Moderated Discussion Areas
ContinuousWave: Whaler Performance
Mercury's Prop Selector?
|Author||Topic: Mercury's Prop Selector?|
posted 01-30-2002 12:42 PM ET (US)
Ok for all you engineers. I created a spread sheet that uses the "top-speed" formula that is in the reference section SQRT(HP/WT)*hull factor. Then I collected all of the boat weights from a couple of old '80 & '90s catalogs. (In addition I added the weight of fuel, two 170# boaters, and motor weight). All the boats ended up in the 40s with their “max hp” and w/max fuel.
In testing this using members GPS forum reports, members craft tended to be a bit faster then the calc, is was closer if I used a 190 factor, but Merc's calculator always ends up 5 10MPH quicker... I used "offshore fishing" as the boat type.
|BOB KEMMLER JR||
posted 01-30-2002 01:33 PM ET (US)
Did you factor in members stretching the truth a litle?
|BOB KEMMLER JR||
posted 01-30-2002 01:34 PM ET (US)
Little not litle
posted 01-30-2002 03:36 PM ET (US)
I did think of that, I figured if the report said GPS that it would too blatant a lie.
posted 01-30-2002 04:43 PM ET (US)
Yeah, and whats this about 175 pound passengers? Nobody said anything about children.
posted 01-30-2002 08:32 PM ET (US)
So your spreadsheet shows the Merc Prop calculator to be optimistic, too?
posted 01-30-2002 10:09 PM ET (US)
Too bad too, it's a very cool application I suspect the factor is just a bit off...
Here is the complete hull sheet plus a couple of real world examples and a guess for Whale Lure... (hope it fits)
posted 01-31-2002 01:00 AM ET (US)
I tried to get the formatting to work better, but I seem to be fighting with the UBB software. I took the liberty of re-coding the data into an HTML table and including it in the article about propellors which contains the speed prediction formula.
Pete, I need your last name for proper credit and citation. See how the table looks here:
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