Im almost done with my full restoration project of a 1978 18' hydrodyne from the stringers up. ( Pictures to follow in a couple weeks! ) I was wondering of you who actively use your boats for show skiing, what props you use. The boat I'm building mine after has a four blade 17 pitch that is perfect for low end (4 tier Pyramids) and great for barefoot lines (8 guys). Another guy in the team is lending me a Mercury high five 17 pitch to try. The boat is a 18' with an 06 Merc 225 Optimax. Any suggestions would be great before I drop a ton of money on a prop. Thanks in advance!
I can't tell you the perfect prop, but I can tell you two that I'm not completely sold on. You probably wouldn't go with these any way, since the are BRP, but just in case. 17 pitch viper - too much bow lift 19 pitch rebel - too big of a prop: big clunk going into gear and too much blade area to be efficient.
You won't like the high 5 for bigger stuff or for its lack of reverse thrust. The blades are like little steak knives. My suggestion would be: 15 or 17 Mirage 3 blade 4 Blade Rev4 17 which is probably what the other guy is using. They might make it in a 15 pitch as well, not sure. What it comes down to is having alot of blade area and not too much cup. Lack of cup allows the blades to slip a bit and rev up faster getting the motor into its power band.
I thought the high five was one of the best for low end power..? I have heard the thing about no power in reverse but I don't exactly understand why? I have also heard that the high five might over rev the motor. The four blade 17 has great low end and great top end. It pulls our 4 tier pyramid and it pulls about eight guys at just over forty for barefoot. I really can't wait to get the boat in the water. I'm hopeing this configuration has more low end with the high five and less top end because we are trying to use it in place of our twin rig. We have a twenty foot hydrodyne with twin old 225 evinrudes but the one motor that was rebuilt in the last two years is losing compression.
I used a high five in the past and loved it, and I know Dynebob uses one also on his which has a 250 Merc on the back. I believe he loves his high five too. I pulled many show ski acts with mine and it did very well especially considering it had a single 150 Opti on the back. It is true about reverse though. If you are hitting on it real hard in reverse it cavitates like mad. The extra blades just don't grab that well in reverse. But out of the hole for pulling it has a lot of torque. Give it a try, you might like it. Everyone has their own preferences.
I run a 19 pitch "High Five" on my 250XS and as Greg says I'm really happy with it. ( I recently picked up another 19 for a spare.) I might experiment with a Rev 4 prop in the future, as I've heard good things about them from people in the know. When the Aquanuts were running tripple 225's on their 20 footer they also ran High Fives, so they must also work in the show sking arena. Bob
The 19 high five is widely considered the best barefoot prop ever. Other sizes are not as good. The high five does slip a bit on takeoff. It isn't a big diameter prop. I think for show work you could do better. For normal use, the high five would be hard to beat though. 78hydrodyne, with 8 footers on the back doing 40mph with the current prop, what RPM are you turning. I would have thought you simply needed to drop back in pitch. Maybe even have your current prop reworked by a prop shop, as long as it has enough traction.
Nothing wrong with a high five for personal use boats. For show ski boats, which is what he asked about to pull alot of people, the big 3 blades and some 4 blades are far better. The high five is great for straight line acceleration for small numbers.
Must ski, that was exactly what I was trying to say. The high five doesn't have that much traction. If 78 dyne is pulling 6000rpm on an opti 225 at 40mph with his 8 footers then a shorter prop won't help him. Dyne I'd be interested to hear what RPM you are turning. If your current prop isn't slipping too much, I'd suggest getting it worked back to maybe 2" shorter pitch. I've done a bit of playing with this but not nearly as much as Must ski so do what he says. I found the high five good but it doesn't have nearly as much traction as many of the others.