prop selection

[Blue Streaker]

87 115hp yamaha on a 16 ft searay

ss prop 13 x21 my wot was 4800
just bought aluminum 13 x 19

what do you think my wot will be ?and will I slow down or
maybe a little faster
motor should run between 4500 and 5500
for wot does that mean I should be at 5500 ?

 

[Barnacle_Bill]

Re: prop selection

You should see an increase of 3-400 rpm. this is assuming both props are either cupped or un-cupped. Here is a good article about props. http://boatfix.com/how/props.html