Wilks

Have a 38zx Donzi. 12000lb boat.
Tested stock 32p bravo 1 against lab finished 32p bravo 1. Same 15" diameter on both props.
Drives set to 1/8" tow in.
At midrange 3800 the stock prop has 5 mph gps better. 57 stock. 52 lab.
Normal???

Griff

Pretty normal if its just the standard merc lab recipe and not specifically custom labbed for the boat.

bbladesprops

Not unusual to have better cruise with standard Mercury Lab recipe. 5 mph is a little extreme but your hull is where it would happen due to bottom design and common X dimentions.
A adjusted Lab recipe would help.
What are the WOT number comparisons and are you sure nobody adjusted either of the props from stock or standard Merc Lab?

Brett

Wilks

WOT Stock = 4700 and 74 GPS
WOT Lab =4950 and 75 GPS

The stock prop was untouched, no dings. Both set props measured 15" diameter. Lab props was worked by your company.
Both sets of 32's handled equally well and boat rode great.

This is a Daytona edition which has stellings 12" extension boxes, Kevlar hull. I have not measured X to see if it was raised with the stellings boxes. It will blow out props getting on plane if not rolling in slowly which makes me think it has higher X.

bbladesprops

I can look at the recipe in your file and see what adjustments can be made.
Post you name or PM me the info and we can discuss the options after I investigate your recipe.

Brett

Griff

I would try some stock 30's. That WOT of 4700rpms is too low for 575SCi's and even the 4950rpms is on the low side. Best off to run them as close to 5200rpms as you can.

Wilks

It was warm/humid day which took some off of it. I have a set of lab 30's adjusted to 31 the previous boat owner gave me. Made the boat ride like crap. The 32p lab is what is standard from Donzi on the daytona with that power.

Wilks

PM sent

bbladesprops

I received your PM but your name isn't in our system.
Could the propellers have been built for some one else? What are the serial numbers?

Brett

Ran-Dom 32

Sorry to hijack your thread, but I have some ?? re 32 lab slippage as well, I'm trying to reach 5700RPM which is my peak dyno HP , & I'm currently spinning standard merc labbed 32's to 5400 w/1.50 ratio @ 88 , theoretically wouldn't a pair of stock 30's bring the RPM up a couple hundred but be almost same top speed? or are the 30's a more efficient prop? I'm waiting from some cool fall air to run the boat hard again & see if im any closer to 5700 before I commit to propping down