Exhaust Sytem Check Valves

[Stevens 47]

I am considering installing a Centek Exhaust Check Valve. This is not to prevent water from entering from following seas. Because of the design of my boat there is no way to get a complete run of exhaust hose to fall to the exit in the transom.

The original design had the hose after the rise from the waterlift just laying on the hull of the boat rising to the exit, about 15 feet laying below the exhaust elbow and below the exit to transom. It would be full of water. Not to mention the possibility of water flooding from a following sea.

I have altered the course of the exhaust to route to starboard to a point 43" above the bottom of the waterlift see the crude drawing, the course would rise up from the waterlift to a bend 45" above the bottom of waterlift, then drop down to the sole of the boat then route up the side then to gradual fall to the exit. A second option is to not rise as high after the exit of the waterlift. I do no that there is possible back pressure with these designs, maybe less with the second option. But there is know way around it unless I go back to the original install would still have a back presure problem as so much of the hose has water lying in it.

In both of these design I am relying on the check valve to prohibit the back flow of water into the waterlift and possibly the engine. When on a starboard tack water would flood back and over the rise in design one.

I would appreciate comments and also experience with Centeks check valves reliability.

Jack

[r.furborough]

Question: Why change what was working is the original design causing problems?

I ask as a badly designed exhaust system can kill an engine quicker than any other engine abuse.

The waterlock on ANY exhaust system should be large enough to contain any water left in the exhaust hose, both before and after the waterlock when the engine is stopped, even if the run to the transom is long.

If you have any doubts about following seas being a problem, then fit a flapper valve on the exit from the exhaust thru-hull or fit a 'gooseneck' just before the thru-hull.

Personally, I would not fit any kind of inline valve in the exhaust system.

[Christian Van H]

Just so you know, I started a previous thread on a similar subject a while back..http://www.cruisersforum.com/forums/...ves-23538.html

[Ziggy]

When the exhaust through-hull is installed in an overhanging surface (e.g., under the transom), a flapper valve won't work. It's not the best design, but some boats are built that way.

[Laidback]

Presume that you submitted your modification to Centek for their input?
See no problem regarding fitting their Check valve, provided you have room for the appropriate model.
Their pdf doc gives some more info :- http://www.mesamarine.com/Centek_CatalogA.pdf

[Stevens 47]

Question: Why change what was working is the original design causing problems?

I ask as a badly designed exhaust system can kill an engine quicker than any other engine abuse.

The waterlock on ANY exhaust system should be large enough to contain any water left in the exhaust hose, both before and after the waterlock when the engine is stopped, even if the run to the transom is long.

If you have any doubts about following seas being a problem, then fit a flapper valve on the exit from the exhaust thru-hull or fit a 'gooseneck' just before the thru-hull.

Personally, I would not fit any kind of inline valve in the exhaust system.

It did work, although I suspect with allot of back pressure. My design should produce less as their is less water in the exhaust hose and I am not wedded to it...can still go back to the original design.

I do have a flapper and am not concerned about following seas.

I hear you on the inline valve that is the reason for seeking others who may have used or installed one in their system. Thanks for the input.

Just so you know, I started a previous thread on a similar subject a while back..http://www.cruisersforum.com/forums/...ves-23538.html

Thanks for that Christian I read the link.

Jack

[Stevens 47]

Presume that you submitted your modification to Centek for their input?
See no problem regarding fitting their Check valve, provided you have room for the appropriate model.
Their pdf doc gives some more info :- http://www.mesamarine.com/Centek_CatalogA.pdf

Thanks for that I will check out the pdf