Help with PSS gland & anti-siphon plumbing

[Babylon]

New Beta 25 engine finally in, also new PSS gland. Two tasks I need technical help with please. (Old engine was direct cooled, trad gland and no anti-siphon, so I have no experience of this.)

Problem 1 is how to feed off the engine cooling plumbing to provide water to the upstanding nipple on the PSS gland. From where exactly do I take this feed? Do I take it off upstream of the heat-exchanger or immediately downstream just before it joins the exhaust gasses in the elbow? How exactly does one T-off a metal pipe fixed onto the engine, and using what sort of hose and fittings?

Problem 2 is how to install an anti-siphon loop into the system. I understand this comes off around the exhaust elbow, but where exactly, and again using what kit?

We relaunch on Saturday and I don't want to sink the boat by fouling this up. I can't easily find photos of other similar installations to help me.

TIA

Babylon

 

[vyv_cox]

New Beta 25 engine finally in, also new PSS gland. Two tasks I need technical help with please. (Old engine was direct cooled, trad gland and no anti-siphon, so I have no experience of this.)

Problem 1 is how to feed off the engine cooling plumbing to provide water to the upstanding nipple on the PSS gland. From where exactly do I take this feed? Do I take it off upstream of the heat-exchanger or immediately downstream just before it joins the exhaust gasses in the elbow? How exactly does one T-off a metal pipe fixed onto the engine, and using what sort of hose and fittings?

You will see from the instructions provided with the seal that you only need a forced supply if you have a high-powered mobo. Your Beta 25 probably doesn't fall into this category. All you need to do is run a length of hose from the nipple to a point above any conceivable water level. Mine runs up to the top of the engine compartment, where it is about a foot above the water level.

 

[rob2]

The two issues could be linked (if I've understood correctly). Most engines have a rubber hose from the heat exchanger to the injection elbow - this is the one which has the anti-syphon valve fitted in it. The hose is taken to a point which is constantly above the waterline, even when sailing well heeled, and the syphon break is fitted there, then the hose runs down to the injection elbow. There are two types of valve used, one type has a rubber flap valve so that in normal operation very little water leaks out - the only down side is that the valve requires cleaning from time to time or it can clog with salt deposits. The second type has no valve but a small capillary tube leads from it and there is a constant flow if all is well. The flow can be directed down through a cockpit drain so you can keep an eye on it to confirm that cooling water is flowing.

http://www.force4.co.uk/1123/Vetus-Airvent-Anti-Syphon-Device--Type-H.html
http://www.force4.co.uk/1122/Vetus-Airvent-Anti-Syphon-Device--Type-V.html

You could tap of the hose leading to the syphon break to feed the PSS seal - after all there will be water flowing if the engine is running. But as Vyv says, you're hardly likely to exceed 12 knots under power, so you only need to run a bleed pipe off the nipple to stop any leakage running ito the engine bay.

P.S. If the exhaust elbow is above the waterline, anti-syphon loops become optional - but a swan neck arrangement in the exhaust is needed to stop the exhaust hose filling with water! The Vetus site does quite a nice explanation of all these things.
http://viewer.zmags.com/publication/dde28f6a#/dde28f6a/64

Rob.

 

[alahol2]

There's a picture of a syphon break on a Beta 13.5 on this page... http://www.troppo.co.uk/engine.htm
If yours is a similar layout you can turn the exit hose from the heat exchanger through 180 deg to point 'up' then join a new bit of hose to raise the syphon break as high as possible. The break in the photo is the Vetus without a valve, the 'piddle pipe' hadn't yet been fitted.

 

[Babylon]

Viv, Rob, Tightwad

Thanks for the feedback: suddenly the whole job has been demystified and enormously simplified!

Going with Viv's advice about just having an open breather above the waterline.

Tightwad, nice simple solution to connect directly to the rotated 90 degree bend in the existing hose.

Rob, I've got a Vetus water-trap already fitted between the exhaust muffler and the transom outlet. I've also already picked up a cheap plastic anti-siphon loop from Force Four (one with a simple rubber valve), rather than shell out nearly four times the money for a Vetus one - is this a false economy or need I not really worry? The loop will be very accessible right in the front of the engine bay, so can be inspected/cleaned regularly.

Cheers

Babs

 

[macd]

I did exactly what alahol2 suggests with my Beta 28. Dead simple and works a treat. Also have a PSS seal, plumbed just like Vyv's (except into a cockpit locker). Absolutely no need for a forced feed.

PS (or should that be PSS?): a hose clip tightened onto the prop shaft immediately forwards of the PSS steel rotor prevents any possiility of it moving forward (say if you remove the shaft for some reason, then forget to tighten the grub screws, which only an idiot would do, obviously. This idiot found that out the wet way.)

 

[Tranona]

Rob, I've got a Vetus water-trap already fitted between the exhaust muffler and the transom outlet. Cheers

Babs

Sounds like you have this the wrong way round. The water trap comes immediately (well at least 30cm) after the exhaust outlet from the engine, then a muffler (usually a waste of time) in the run between the trap and the swan neck before the transom outlet. See the schematics in the Vetus catalogue.

 

[Babylon]

Sounds like you have this the wrong way round. The water trap comes immediately (well at least 30cm) after the exhaust outlet from the engine, then a muffler (usually a waste of time) in the run between the trap and the swan neck before the transom outlet. See the schematics in the Vetus catalogue.

You're right. I made a mistake: I meant to say I had a Vetus gooseneck at the transom and a muffler midway between the engine and this. I don't have a water-trap.

As it happens, there isn't a lot of room for the gooseneck to be mounted fully vertically inside the transom, so its mounted at about a 45 degree angle, which isn't optimal but is better than nothing.

OK, the muffler isn't great (just a heavy rubber cylinder about 150-175mm diameter with s/steel caps at each end) but its also better than nothing.

So, the question is: do I really need a water-trap as well?

 

[VicS]

OK, the muffler isn't great (just a heavy rubber cylinder about 150-175mm diameter with s/steel caps at each end) but its also better than nothing.

So, the question is: do I really need a water-trap as well?

The watertap is the important bit.

It is there to catch and safely hold all the water that is in the exhaust system when the engine is shut down and it should have sufficient capacity to do that.

The muffler is just a silencer. Taking it out and replacing it with a straight piece of rubber hose will probably make no discernible difference to the exhaust noise level.

 

[BabaYaga]

I don't have a water-trap.

OK, the muffler isn't great (just a heavy rubber cylinder about 150-175mm diameter with s/steel caps at each end) but its also better than nothing.

So, the question is: do I really need a water-trap as well?

The rubber cylinder you have might well be a water trap. Sounds like a description of the Volvo Penta type. If it looks like the one pictured in this link

http://www.drevia.se/cgi-bin/db.pl?...l=db_lista.html&template_file=db_artikel.html

it definitely is.

 

[Babylon]

That's the one!

The rubber cylinder you have might well be a water trap. Sounds like a description of the Volvo Penta type. If it looks like the one pictured in this link

http://www.drevia.se/cgi-bin/db.pl?...l=db_lista.html&template_file=db_artikel.html

it definitely is.

Fantastico! That's exactly it. Haha! I've got a water-trap already! I've got a swan-neck, and I'm reliably informed that I don't need a muffler! This forum comes up trumps again!

[dances around the room with his netbook]

 

[macd]

...and I'm reliably informed that I don't need a muffler! [dances around the room with his netbook]

Very reliably informed. Many, possibly most, yachts don't have a...can we call it a silencer since the Atlantic is to our west? The water trap itself works as a pretty effective silencer.

Dance on!

 

[Tranona]

Fantastico! That's exactly it. Haha! I've got a water-trap already! I've got a swan-neck, and I'm reliably informed that I don't need a muffler! This forum comes up trumps again!

[dances around the room with his netbook]

Just to calm you down a bit - the weak point of the Volvo type water trap is the welds on the end plates. Worth checking there are no signs of corrosion or leaks as I guess it will be difficult to get at once eveything is in place. BTW I solved the problem of limited space for the gooseneck by taking a big loop of exhaust hose under the aft deck and a 90 degree fitting through the transom.

 

[doug748]

.......

Rob, I've got a Vetus water-trap already fitted between the exhaust muffler and the transom outlet. I've also already picked up a cheap plastic anti-siphon loop from Force Four (one with a simple rubber valve), rather than shell out nearly four times the money for a Vetus one - is this a false economy or......
Cheers
Babs

I have one of the cheap jobs. It tends to pass water....no problem as it is better than it sticking. Put a tube onto the outlet and you can blow/suck down it now and again to check it is working. I sort out it's incontinence by putting a bottle on the end.
It will come to all of us, I guess.

 

[BabaYaga]

Also be aware that if your silencer/water trap indeed is a Volvo Penta part, it will probably be made to accept their 45 mm (or 57 mm) ID exhaust hose and not the 50 mm ID used on the Beta.

 

[Babylon]

Also be aware that if your silencer/water trap indeed is a Volvo Penta part, it will probably be made to accept their 45 mm (or 57 mm) ID exhaust hose and not the 50 mm ID used on the Beta.

Good point. I have already had the forward end adapted from 45 to 50mm OD to accept the Beta's exhaust hose, and am led to believe that the slightly narrower continuation from the water-trap to the gooseneck won't effect the exhaust gasses etc.

 

[Tranona]

Pipe diameters don't seem to be that critical. My Nanni uses 40mm where Beta with the same base engine is 50mm. The old Yanmar 1GM was 45 so I put an adaptor in the water trap inlet. Worked fine.

 

[Babylon]

Just to calm you down a bit - the weak point of the Volvo type water trap is the welds on the end plates. Worth checking there are no signs of corrosion or leaks as I guess it will be difficult to get at once eveything is in place.

I can just about get to it by humping the engine. Its only a couple of years old so in good shape. When it does go, I invest in a Vetus water-trap.

BTW I solved the problem of limited space for the gooseneck by taking a big loop of exhaust hose under the aft deck and a 90 degree fitting through the transom.

That's just what I used to have - until a certain disgraced Bukh engineer in Southampton decided to add the Vetus gooseneck and charge me for it WITHOUT ASKING ME FIRST. I'm going to borrow a small boy to go into the cockpit side locker and see if we can get the thing more vertical.

Thanks again for all the feedback.