[noah]

Having sorted out the problems with the conecting of the engine to the sterndrive on my colvic 21. i now have a few more problems to sort out and hope some of you guys on here can help?.:kissing:

1/ having ending up moving the engine i now have to make up an exhaust for it. There is nothing to work from as the last owners threw the old exhaust away when they took the inboard out in a way this is probly best as i have to start from scratch. the only things to go by that i have is, the exhaust manifold and the remains of the old hole where the exhaust went through the transom. so the first thing is when fitting the new exhaust is there any pit fall to look out for, i.e. dose the exhaust have to run down hill?
secondly what materials can be use to make it up?

2/ the weed trap now fouls the engine so needs to be moved slightly, if it is turned 90 degs then it fouls the hull structure. I have seen the local plummer and he hasn't got any fitting and thinks they are possible gas fittings! is this possible?

 

[scottonjayne]

read your p/m mate,

 

[paul morgan]

Having sorted out the problems with the conecting of the engine to the sterndrive on my colvic 21. i now have a few more problems to sort out and hope some of you guys on here can help?.:kissing:

1/ having ending up moving the engine i now have to make up an exhaust for it. There is nothing to work from as the last owners threw the old exhaust away when they took the inboard out in a way this is probly best as i have to start from scratch. the only things to go by that i have is, the exhaust manifold and the remains of the old hole where the exhaust went through the transom. so the first thing is when fitting the new exhaust is there any pit fall to look out for, i.e. dose the exhaust have to run down hill?
secondly what materials can be use to make it up?

2/ the weed trap now fouls the engine so needs to be moved slightly, if it is turned 90 degs then it fouls the hull structure. I have seen the local plummer and he hasn't got any fitting and thinks they are possible gas fittings! is this possible?

kev yes it needs to slope down fairly sharp within the engine box so any surge of water from the stern cannot ingress into the engine,try contacting vetus they do all kinds of hose including exaust it does not need to be too heat resistant as there is a constant flow of water through it all you would need then is a good stainless trim for the hull as for plumbing remove what you can and take it into a good plumbing supply shop plumb city ect and they should sort it out ok

 

[ChrisP]

Sorry to disagree with you Paul but plumbers merchants are the last place to source sea water proof components.

The problem is that plumber's brass is an alloy of copper and zinc. In sea water the zinc is anodic to the copper and it dissolves, it leaves you with a copper sponge which will fail and under water will result in you boat sinking.

The only safe metals to use under water are naval brass, silicon aluminium bronze, 603 stainless, 316L stainless, monel etc. Even these will need the protection of a sacrificial anode.

There is a device called a water lock which is fitted in the exhaust hose to stop the backflow of sea water into the cylinders, vetus do them as well as the flexible hose to couple the engine / waterlock / exhaust skin fitting. http://www.vetus.nl/en/index.php

Please be careful and don't compromise on any exhaust fittings, cheep hose can contain carbon and this will dissolve the stainless skin fitting as an example. It is a big hole near to the waterline and is attatched to a very expensive lump of metal at the other end by an overgrown garden hose. Any failure of a component will be expensive and unless approved fitting are used will not be covered by your insurance.

 

[paul morgan]

Sorry to disagree with you Paul but plumbers merchants are the last place to source sea water proof components.

The problem is that plumber's brass is an alloy of copper and zinc. In sea water the zinc is anodic to the copper and it dissolves, it leaves you with a copper sponge which will fail and under water will result in you boat sinking.

The only safe metals to use under water are naval brass, silicon aluminium bronze, 603 stainless, 316L stainless, monel etc. Even these will need the protection of a sacrificial anode.

There is a device called a water lock which is fitted in the exhaust hose to stop the backflow of sea water into the cylinders, vetus do them as well as the flexible hose to couple the engine / waterlock / exhaust skin fitting. http://www.vetus.nl/en/index.php

Please be careful and don't compromise on any exhaust fittings, cheep hose can contain carbon and this will dissolve the stainless skin fitting as an example. It is a big hole near to the waterline and is attatched to a very expensive lump of metal at the other end by an overgrown garden hose. Any failure of a component will be expensive and unless approved fitting are used will not be covered by your insurance.

never new that chris thanks for putting me right

 

[Afishionado]

Having sorted out the problems with the conecting of the engine to the sterndrive on my colvic 21. i now have a few more problems to sort out and hope some of you guys on here can help?.:kissing:

1/ having ending up moving the engine i now have to make up an exhaust for it. There is nothing to work from as the last owners threw the old exhaust away when they took the inboard out in a way this is probly best as i have to start from scratch. the only things to go by that i have is, the exhaust manifold and the remains of the old hole where the exhaust went through the transom. so the first thing is when fitting the new exhaust is there any pit fall to look out for, i.e. dose the exhaust have to run down hill?
secondly what materials can be use to make it up?

2/ the weed trap now fouls the engine so needs to be moved slightly, if it is turned 90 degs then it fouls the hull structure. I have seen the local plummer and he hasn't got any fitting and thinks they are possible gas fittings! is this possible?

When I read your post I immediately knew the book to recommend to you. But I could not for the life of me remember it's name:g:
Then suddenly out of the blue it has just popped into my mind........:clap2:
It was written back in the 60's by in the days when there were a load more DIY boat owners but it is exactly what you need as it explains how to make up your own exhaust systems out of stock iron water pipe or how to fabricate one from sheet steel. It is a very definite 'hands on' book with little reliance on shop bought gadgets.
John Watney Marine engines and Conversions. I think it is still available from Amazon.

Afishionado

 

[alana]

one small tip.......allways use 2 hose clips on each joint