85 hp prop questions

[henrymox]

hi ive got an 89 bayliner capri 1700 with an 85 horse force. im looking to maybe get a stainless prop for it. im just wondering what the stock size and pitch is for this boat and motor combo and if anybody can recommend a size and pitch. im not sure whats on it at the moment and its in storage right now and i cant get to it to check it. from what ive read it is very important to get the right pitch for what the motor was designed for and i want to make sure i get it right. also does anybody think its worth getting a stainless prop? some people are telling me it does make a noticeable difference in performance but i dont really know. i use the boat for a little bit of cruising and a little bit of tubing now and then. right now the boat tops out at 32mph. any help you could give me would be great thanks.

 

[roscoe]

Re: 85 hp prop questions

You should probably ask this question in the "prop forum".

There was no "stock" prop.
But someone with the same boat may be able to tell you what they are using.

Correct prop selection is based on maximum engine rpm's achieved at wide open throttle (wot).

Prop pitch is selected to move the max wot rpm's up or down, within the recommended range from the manufacturer.

Additional items that influence the prop selection will be:
size and shape of the hull
weight of the load you are carrying
height of the engine on the transom
trim setting on the motor
desired performance

So, what are your wot rpm's with a light load in the boat?
What is the diameter and pitch of your current prop?
And, how many hundreds do you want to spend to possibly gain a couple mph?


For your reading pleasure:
http://forums.iboats.com/bbBoard.cgi?a=viewthread;fid=36;gtid=1035562

 

[Matthew A.]

Re: 85 hp prop questions

It's been my experience with my 85 hp force on my 17 foot capri that the stock prop 3 blade semi clever, 13.75" x 17" pitch has been the best prop for the boat. I've run several different props on this boat with this motor. 4 bladed, adjustable pitch poly props that break off blades upon contacting anything other then stray eel grass strands or loose kelp fronds. A 19" pitch 3 bladed michigan prop...too much for the motor. To a stainless 3 bladed cupped in a 14" dia. x 17" pitch prop. While it was great off the line...and more responsive...still just a tad too much pitch. Plus, it tended to ventilate more then the stock prop in tight cornering. The biggest gain in getting my boat up on plane quickly as well as saving me loads of money on poor fuel milage was installing trim tabs on the port and starboard sides of the transom. Like buying a brand new boat. 8)