Prop question
Tomkat
Posted 6/13/2019 7:20 PM (#940845)
Subject: Prop question




Posts: 8


Thx in advance Steve. I have some time in my 680 tiller with Yamaha f50 now. With the Solas 3 blade solo I saw 5800 rpm at 32 mph. With 1 extra body 5600 rpm at 30 mph. With 2 extra bodies and a golden retriever 5400 rpm at 27 mph and slow to plane. I was wondering if the 4 blade 11 pitch would give similar rpm and ability to plane at lower rpm? By myself it stayed on plane quite well around 4500 rpm but much under that it would fall off plane. I was also wondering if the 4 blade could over rev if I was by myself. Most times I am using the boat it is with 1 other person and I was happy with planing time and speed but still wonder if it can be improved?
VMS
Posted 6/13/2019 7:32 PM (#940846 - in reply to #940845)
Subject: RE: Prop question





Posts: 3474


Location: Elk River, Minnesota		Hiya!

Being you are at 5800 with just yourself, a switch to a comparable 4 blade would definitely help keep you on plane at midrange speed. In changing though, you’d want to drop 2” in pitch. The drop in pitch is going to do two things for you: first, it will compensate for the loss in rom from the extra blade, and second, it will increase your rpms to 6000 when you are by yourself. Figure 100 rpm loss for the extra blade, and about 300 gained by dropping pitch. Net increase of 200.

You will see a touch of top end loss...maybe a mph or two, but the handling will be better and holeshot will definitely improve across the board.

Steve