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Salt water vs Fresh water

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Old 03-04-2005, 08:47 AM
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Default Re: Salt water vs Fresh water

Quote:
Originally Posted by Sydwayz
Mine was a tad faster in salt, but I could definately feel the more bouancy of the SW in the handling of both of my boats.
So, can we assume that the extra bouyancy cause outdrives to blow up?
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Old 03-04-2005, 09:44 AM
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Default Re: Salt water vs Fresh water

I have run in the Gulf(very salty) and also in Lake Tarpon(fresh) on the same day and noticed NO difference.

Sure, saltwater is more buoyant because it's more dense, but at the same time the hydrodynamic drag coefficient is also more due to this increased density.

Most of the claims of incresed speed are due to altitude. Saltwater is always at sea level and most lakes are above.

Atmospheric pressure decreases roughly 0.5psi for every 1000' of elevation. See here:
http://www.offshoreonly.com/forums/s...ad.php?t=58617
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Old 03-04-2005, 09:55 AM
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Default Re: Salt water vs Fresh water

My claim of 2 mph is not scientific at all but max I have hit on GPS on our lake is 80.2 that was very light...fumes... and only 2 guys, altitude is about 100ft and again on the same gps in Florida is 82.1 with about 1/3 tank of fuel and four guys. I have blower engines so altitude is not an issue. And the more humid of the two situations was probably Florida. If anything the 80 on the Lake was harder to hit than the number in Florida, on the lake I had waited till the boat was on fumes and ran it just for that purpose. In Florida we were just trying to keep up with Jim Lee in his Skater 47... futile effort obviously!

Might of been the chop was different and all but that is the numbers I have experienced.
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Old 03-04-2005, 01:32 PM
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Default Re: Salt water vs Fresh water

Quote:
Originally Posted by craig223
So, can we assume that the extra bouyancy cause outdrives to blow up?

Hmm don't know for sure on that one. I only got 3 miles in the salt before it happened that day, but it sure was fun.

Actually, I was referring to being out on the Choptank River, right off the salty Chesapeake Bay. I went out and played around a bit, whipping some turns, and such, and I could feel the handling difference.

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Old 03-04-2005, 01:40 PM
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Default Re: Salt water vs Fresh water

I've seen the difference first hand.

My old boat would cruise at 52 mph at 3600 in salt water. When I would go up the Hudson River and get past Haverstraw into brackish water I would loose 2 mph in cruise speed. This was NOT due to currents because no matter what direction I would go in the MPH was 2 MPH less, the boat also felt like it was dragging an anchor.
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Old 03-04-2005, 02:12 PM
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Default Re: Salt water vs Fresh water

Quote:
Originally Posted by Sydwayz
Mine was a tad faster in salt, but I could definately feel the more bouancy of the SW in the handling of both of my boats.
The empty corona bottles rolling around on the floor had nothing to do with the extra weight or speed did they?
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Old 03-04-2005, 02:38 PM
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Default Re: Salt water vs Fresh water

The only difference I noticed was the boat came on plane faster... probably due to the denser salt water...
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Old 03-04-2005, 10:29 PM
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Default Re: Salt water vs Fresh water

I would think there would be less of a difference in a stepped bottom hull than a straight bottom. I posted my fastest speed in our T/S Gun on Lake Havasu which was 83.6. I saw a little over 82 in the salt. Not implying that salt is slower, but I never seemed to be able to post a bigger number on it.
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