I read a book last winter titled "The Blockade Runners of the Confederacy". There was a chapter about the Rebels inventing underwater exhaust on the steam engines to escape detection from the Union blockade ships. They had valves to switch to shift from the smokestack to underwater(possibly the first silent choice) but only used it when necessary because of the back pressure on the engine. Just a little history 101 tonight.

just a question ,how about sitting in open water can waves and water get pushed up into cyls thru open exhaust valves,otherwise sounds cool

No more chance than any other exhaust that exits the drive or below the water line like almost all pleasure sterndrives.

We have on the 50 V with 6's. On the Bravo we use transom mounted turn downs to put it under the water at idle only.

Terry,

What power was in the 50" V-Bottom? Did you notice (Anything) Different from the cat to the V-Bottom?

Also I for one like the sound of two into one exhaust very unique very different. But if memory servers me seems the biggest reason people have gotten away from that is the ( Y )
pipe cracking at the welds with heat expansion. I don't see that as a problem with your rubber connectors.

But in the past year or two the 41' Apache WarHawk was restored and he had two into one exhaust and was hoping to go with it again. Can't remember the details, but if memory serves's me ( I Think ) Teague wouldn't warranty the engines in the configuration. Or felt the would make the proper power, they are Teauge 900's.................

So is Mecury concerened with that?
Also are you increasing you exit pipe, like going from two 4" pipes into on 5" or 6" pipe to keep the flow?

Thanks
Cougarman

The 50 V had trip 850's
The collector pipe is 6" i.d.
Mercury loves the system and is pushing for everyone to do something like this.

Sounds thought out !!

Thanks
Cougarman

It would be great to have this available for the aftermarket, but I suppose that it's a custom item or for an OEM who can order multiple sets.

Do you think the NorTech cat setup might work on other cats? I'd like to have it.
Due

I have custom turndowns on my 50v with triple 6's, had to custom make them so they would fit between drives, etc, work awesome, would work on other cats if you have enough room to drop exhaust behind motor thru transom, the nortech cats have a ton of room in the engine compartment. I'm sure cmi will build you a custom set of tailpipes for the under water exhaust, but open your wallet.

wiggler,
Not so sure CMI is anymore expensive than others on downturns. What are you getting for a pair of your custom downturns? CMI maybe cheaper than you think.

Rick