Sea-Dated

I am wanting to upgrade the props on my 1990 29' Fountain w/ twin 365hp 454's but do not know what pitch to buy. I currently have the stock (I assume) 3 blade bravo props and am getting about 69mph gps out of her. I am wanting 4 blade but do not have the time or money to go through props trying to find the best one. Has anyone done this and if so, can you recommend the right props for my boat.
Thanks

throttleup

If you can tell me the pitch of the props your are currently running I will try to assist you. I have a testing program available that will allow you to try before you buy. If you can get me some data I can run some numbers for you.

What is your WOT RPM?
What is your WOT MPH via gps?
What is your gear ratio in your outdrive?
What pitch are your propellers?

Julie

99fever27

Julie I am thinking of having a set labbed..do you think I would see any noticable gains.
1999 27' Fountain step hull
73mph on gps turning 5000rpms
currently running a stock 26 Bravo rh
low hr hp500 all stock setup.
If so what is your current turn around time?
Cheers, Matt

Sea-Dated

WOT via GPH is 69.4 is the best I have gotten. I usually get around 68 every time.

I do not know what the pitch of the current props are. How can I find that information?

I am not sure what the drive ratio is either. They are stock Bravo 1's.

I will find out what the WOT RPM's are this weekend.

I have been told that a 4 blade prop will hurt performance on a non stepped hull over a 3 blade prop. Why is this?

bbladesprops

outcastyj,

Most likely the props will be stamped with a part number and or a pitch somewhere on the propeller. Look on the outside of the exhaust tube between the blades and inside on the inner hub by the nut. Most likely the drive ratio is 1.5:1. Running some numbers will help us to determine that if you can't find the information. As far as 4 blades on deep V's hurting performance, it may depending on your goals. The 3 blade Mirage Plus props will most likely give you the biggest top end numbers but the 4 blade props can give you benefits in other areas like ability to get on plane and cruise speeds. $ blade props can be worked to give all the low and mid range benefits and still provide good top end numbers. To answer your question, 4 blade props give more stern lift than 3 blades and deep V's prefer bow lift over stern lift.


99fever27,

With a slip % under 9 and the rpms at 5000 with that motor, you are in the perfect spot to gain big from Lab Finishing!

99fever27

With a slip % under 9 and the rpms at 5000 with that motor, you are in the perfect spot to gain big from Lab Finishing!

alright now you got me excited...whats your turn around time?
and please define big!

bbladesprops

This time of the year turn around can be 3-4 weeks.

By big I mean 4-5 mph. I was using 1.5 as your gear ratio.

99fever27

Thanks Brett,
1:5 is correct..if I can expect those kind of gains than im definatly sending them to you to get labbed. 3-4 weeks? ouch..... My have to rethink this. I could probably handle two weeks while im doing some paint and graphics but much more would drive me crazy.

Sea-Dated

I currently have 25 pitch 3 blade mirage props. Unfortunately it was raining all weekend and I did not even get the boat out so I did not get to find out what the RPM's are at WOT.

Sea-Dated

According to the performance report issued by Fountain when the boat was new it would run 77 @ 5100RPM. I am sure that is by speedo and not GPS so maybe 75mph. That was with 14.5 X 25 Mirage 3 blade props on Bravo ones with a 1.5:1 ratio and 16" X D. Does this help? Now, 16 years later, I am not even getting 70 out of her and I know the props have some dings in them and are 16 years old. How bad can that hurt my top end? Suggestions?