Boating at higher altitude

[Bocephus]

First, yes I have searched the forum. I'm in the Sacramento area, and my usual lake, Folsom Lake, has an elevation of about 420 feet. The lake is very low, and the entire lake is 5 mph. No bueno.

My wife and I have ventured out to other lakes so we can boat at speed, most at about 1500 foot elevation or less. My question is; I know I will lose performance at altitude, but will it damage the engine or drive unit since it will be 'straining' to make power? For example; Lake Tahoe is about 6400 foot elevation. Besides reduced horsepower, I won't damage the drivetrain will I? Assuming the computer will adjust air/fuel for higher altitudes.

My set up is a 21' Sea Ray 200 Select. Has a 5.0 fuel injected and Bravo III drive with 24 pitch 3 blade props. I don't really want to spend $1500 on new props to occasionally visit lakes at higher altitude. Thanks,

 

[techmitch]

First, yes I have searched the forum. I'm in the Sacramento area, and my usual lake, Folsom Lake, has an elevation of about 420 feet. The lake is very low, and the entire lake is 5 mph. No bueno.

My wife and I have ventured out to other lakes so we can boat at speed, most at about 1500 foot elevation or less. My question is; I know I will lose performance at altitude, but will it damage the engine or drive unit since it will be 'straining' to make power? For example; Lake Tahoe is about 6400 foot elevation. Besides reduced horsepower, I won't damage the drivetrain will I? Assuming the computer will adjust air/fuel for higher altitudes.

My set up is a 21' Sea Ray 200 Select. Has a 5.0 fuel injected and Bravo III drive with 24 pitch 3 blade props. I don't really want to spend $1500 on new props to occasionally visit lakes at higher altitude. Thanks,

1.5 boat bucks is a small price to pay in order to protect and at the same time enjoy your equipment.

 

[kanddr]

You're not really going to hurt anything but you are not going to have much performance without propping down in pitch.

 

[hughespat57]

At 7,000 feet you lose 20% of your power compared to see level. Yes the Map sensor will lean out the fuel to compensate for less oxygen. But it will have a greater tendency to detonate (knock) under load. Which is why you usually reduce the pitch so as to achieve rated RPM. It will feel better re-pitched but it will still be 20% weaker.

The only long term solution for altitude is turbocharger, obviously not worthwhile for occasional visits.

 

[ColoSR]

You aren’t going to hurt anything going up to altitude. I live in colorado and we go from 2500’ to 8000’ depending on which lake we are at. I have never heard of engine damage on an MPI engine, you do have to make some adjustments if you are running a carb.

 

[missnmountains]

When we lived in Colorado, we would take a small ski boat up to Turquoise Lake which is at 10,000 feet. We only changed out the prop to get to the correct WOT RPM. (Smaller Pitch)

Ken

 

[Bocephus]

Thanks, guys. I wanted to be sure it wouldn't damage anything. Same as driving my truck from sea level to Tahoe. It does lose power, but for some reason, it seems boats are much more sensitive to everything. And repairing them is a multiple of repairing your truck or car.

 

[ColoSR]

Ain’t that the truth

 

[techmitch]

Thanks, guys. I wanted to be sure it wouldn't damage anything. Same as driving my truck from sea level to Tahoe. It does lose power, but for some reason, it seems boats are much more sensitive to everything. And repairing them is a multiple of repairing your truck or car.

Think of it this way. How would your truck like it if any time it was driven, it was always going up a steep incline? And yes, even at cruise, this is what your boat is going through. When trying to get on plane, it's like power braking your truck.

 

[Bocephus]

Trucks: Smashed a pothole, ran 500 miles a quart low on oil, filled up on crappy gas from a rural gas station and towed a boat over the Sierras. No problemo.

Boats: Eeeek! I got wet. That'll be $700, please.

 

[ColoSR]

Sadly $700 is a good day.

the irony for me is that my boat will go 50+ mph, on a lake that’s 2 miles across.

 

[Bocephus]

Sadly $700 is a good day.

the irony for me is that my boat will go 50+ mph, on a lake that’s 2 miles across.

When we took ours out for the sea trial, we got her to 51 mph at WOT. Didn't stay there for more than a couple seconds, but she was fast. That was in the San Joaquin river in the Delta.