MG, Prop equation

[Carphunter]

MG.............After looking at your reply to my problem, I was wondering, what is the equation for figuring the max speed of a boat. You had the hp, weight, bottom factor, mph, max rpm, and pitch figured pretty precisely. Also, when determining max rpm, should I be using the 13-1/4", 19 pitch 3-blade, or should I use the 12.8", 17 pitch 4-blade. There seems to be a definite difference in the rpm's between the two props. Just in case you forgot, I have a 1981 Dynatrak by Ebbtide, 16.5' tri-hull, with a 1981 Johnson 115hp v4.<br /> Thanks again!!!!!!!

 

[MGuckin]

Re: MG, Prop equation

This is a pic of it, but fix the tach first.<br /> http://www.fishingworks.com/Users/UserFolders/MGuckin/PhotoImages/Max_Speed.jpg

 

[Spidybot]

Re: MG, Prop equation

Carphunter, <br /><br />If only you'd stick to the same thread. Once a topic is started you really should stick to it.<br /><br />A post like this is out of it's original connection and makes no sense to others. We who answered on the first thread can't even follow the discussion this way.<br /><br />Please keep one topic as one thread. <br /><br />Anyway, here's a link about prop stuf ++: http://www.iboats.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=17;t=014920 <br /><br />Thnx.

 

[Carphunter]

Re: MG, Prop equation

Thanks MG,<br /> Sorry UU, but thats why I put MG in the title. On this particular topic, I just really needed his input, thats why the question was directed to MG! But I will remember your advice for the future.