speedmaster prop diameter?
 

I'm helping a friend gather info before he purchases the wrong props after his last ones were stolen.
Specs: 31 ft Awesome cat (Linder Design)
supercharged 540's 900hp
B&M trans
speedmaster IV on boxes(big shaft)
X at 2.5 inches above bottom
all props have been 4 blades
17.5 diam 30's spun around 6400rpm
17 diam 32's spin 5600
speed is 115 on gps speedo

Will a 16 inch diameter hurt anything?
What are some advantages/disadvantages to different diameter props?

The boat seems to handle better with the 16.5 and 17 diameter wheels.
We realize the combo is a little different but any input would be appreciated.

Re: speedmaster prop diameter?
 

Diameter on the Speedmasters is important. It's something that has to be worked with to get it just right.

The goal is to run as small a diameter prop as possible. The question is what's the smallest diameter. There are many factors that come into play when deciding on diameter. Too many to get into detail here.

Going to a 16 inch diameter could be disastrous from a performance perspective, but without knowing more details about the boat it wouldnn't be possible to answer the question.

If you have questions give us a call. At least you have the large shaft props which are easier to find.