Universal M-25 Exhaust port underwater? - SailNet Community
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post #1 of 2 Old 07-01-2013 Thread Starter
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Universal M-25 Exhaust port underwater?

Hi All,

We've recently had our inboard installed on our 1986 Catalina 27 Tall rig and are very excited to start using our new (to us) sailboat.

I've noticed that the exhaust port, however, is just at the waterline when we are sitting, and when we are underway it drops to just underneath the water. Other than the fact that it splashes water everywhere, is there any problem with this? Its a pain not being able to look back and visually confirm good water flow and I've never had a boat where the exhaust wasn't at least a couple inches above the water.

I'm not sure what inboard was previously installed. Maybe if my freshwater tank was under the vberth it would make a difference but its under the starboard berth and I don't have a permanent head. Someone suggested adding some ballast under the vberth but I can't think what I would put in there and I'm not sure how that would affect sailing performance.

Any thoughts?


Here is our motor starting on a pallet...

Here is the motor installed... HERE
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post #2 of 2 Old 07-01-2013
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Universal M-25 Exhaust port underwater?

The exhaust port of our M-18 on our 1984 Catalina 27 is setup similarly. Our boat also squats under power. The only downside so far is that the exhaust mixes with the swirling water and leaves some residue on the transom. I've read that large following sees can cause issues by forcing water into the exhaust which can be alleviated by a flap on the exhaust port opening and/or a anti siphon loop
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