Exhaust Systems

[sailorman]

One can but hope!

It looks like Vetus do a thing called an NLPG - an NLP waterlock built into a gooseneck... That saves some money!

that is wot i have

 

[yachtorion]

that is wot i have

Are you happy with it?

 

[Tranona]

One can but hope!

It looks like Vetus do a thing called an NLPG - an NLP waterlock built into a gooseneck... That saves some money!

No. The NLPG is a different animal - a muffler and a gooseneck all in one. Not really necessary. You need the NLP immediately after the engine to collect the water in the system when you switch off. It also acts as a muffler and usually there is no need for an extra muffler. Also no need for the gooseneck as the same effect can be achieved by a loop in the exhaust hose before the outlet, although if space is tight the gooseneck is a good solution. No need for a flap on the outlet as the loop in the pipe stops water from being pushed back. The syphon break is upstream of the exhaust and stops potential syphoning of seawater back into the engine when it stops.

So two different things - water trap to collect water in the exhaust system downstream of the injection point into the exhaust, and anti-syphon to stop raw water from the cooling circuit syphoning into the injection point.

 

[ianabc]

Standpipe vs waterlock

discuss please ......

 

[macd]

No. The NLPG is a different animal - a muffler and a gooseneck all in one. Not really necessary. You need the NLP immediately after the engine to collect the water in the system when you switch off. It also acts as a muffler and usually there is no need for an extra muffler. Also no need for the gooseneck as the same effect can be achieved by a loop in the exhaust hose before the outlet, although if space is tight the gooseneck is a good solution. No need for a flap on the outlet as the loop in the pipe stops water from being pushed back. The syphon break is upstream of the exhaust and stops potential syphoning of seawater back into the engine when it stops.

So two different things - water trap to collect water in the exhaust system downstream of the injection point into the exhaust, and anti-syphon to stop raw water from the cooling circuit syphoning into the injection point.

+1 to all that.
As I mentioned earlier, the OP will need to work out the exhaust volume, top of gooseneck to exhaust elbow. If memory serves, the waterlock needs to be able to hold half of this volume, which gives a 50% safety factor*. (Work it out with Vetus' on-line calculator, or do a bit of simple geometry.) Again, if memory serves, the NLP is available in two sizes, with 5 or 10 litre capacities.

* Because, according to Vetus, in practice never more than 25% of the exhaust volume is occupied by exhaust water.

 

[sailorman]

No. The NLPG is a different animal - a muffler and a gooseneck all in one. Not really necessary. You need the NLP immediately after the engine to collect the water in the system when you switch off. It also acts as a muffler and usually there is no need for an extra muffler. Also no need for the gooseneck as the same effect can be achieved by a loop in the exhaust hose before the outlet, although if space is tight the gooseneck is a good solution. No need for a flap on the outlet as the loop in the pipe stops water from being pushed back. The syphon break is upstream of the exhaust and stops potential syphoning of seawater back into the engine when it stops.

So two different things - water trap to collect water in the exhaust system downstream of the injection point into the exhaust, and anti-syphon to stop raw water from the cooling circuit syphoning into the injection point.

That is my set-up.
my a/s is between the raw water pump & the engine & goes to a cockpit drain so i can monitor what is happening. the previous engine a 4108 didnt have an a/s break