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View Full Version : Finding the correct prop - never ending story??!!



Toffen
06-24-2001, 10:16 AM
Hi!

Summer greetings from Norway.

I added 6,5 inches of setback, new Torque master lower unit and now I have to reconsider my prop choices. Here are the results:

Stock Tempest 25 A45 = top speed 77,8 mph = 6.250 rpms
Blue printed Chopper II 26 inch = top speed 74 mph = 6.200 rpms
DR4 Spinelli 27 = top speed 73 mph = 6.000 rpms
Propshaft height approx. 2,5 inches below the bottom.

Last year with less setback (5,5 inches CMC), best speed was 76 mph with a blue printed Chopper II 26 inch at 6.200 second Raker 24 at 75,5 mph at 6.200 and third Tempest 25 A45 at 74 mph at 6.200. I have not tried the Raker 24 yet.

Crusing speed is 51,5 mph at 4.000 rpms, which is good.

It seems to that the old Tempest has been the prop taking advantage of more setback. Weird that the Chopper II now is slower. The propshaft height is now approx. 2 inches below with all props.

Maybee I should calm down and blue print the Tempest and hope for an additional 1,2 mph = 79 mph. OR do you have any other ideas? What do you think about Mazco HP4 through hub prop? Wery expensive with all these props on the shelf! I may sell some of them cheap...

Specs: phantom 25 with Promax 300. No pad, no notched transom, classic 24 degree V hull. Weight approx. 2.250 lbs.

Cheers, Toffen - Norway

Euroski
06-24-2001, 11:05 AM
My 2 cents... I think anytime you can take a 25 foot boat with 300hp almost 80mph your doing great. But I guess being a boater we all want more. I never did a bottom blue print but from what I have heard you just might touch the 80 mark.

22VelocityProMax300
06-26-2001, 06:36 AM
Toffen,what I noticed last year when I went with the additional 6" setback,(for a new total of 12")I was able to run higher on the plate,especially with the chopper 2.Try bumping it up a bit,keep an eye on the water pressure.You should see a difference.

Toffen
06-28-2001, 03:51 PM
Hi!

How high did you run your DR Spinnelli and Chopper II? I am currently running it 2,25 -2,5 inches below the bottom. I will try to drive it higher pending on waterpressure. However, at the current height I have 30psi +...

Cheers, Toffen

[Edited by Toffen on 06-28-2001 at 03:54 PM]

TUNNEL T
06-28-2001, 11:57 PM
TOFFEN YOU SHOULD CALL MIKE AT SPINNELLI,HE'LL TELL YOU EXACTLY WHERE YOU SHOULD RUN HIS PROP,HE'S PRETTY GOOD ON KNOWING WHAT WORKS ON CERTAIN BOATS. TUNNEL T

Barney
07-07-2001, 02:41 PM
I see many 300's here in Havasu, this is the premeire playground for DCB, Howard as well as a coupled other manufactures that use 300s. On any given day I will see 15-20 boats powered by 300s, 99% of the single engine applications are running Bravos, twins I see mostly with cleavers.

I also see some larger, 25-28 ft, running thier propsshfts very high, some as much as 2-3 inches above bottom.
Keep in mind, that is only a visual estimate.