Comparing Notes on Props:

circusmar

Well-known member
Joined
Apr 11, 2013
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87
Fluid Motion Model
C-24 C
Finally got our Cutwater 28 pulled and on the hards to address our performance.

After a lot of hard work the yard was able to get the prop off our boat. badly keybound!

It's a 19x20 4 blade ACME 304.

We are turning 3660-3680 RPM at WOT. Our observed GPS speed (averaged for current) is around 18kts with full tabs. reducing tabs from maximum reduces speed.
Our Yanmar 6BY2 260 specifies 4000 RPM WOT. We are bottom painted but without significant growth on a standard (non performance) ablative. Transmission is 2.13 reduction. Calculated slip is 38%.

For those that have changed their props where did you wind up?

We are waiting on word from ACME to see what changes to propeller they recommend.
 
What did the boat weigh when they lifted it?
 
circusmar":2oz7t3vn said:
Finally got our Cutwater 28 pulled and on the hards to address our performance.

We are bottom painted but without significant growth on a standard (non performance) ablative.

You will be surprised at how a small amount of growth will have a large effect on engine rpms and speed. Two months in the waters of the LaGuna Madre at Port Isabel attracted enough growth to cut our top speed 4 knots and our WOT 200 rpms. A good scraping of the trim tabs and pressure washing the bottom (we do have a hard non ablative bottom paint) brought our top speed back up to 19-20 and our RPMs back to 4000. Even in the Northwest where the growth is not as aggressive, we pull Willie's Tug at least twice during the summer to clean the bottom.

By the way I notice that Cap Sante Boat Haven now will allow you to use their lift to clean the bottom. Saving a trip by trailer to the car wash.

Good Luck,
 
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