Z1 - 343hp vs. 303hp & prop pitch- any input??

[Dave S]

A friend is looking at a few Z1's to purchase one. One brand new 11' has a 303 in it and the others all 343. I have a 343 in mine and it does great. I am sure with the 303 he could reprop with a different pitch if the hole shot seems slow and then he may only lose top end speed, right? I have been boating a long time but still am learning about pitch numbers on inboard props (My first inboard). Any insight or opinions would be great.

Can someone also enlighten me on prop pitch numbers...

Ex. I am pretty sure my prop is a 1235 and I belive the dealer told me the 303hp boat has a 537 prop. I know on and outboard, I/O for example a 19 pitch prop means it takes 19 inches of travel for one revolution. How does pitch work with inboard props. ie difference between 1235 & 537.

Thanks for the help!

[rensink]

1235 is bigger pitch and bigger diameter thus creating more hole shot but also removes the top speed however increases rpm's on the top end which has to be watched if you were to run the boat WOT for an extended period of time.

[Dave S]

Coincidentally, I just dropped off my prop at the shop to get a few blades corrected and the guy explained it to me. The 537 (which I do have) is stamped on the hub area where the shaft would go through it. He said the 537 part number is just Acme number. The diameter and pitch was stamped on there as well. 13.5" Dia. 16 pitch which is a reference number only and has no correlation with the diameter and pitch.

I assume pitch reference on an inboard prop is same is I/O prop? 16 pitch equals 16" of linear travel to make one revolution?

So, next question, if you are trying to readjust pitch on an inboard boat, do you also change diameter as well?

[Vicseek]

My opinion is to always go for the larger engine if price isn't too much of a factor. True you could reprop the 537 with a 1235 on the smaller hp motor to get a better hole shot/acceleration. However, the same boat with the 343hp also reproped with a 1235 would be able to take on that much more weight. Something you would definitely have to test drive.
The 343hp motor is definitely a minimum on my RZ2 and I have the 1235 however when we are fully loaded with ballast and only 3-4 people she's slow to get on plane; definitely need people sitting in the bow. Going from the 537 to the 1235 took about 3-4mph off my top speed however the added acceleration/torque makes it worthwhile!
http://www.acmemarine.com/prop-list_ski-boat.php

From the website the
1235 has 14.5 dia and 14.2" pitch
537 has 13.5 dia and 16" pitch

So you see from that comparison the 1235 will travel less distance through one revolution (in a fluid); this is great for pulling/acceleration from low speeds since this prop will utilize the higher RPM hp/torque curve.