What is the best exhaust location on a CCA type sailboat?

[bntii]

Hello all,

Long last I am nearing launch after a refit of my old Rhodes.
I have re-powered with a 37hp/3000 rpm diesel and am about to do the exhaust run.
A couple of questions:

1) Centex has me in a 10" water lift can and recommends 2.5" hose- this seems awfully large...... Does this diameter sound about right to you guys?

2)The old exhaust was run out under to transom about 1/2 way up from water line. I am about to place a new fitting (hull glassed in over old), and am wondering if the old location is ideal or if I should go for a side exhaust. I have heard of the "North Sea" system (run side to side) or just off one side..
I have never driven a side exhaust boat and would like to know the pros and cons. With such long over hangs- the boat is quiet with the exhaust run aft. I intend to use a inline exhaust check valve from Centex as well.

3) I am hearing that the cooling water in engine has a higher volume than is needed by the lift can, and that some of the water should be diverted overboard before the can. Is this true or a good practice?

Thanks much all

http://home.att.net/~mt.rainier.boatworks/Image003.jpg

[Landlubber]

bntii,

The split exhaust, using a water separator as well as water lift muffler is an excellent idea, the end result is an almost silent exhaust.

The system is used extensively now in genset operation.

I would stick with the centreline transom system also, decreases the worry about heeled hulls in backflow etc etc.

[Roly]

"The split exhaust, using a water separator as well as water lift muffler"
Got a diag. of that LL?
Thanks.

[Landlubber]

Roly,

The unit I was referring to as the water separator is the same as the "Gen-Sep" shown on this web site.

http://www.centekindustries.com/product_descriptions.html

The three holes in the bottom are for wet exhaust inlet (outside), water out (middle) and exhaust gasses out. All they are inside is a simple pair of barriers . The water flows out one and the gases go out the outer.

We install these suckers on the gensets, but they could be used on small engines just the same.

In use the water discharges just slightly below the waterline, just above the chine, that way you can still see the water flow is OK, You see a few bubbles in the water flow to distinguish it from simply water. The exhaust gasses are then passed out the back of the boat, above waterline.

In use they are so quiet, that some people do not believe you are really running the genset, standing on the wharf, it is almost inaudible.

The standard wet lift muffler goes in the normal place, wet elbow exhaust feeding into the muffler, the exhaust of the muffler is then fed into the water separator section.

Hope you can understand this.

[Roly]

Thanks LL. I only had the std wet muffler and it fell apart when I was taking it out! I have a yanmar 3gm30 (30hp) I have rebuilt the transom to walk thru
and scoop for crew weight, down wind, so it presents some challenges for exhaust exit. I like to keep things minimalistic.

Unrelated, but
I had a two "good omens" (not that I'm particularly spiritual) with my boat.There was the distintegrating exhaust (delaminated) and when we were testing the leak in slam area with backstay tension (docked) the back stay snapped! (The rig had recently been serrviced.) Can't be too vigilant.