acceptable?

Has anyone got experience of an installation like this - plastic bronze or otherwise - will it work?

With thanks

Robert
 
pvb said:
Mine has a 90deg bend right next to the outlet seacock. No problems at all.
Click to expand...

Thanks - thats good to know - the alternative is fitting a straight connector, and extending the run of hose, but due to the curve of the hull - this would not be a neat installation.

Rob
 
I don't want to spread doom and gloom on this one but the bend on those seacocks is very tight indeed and I can understand why OP was asking the question.

To those who have had no problem with a 90 degree bend; are yours as tight as this one?

I'm asking because it would sort out a plumbing problem on my boat, but I've always assumed that I would need a swept 90 degree bend rather than a sharp turn.
 
Mine's an ordinary 90deg elbow, something like this...

es49109.jpg
 
Marelon Stuff

The Marelon Stuff has one drawback that is never mentioned in compare with
Bronze fittings.
Is has, to gain enough strength, a huge wall thickness.
The disadvantege is that the inner diameter is much smaller then Bronze fittings.
So you have lesser flow and sooner blockage.
Perhaps not a problem for most people, but keep this in mind.
Herman.
 
HermanD said:
The Marelon Stuff has one drawback that is never mentioned in compare with
Bronze fittings.
Is has, to gain enough strength, a huge wall thickness.
The disadvantege is that the inner diameter is much smaller then Bronze fittings.
So you have lesser flow and sooner blockage.
Herman.
Click to expand...

....from looking at the specs my understanding is that the inner bore is still the same, however you are correct about the wall thickness as the outer diameter of the through hull is greater, and I am going to have ot increase the size of the hole in the hull.

Rob
 
Hmm brings bank memories on my old portofino 31. Sweltering hot summers day in Zeeland me inside the cabin with head under floorboard using a pair of pliers to pluk the toilet paper out of a blocked 90 degree toilet outlet.+ cleaning up afterwards. Now always keep a supply of surgical gloves handy in case of bog trouble :) Sweat dripping in eyes and whole vocabulary of foul language used up in half an hour :). That said if flusher properly each time there was no problem. Still would avoid if at all possible.d
 
VicS said:
Just ensure the crew all know what maximum size of logs are permissible. :D
Click to expand...

without going into too much gory detail, think about the mechanism of a marine toilet - long before anything gets to the skin fitting, it's been through the pump - it either gets mashed up, or blocks the pump!
 
maby said:
without going into too much gory detail, think about the mechanism of a marine toilet - long before anything gets to the skin fitting, it's been through the pump - it either gets mashed up, or blocks the pump!
Click to expand...

......that's a very good point! Whatever has been deposited will have gone through at least two 90 degree bends before entering the outlet pipe!
 
maby said:
without going into too much gory detail, think about the mechanism of a marine toilet - long before anything gets to the skin fitting, it's been through the pump - it either gets mashed up, or blocks the pump!
Click to expand...

Good point. Most properly operating marine heads can push up to six feet (including pipe friction losses). The equivalent length of a 90 degree elbow isn't much (although I don't have my engineering reference manuals to hand). Most boats don't have enough room to manage anything but elbows to skin fittings anyway and have been working just fine for decades. No need to reinvent the wheel.
 
RobW said:
......that's a very good point! Whatever has been deposited will have gone through at least two 90 degree bends before entering the outlet pipe!
Click to expand...

It's actually more than that - the "waste material" will have been forced through the joker valve with several strokes of the pump and will be pretty effectively pulped - by the time it gets to your skin fitting, you are pumping slurry...
 
maby said:
without going into too much gory detail, think about the mechanism of a marine toilet - long before anything gets to the skin fitting, it's been through the pump - it either gets mashed up, or blocks the pump!
Click to expand...

Unfortunately it isn't quite like that. I had to endure several rather unpleasant unblocking exercises where the 90 degree bend on the seacock was made up solid with paper and
@\^*. I re-piped the loo and put a straight hose tail onto the seacock and normal service was resumed.
 
Dazedkipper said:
Unfortunately it isn't quite like that. I had to endure several rather unpleasant unblocking exercises where the 90 degree bend on the seacock was made up solid with paper and
@\^*. I re-piped the loo and put a straight hose tail onto the seacock and normal service was resumed.
Click to expand...

Mmmm, well, there is an educational exercise for the crew as well - wipe, flush, wipe, flush... plenty of water...

soluable loo roll too - get that Thetford stuff...
 
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