boat speed calculator( by JB)

[phatmanmike]

i did a search and found this from 2 years ago or so... and it seems to work 99% of the time. it was posted by jb...<br /><br />

There is another formula for predicting top speed if ideally propped and trimmed.<br /><br />Prop HP=A<br />Boat gross wght.=B<br />Bottom factor=C: 180 for V bottom, 200 for nearly flat, 225 for Flat.<br /><br />Take the square root of A/B and multiply by C.<br /><br />Example: My Montauk has 70hp, weighs about 1900lb. with max load. 70/1900 =.037. Sq. rt of .037 =.19,<br />Nearly flat bottom factor, 200 X .19 = 38.4mph.<br /><br />GPS WOT reads 38.5mph <br />

you really should put this in the FAQ... i cant count how many people ask "how fast should my boat go?"<br /><br />m ikey<br /><br />p.s that faq needs a good cleaning... broken links and such

 

[sorrydog]

Re: boat speed calculator( by JB)

Lemme try<br /><br />Prop HP - 200<br />Weight - 1500<br />Bottom - nearly flat 200<br /><br />sqrt a/b = .3651<br /><br />.3651 * 200 = 73<br /><br />Within 7 (80mph) - not too bad I guess.

 

[Bob_VT]

Re: boat speed calculator( by JB)

Someone once posted this formula in "EXCEL" format. It works great! <br /><br />I have been hunting for it in the excel format and unable to stumble across it again. <br /><br />Would someone be kind and repost it or the link.<br /><br />Thanks<br /><br />Bob

 

[phatmanmike]

Re: boat speed calculator( by JB)

right here

 

[Bob_VT]

Re: boat speed calculator( by JB)

TY<br /><br />bob

 

[f_inscreenname]

Re: boat speed calculator( by JB)

Here are two I like. http://www.rbbi.com/folders/prop/propcalc.htm <br /> http://www.boatramp.com/prop_applet/PropAnalyzerAppletG.html

 

[sloopy]

Re: boat speed calculator( by JB)

nice only off by 5