prop slippage

**astro1800** · 04-10-2005, 08:11 PM

i am a clever type prop and the numbers i am getting is showing 15% slip. is this a lot of slip? if so how do you decrease slip?

**150aintenuff** · 04-10-2005, 08:49 PM

what kind of hull do you have it on... for a ultra fast 100+ MPH hull 10% may be considered high where as a heavy arsed big 5000 lbs plus hull it may be close... only more information will confirm or deny the 15% slip figure but it does sound about 6% high... 6-10% is considered ideal....

**astro1800** · 04-11-2005, 11:39 AM

the prop is on a weldbuilt 14x48 aluminum boat with a 40 merc with some work done to it. the prop is a hopkins custom clever suppose to be a 22.5 to a 24 pitch on the tips. im turning it 6150 rpms and im running 64mph. when i plug in the numbers to the analyzer it says i have 15 % slip.

**150aintenuff** · 04-11-2005, 11:45 AM

most aluminum hulls average 10-15% slip due to friction from the hull... there are a few minor adjustments you could do but you are fairly close to as good as she gets with aluminum.....

keep in mind a jon boat is designed to have a long flat running surface... not a small section of 10" wide pad... that brings up slip quickly...

**astro1800** · 04-11-2005, 03:03 PM

what small things can be done to decrease slip

**astro1800** · 04-11-2005, 10:31 PM

so maybe a clever style prop is not a good idea for this boat

**150aintenuff** · 04-12-2005, 01:12 PM

the key to getting slip down on the aluminum jon style hulls is getting it to lift slightly... that cleaver will work just add some tip cup for bow lift and loading will make all the diferences...

you want just enough weight in the bow thatr she keeps the transom dry on shut down... and the rest can be moved baack to the rear that will bring your slip down some as well as the jons are known for running very flat... which is adding drag.. also with reletivly flat <6* V's they are HARD to lift the bow as the full surface of the hull has top be lifted to gain anything ...if you can gain 5% reduction in slip i would stop and call it good.... and ber happy that you could even get a jon up to 60+

**Yamaha 225** · 04-15-2005, 04:13 PM

I have found out that if the engine is raised so much that the torpedo is out of the water, the slip increases, but the speed increases too because of the reduction of deplasement of the torpedo on the gearcase.... So how much slip is very difficult to discuss I think! Or what do you think?

;-) Erik

**brotherxb03** · 04-26-2005, 03:25 PM

That 40 must run on nitro to turn a 24 cleaver 6150.

**150aintenuff** · 04-26-2005, 05:05 PM

actually the propis only spining 3075 as that motor has a 2:1 ratio if memory serves..

**astro1800** · 04-27-2005, 08:19 PM

My Gear Ratio Is A 1.83:1 The 24 Pitch Is At The Tips. The Dia. Of The Prop Is Only 11 And 1/2 Inches Its On A 40 Mercury , 14x48 Aluminum Boat And There Is A Lot Of Slip. Me And The Fellow At The Prop Shop Have Agreed That This Prop Will Not Work And He Is Going To Build Me A Hoss Triton Look A Like. Hopefully This Will Give Me More Speed Than The Chopper Did. 65.5mph On A Gps

**Terminal Velocity** · 05-03-2005, 12:21 PM

Who's got the website that you just punch in the info and it will tell you want you want to know, IE speed, slip, gear ratio depending on what you put in the calculator. I had it saved on my website and another computer and lost it.

Thanks,
TV