Sterndrive question

[duluthboats]

Ok, here’s a dumb question that proves my amateur status. On a boat that has a sterndrive unit are the water intake, outlet, and exhaust, built into the unit like an outboard? Hey, all my experience is with paddles and outboards. This is an example of what I’m talking about.

http://www.outdrives.com/merc/30litre.html

Gary

[Paul Browne]

Can't be such a dumb question, 'cause already there have been twelve folks view it, and nobody has attempted an answer. I don't know either. I've always avoided stern drives like the plague.

[yipster]

i've been looking at this thread twice but beeing another amateur i not really understood the question
maybe i missed a after the statement?

yipster

[duluthboats]

Thanks for the reply Paul. I have books with illustrations showing exhaust and cooling systems for inboards, I can find nothing for sterndrives.

“I've always avoided stern drives like the plague.”

Why? The only big drawback I can see is the rather large hole in the transom. That is, if the systems are integrated.

Yipster, I added a question mark to correct my error.

Gary

[Paul Browne]

"The only big drawback I can see is the rather large hole in the transom. "

I guess stern drives are OK for fast boats, especially trailer boats, or boats on lifts. But for a boat that's berthed in warm salt water, they're a real hastle. Barnacles grow on them so easily. They snuggle into the rubber bits, and their shells poke holes in them when the stern drive moves. I don't know, seems like everybody who has a stern drive has a maintenance problem.

Somebody who's run one set me straight here if I'm wrong about this. Are they as unreliable as I think?

Paul

[yipster]

i think they are great. sure i bluw an engine once without audio alarm nor temp gauge on seaweed but that, like barnacles can happen to all systems. consider the advantages as well: trimming, thrust vectoring / heeling, you gan even get -and not much more expensive- counter rotating tails and props. the rubbers i'll check this weekend

[duluthboats]

yipster, what I want to know, are all the systems (cooling and exhaust) part of the unit, like an outboard, or are they seperate like an inboard?

Gary

[Willallison]

Yes Gary - all built into the sterndrive unit.
As far as I'm concerned, there is much myth about keeping a sterndrive powered vessel in the water. I owned one for 5 years and had little trouble with it. Granted it was probably a little more expensive to maintain than a shaft driven boat (Servicing usually amounted to about $1000 Oz per year) but the performance benefits are enormous.
I generally slipped the boat twice a year - I'd antifoul the leg every 6 months, and the bottom annually - so it's true that they foul up faster than the bottom. But the shafts etc on my parents boat are just as difficult to keep clean.

[Willallison]

One other thought - some high performance sterndrives have the option of running straight through (the transom) exhausts.

[gonzo]

Mercruiser:
Model 1, MR, Alpha and Alpha Gen II have pumps in the lower unit.
Bravo 1,2 and 3 have a pump at the front of the engine with a pickup at the lower unit

Volvo-Penta
The pump is at the front of the engine or the starboard side with a pulley depending on the year

OMC Cobra
In the back of the upper unit

[duluthboats]

Will and gonzo, thank you both. I took a walk over to my neighbors and looked at his Mercruiser. I just never gave them much thought before. So now I know. They would seem to be a very economical way to go in the 100-200hp range.

Thanks again
Gary