oMost 28 Skaters with the new 300XS and 15X34 3blade are running 110-111. I am spinning 15x34 4 Blade Dewalds....... 115@6,300 90@5,100. Of course I took my Skater to Shaun Torrente for set up!!

My good friends 28 with 300X's run 121 (GPS) using 15 x34 three blades. Not familar with Dewald props. I would assume the older X motors are faster than the XS simply because they turn more rpm. The Merc four blades for outboards are not a top end prop at least on three cats I tried them on. With 250XS motors that boat should be over 100 mph. Outboards are finicky when it comes to props and setup. Once you nail it leave it alone. I have spent many many hours making little changes to dial in outboard cats. Shaun Torrente is a very knowledable guy on Skater setups.

Steve you get your boat back yet?

I have achieved 115 with Merc 4 blades lab finished props on 300X and 1.65 lowers. Could it be he is giving up a lot of HP with the 250 XS over the 300 XS or X?

I agree the Merc 4 blades do NOT get done. Have run Merc Racing 34 3 blades on my boat back to back against my 34 4 blade dewalds and the mercs were 3mph slower. The 300x's are faster than the XS on the top end unless you work the 300 opti's some in flat water. I just tried a set of dewald 30's 4 blades this weekend. They are awesome. Will post pics soon.
Normally you will loose a couple of hundred RPM running the same pitch when switching to 4 blades. If you were running 31's and went to 32's 4b you might loose 400rpm or so. What brand props are you running and are the labbed?
If so who did the work?

Private message Freerider, He has a 28 with stock 250XS's and it runs over 100. You need to check your engine height and go from there.I would think that 1 and 5/8 up would be a good starting point.

Pics of 30" 4 Blade Dewalds
It is new design that they use on the X Cats overseas.

Nice looking props. What do they cost per set?

Those props really look awesome and perform even better. Are very strong too!!

They are $3500.00 for the set. He has 32's as well as 34's. He will warranty them for 1yr also. No questions on blade failures.
The big thing is the mid range and holeshot. Very minimal slip as the exhaust does not get to the blade surface.
Dewalds number is 610-926-2964. Ask for Dave.
Super nice guy!
FYI this is the guy that owns the F1 Tunnel Boat Props.