exhaust and waterlock positioning

[solent clown]

I have all the posh new tube, and the waterlock. I am assuming the waterlock should be as close as possible to the engine so the amount in the pipe aft of the engine does not overwhelm its capacity?
Also the exhaust has to go about 5 feet, then through a bulkhead before continuing the final couple of feet to the outlet. (outlet above waterline) I am planning to put a rubber grommet around the hole in the bulkhead that carries the tube through towards the rear. I was thinking with the waterlock secured well, the engine movement will not greatly affect the tube after the waterlock, but the potential abrading effect is still there I guess.


IMG_20171228_130033 by mark punksteel, on Flickr


IMG_20171228_130059 by mark punksteel, on Flickr

 

[pvb]

I am assuming the waterlock should be as close as possible to the engine so the amount in the pipe aft of the engine does not overwhelm its capacity?

You've got that the wrong way round; you need to ensure that the water in the long pipe from the waterlock to the transom outlet won't overwhelm the capacity of the waterlock. You'd generally work out the likely volume of water in the pipe using 25% of the pipe volume, then doubling it to add a safety margin. If there's going to be more water in the pipe than your chosen waterlock can take, you need to move the waterlock further aft.

There's a lot of useful information and guidance on waterlocks in the Vetus catalogue, which you can view on their website.

Presumably you'll be routing the exhaust pipe upwards before dropping down to the outlet, to introduce a gooseneck?

 

[macd]

Hi SC.
Suggest you check out Vetus' installation instructions. You'll be able to download something relevant from this page: https://www.vetus.com/en/technical-documentation

I think I mentioned in an earlier thread that the Vetus site also has a calculator for minimum waterlock volume. They reckon that never more than 25% of the exhaust volume (from engine to top of gooseneck) is water, but suggest you double that for safety, so the waterlock should be sized to hold 50%. Waterlocks of the type you picture should be installed fore-and-aft; the drum-type can be placed any old way (but upright, obviously).

The waterlock shouldn't be placed too close to the engine. The engine installation instructions should specify the minimum. (Off the top of my head, 300mm from the injection elbow seems to be a fairly typical minimum.)

Or perhaps Mrs SC could crochet something...?

 

[rogerthebodger]

This diagram shows a typical layout.

2 thinks to note

The volume of the water lock only needs to be based on the exhaust pipe volume from the top of the goose neck to the engine outlet.

The goose neck does not have to be right at the transum but the pipe from the bottom of the goose neck must go down hill.

 

[Tranona]

No need to do any calculations - that waterlock is fine for the 1GM. Site it as close to the bottom of the boat as you can. You will need some sort of bracket to attach it using those mounting holes. Make sure it does not tough the hull etc as it will vibrate and make a noise. You won't be able to go too far back from the engine outlet as the hull slopes up. Then run the pipe along the bottom of the hull with a big loop up as high as possible before dropping down to the outlet.

 

[solent clown]

thanks chaps, it is reassuring to have the advice. I can fix the loop to the rudder tube just forward of the stern outlet so that bit is easy. As for fixing the waterlock, I will make a bracket with rubberised mounts we use for fuel pumps and the like. But first I have to get access to the damned area, so it is time to have a chop and build an engine room access panel