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View Full Version : V drive vs I/O



Dregsz
06-16-2007, 01:11 AM
The thing I'm wondering is how does a V drive compare to a sterndrive, and what is a 74' doing as a V drive???
How much slower is a V drive then a Stern drive?
Then there is no drive trim...

Any Opinions?

zelatore
06-16-2007, 09:39 AM
I'm shocked to see nobody has responded yet.

Well, since we're both on the "right" coast :wink: I'll take a brief stab at it.

Here's the catch - my experince is in larger, slower boats; I've never run a performance boat with a V-drive, so take this with a grain (tablespoon?) of salt.

A sterndrive is typically faster due to the ability to match trim to running angle. I'm afraid I can't put a number on it, but maybe 10-15%. There's a similar increase in economy for the same reason. It's also going to be easier to trailer since you can tilt the drive up and don't have to build a cut-out in the center of the trailer's frame. You can also build the trailer lower to the ground to make launch/retrieval easier.

Sterndrives are certainly easier to control at docking speeds since you have vectored thrust. There's a reason they invented bow thrusters - it's called single screw inboards!

Sterndrives are higher maintenence than inboards. You've got a much more complicated system and it's hanging out there in the water. Looking at your location, I have to ask - are you going to run that thing in salt? I don't know how many boats I've seen with destroyed drives because the owners left them in salt water. All it takes is a little forgetfullness about keeping up with zincs, or a small scratch for the corrosion to get a foothold and that drive will seem to rot before your very eyes. If you keep it on a lift or trailer, it's not such a big deal although you'll still want to flush it after being in salt.

V-drives are practially bullet proof. They're mechanically simple and have been around forever. How tough are they? I just commisioned a 65' Marquis with twin 1500 hp MTU's pushing nearly 100K lbs over 32 knots. Try that with a sterndrive! (not that you'd want to)

There's a lot less 'stuff' under the boat to worry about if you keep her in the water - again, espeicially salt. Instead of a transom assembly, gimble ring, outdrive, prop(s), etc, you've got a shaft, strut, prop, and rudder. Each is simple and realitivly inexpensive. You've also got an easier route to go should you have to look for a leak. Just check the packings on the rudder and shaft. And with modern drippless packings having 2000 hr warranties, you shouldn't have to worry about dry bilges anymore.

The V-drive will take up more space inside the boat since you have to add the transmission and v-drive unit on the inside where that mechanical action is done outside the boat with a stern drive.

Lastly, the V-drive might be 'cooler'. Everybody has a sterndrive. They're the most common thing out there in small boats. The V-drive has a bit more of the unusual going for it. Plus all the wake board dudes (btw - does anybody actually ski anymore or am I just getting old?) are migrating their tow boats to V-drives so to that crowd it's the 'latest and greatest' thing.

All that said, for a small trailer boat like a Classic or similar, I'd go with the sterndrive. For a larger boat that stays in the water, inboard every time!
(yes, I acutally walk that walk...I've got a 22 classic with a Bravo I and a 32 Carver with twin 454/V-drives)

Again, there are certainly people on the board with infinitly more experience than I running performance V-drives. I'm more accustom to working on larger cruisers and yachts, but in the past we've sometimes offered the same hulls with boat systems so that's what I'm drawing on for this little rant.

MOP
06-16-2007, 12:10 PM
All of the above is good reading, my add on is the V drive will last a very long time with little to no maintenance. Yes you will be a bit slower but you will always be on the right end of the tow rope!

Phil