Smitty

iTrader: (1)

Wondering what the ideal prop slip % should be for a deep v hull at top speed. According to the slip calculators, I am at 12-14 % at top speed using Hering or BBlades calculators.

I have 28 pitch Maximus props. 1.5 ratio XR drives.

stirling

I found it is different on any given boat ,and propulsion system/or propellor /gear ratio you have .. but one of my boats ran its fastest speeds at 18% slip ,it didn,t bother me at all that the slip was that high ,on every prop I used the slip was lower ,but speed also lower .. without measuring the correct pitch it is difficult to say what slip numbers you run .
If you want to run economic on fuel ,its a different story ,and slip numbers need to come down .

pstorti

iTrader: (2)

what is your top speed? 60 mph? then those numbers are good, 90 mph? the the slip is high.

t500hps

I had a 382 that made 700ft/lbs esch fully dressed. With 32P Bravos I had about 19-21% and ran 87 WOT, 53 at 3,500.......with 15 5/8 28P Maximus I had 11% slip and ran 83 WOT, but 60 at 3,500.

Problem was the boat lost 2 drives within 6-8 months of going to those low slip maximus.

Griff

Most conventional V's will be in the 12-18% range. There really is no "ideal" propslip number across the board. What matters is that your boat peforms its best with the props on it. If you can run 90 with 20% slip, its better than running 85mph with 12% slip.

stirling

Exactly

marylandmark

Few good replies on this recent thread:

http://www.offshoreonly.com/forums/p...prop-slip.html

AJ POWERPLAY

iTrader: (1)

Less slip=less drive life... Go a couple mph slower and save your money on drives!

Smitty

iTrader: (1)

On a cool day I am hitting around 84-85. Warmer day 82-83.

I dinged a prop and they have to be fixed, so i was looking for some others experience so when they fix and retune props, I can tell them what I am looking for.

Engines are at 5500 rpm.

articfriends

iTrader: (1)

I have lowered the slip on my boat before with 5 blade props while testing, it had a slight gain at cruising, killed the top end, tq rolled like a biotch and sheared off a billet prop shaft. My boat goes the fastest and drives/rides the best with about 16-20% prop slip , if your slip is 12-14% you are already pretty low for a boat like yours. People tend to get hung up on prop slip numbers and start thinking IF they could get slip down the speed would increase but other than very small gains that does not neccesarily hold true. Its more like what is better-if my boat goes 95 mph with a 30 pitch 4 blade at 6000 rpm's and 16.5% prop slip or 95mph with a 28 pitch 5 blade at 6000 rpm's and 10.4% prop slip? Normal thinking would make you think that IF you could get that 30 pitch to slip at 10.4% it would run 101.8 mph instead of 95mph, normally the truth is though unless you were to increase the tq/hp its not going to happen , instead it would just pull the motor out of the power band, tq load the drive more and cause a multi tude of other problems. Now, if your boat is poorly set-up, (too high x, pos prop, major flaw) sure you should work on makingb things effiecient. I tried for years to get my slip numbers lower, all it ever did was make things break and boat to handle worse, I quit worrying about it anymore, Smitty