i have a 31 warlock cat running 1.36ratio 32 bravos on imco boxes,it hops{porposes} at 90-100real bad will changing to 5blades help any,seems to need to carry the nose more

Not necessarily. I was running 17.5 x 31 5 blades on the 40 Skater and porpoised from 50 -70. Went to a 4 blade 18 x 32 and resolved the issue. My cruise speed increased 10 mph.

Every boat is different. When you get into the larger sizes of props each set has their own personality.

Typically if you change the way the boat carries you can modify this behavior. As The Menace showed he went to a larger diameter which changes the lifting characturistics of the props therefore the lift in the boat. Sometimes change is good.

Julie

I believe the change to 4 blades made a greater difference in The Menace's performance rather than the diameter change.

There are some easy options to try. If you would like to discuss them please give us a call at your leisure.

Test propellers and some other quick and easy tests may greatly reduce your porpoising.

Your props may not be the problem. Can you drive through it? Does it get any better over 100MPH?Recently had this problem while dialing in a 40' skater. Changed diameter, pitch, 4 blade & 5 blade, all reacted differently. Check the last 4 feet of the bottom, you may have a rocker. I took the rocker out of the Skater and it runs absolutely perfect.

Chris..

one guy with the same boat had the same problem,went to 5bldes and solved the prob. i really want to stay 4bladed just wondering how to cure it.
yes ive ran it to 113 and it ran smooth but most of the time it hops so bad that im afraid something in the drive is going to break.

and when both drives are at the same on the indicators one throws more rooster tail than the other, i know there some plastic inserts that go in the drives were the trim rams bolt up mine are not there would this let the drive move 1inch uo and down while running.

Yes it may. I think the props should be looked at.

What rotation are you turning?

turning in,

Make sure the bushings are in place and sound.

Have you ever turned them out?