Re: 03 daytona with 525
 

Time To Burn....I don't think your formula is correct based on my math:

5300RPM*28P*1.5*.00094697*.10=21.07MPH? I sure hope not!

Perhaps I am missing a decimal point in that calc. somewhere or not using the correct number?

Re: 03 daytona with 525
 

You're missing a decimal, it should be 210.7 mph...... :D

Re: 03 daytona with 525
 

If my theoretical is 210.7MPH then that means that my slip is about 40%? ;) :drink:

Re: 03 daytona with 525
 

5300 X 28 P X .67 (1.5 Gear Ratio) X .00094697 X .90 (10% slip) = 84.739 MPH

You must figure the gear ratio into an decimal number and also for slip take % of 100.

Hope this help!

Re: 03 daytona with 525
 

The caculation basically determines the props or boat distances of travel in one rotation... so when you times these number together the explaination is to prove that the slip is extra critical.
For example:

At
5% (.95) you see 89 mph!!!!!!!!!!!!!!!!!!!!!!!!! (which is hard to get).
15% slip (.85) you see 80 mph! (Do not get discouraged- this is a great percentage for a single engine Cat.) The SLIP IS BETTER ON CATS, than V-bottom.

OF COURSE there are many factors to determine a boat speed... this only gives you a hypothetical rate or explanation of HOW FAST THE BOAT CAN GO... I look at slip as the drivers comfort and ability to drive a boat fast SAFELY. Have fun with these numbers.

Re: 03 daytona with 525
 

Great dialog. My slip percentage on a V-Bottom according to the given mathematical formulas is 13%. That is calculating my actual top speed using a hand held GPS. Here are the specs: 23 pitch, 5150 RPM, 1.5 gear ratio, 74.7 theoretical speed, 65mph actual speed. That is 13% slip on a semi-performance V-bottom. How does that compare to the Eliminator Daytonas as far as slip percentages? Looking at cats, not yet sold on the design.

Re: 03 daytona with 525
 

Slip is somewhat high on a cat until it starts packing air, which will happen at around 70-75 mph. 8-10% slippage is good on a cat.

Re: 03 daytona with 525
 

Yes... The props efficieny is extremely proficient once the boat is on plan.

ALL VBottom have a higher SLIP ratio than CATS, but 13% is excellent for a Vbottom.

Re: 03 daytona with 525
 

My 25 daytona runs around 12 percent slip with a bravo and 13 percent with a black hawk at 5200 but runs 6 % at 4000 and 26% at 4000 respectively,
9% at 3000 and 34% at 3000.
Speeds for each drive at 3000 rpm = bravo 50, bh 40 mph
4000 bravo= 70, bh = 60 mph
5200 bravo = 83, bh = 91
As you can see, once the hull starts packin air, the slip numbers fall really fast for the bh drive as the boat rocks back over the step in the hull. The bravo can be forced to this ride attitude with positive trim so the slip stays low no matter what speed whereas the bh needs forward speed to pack air and lift the bow to get the slip down. At 2500 rpm. the bh drive has nearly 45 % slip. Really only a top speed drive setup.

Re: 03 daytona with 525
 

It would appear that the basic combo for a 25 or 26 daytona is a 1.50 gear set with a 28 prop or a 1.36 gear set with a 26 prop. Seems to be the standard combos I have seen out there. 1.50 may be a little quicker getting to the top but the 136 has better cruise and top end speeds.

1.36:1 spinning 26" at 5200 at 10% slip =86.29 mph
1.50:1 spinning 28" at 5200 at 10% slip =84.03mph.