I am gettng 5400 rpm out of 6000 redlline on a yamaha 100 hp 4s, (2.31 gear ratio) on a 21 foot, heavy, flat bottom, fiberglass skiff. The performance of a borrowed 4 blade prop (13.5 x 15 TP express) is acceptable, actually a huge improvement over the old yammie 3 blade13.25 x 19k. The 4 blade allows me to run my jack plate all the way up v. the three blade venting by raising it just an inch or so. Top speed nearly the same at 30 to 33mph.
I appear to be in the range but how important is it to get toward the top end of rpm range? I am pretty sure going down in pitch one or two degrees might dial it in better? Top speed is not a huge factor within reason...I'm presently running mid to low 20's, 90 percent of the time due to conditions. Running shallow, good holeshot, pulling a tube on occasion, lower planing speed and carrying heavier loads is my main objective
I am considering both turning point and powertech at this stage. When I go to order one should I go 13, 14 or just stay with the 15? Both companies have a exchange program but id like to get it right the first time to avoid boating delays during exchanges.
I'm thinking a 14 to be safe but would like to hear other opinions.
I appear to be in the range but how important is it to get toward the top end of rpm range? I am pretty sure going down in pitch one or two degrees might dial it in better? Top speed is not a huge factor within reason...I'm presently running mid to low 20's, 90 percent of the time due to conditions. Running shallow, good holeshot, pulling a tube on occasion, lower planing speed and carrying heavier loads is my main objective
I am considering both turning point and powertech at this stage. When I go to order one should I go 13, 14 or just stay with the 15? Both companies have a exchange program but id like to get it right the first time to avoid boating delays during exchanges.
I'm thinking a 14 to be safe but would like to hear other opinions.