prop questions for bass boat

[jpdodd]

I'm new to this forum, but I was wondering if some of you guys could help me out with a few questions. Before I ask, here's my boat information:

2006 Bass Tracker Proteam 175
40 HP mercury - 4 stroke EFI
10 1/2" x 13 pitch Black max aluminum prop
Gear ratio 2.00 - 1

Average load - 5200 rmp - max speed (by GPS) 24-25 mph
WOT recommendations for this motor are between 5500-6000

I just bought the boat about a month ago, and have had it out several times. It takes a little while to get up on plane, but does alright when it's there. The owner I bought it from said that the fastest he was able to get the boat was about 30 mph. (Which is a little lower that what I calculated when using several methods found on different websites)

Theoretical max speed = (RPM x pitch) / (1056 x gear ratio) = 32 mph at 5200 rpm

Or this other one that I found: (170) / (sq.rt.(weight / hp)) x 1.15 = 32.3 mph

SO, my questions are as follows:

1. The prop is a little beaten up (chips on all blades are not deeper than 1/8 to 3/16 inches). How much would the condition of the prop affect the top end speed and RPM's? Performance otherwise seems o.k. but I'm new at this...

2. I will be looking to replace the prop in the spring, but I'm not sure what to go with. I know that by reducing the pitch I can increase the rpm's and therefore speed, but I'm not sure sure how much to reduce because of the damage of my current prop.

3. I was looking at getting the SE sport 200 hydrofoil to improve planing time.
Found here:
(http://www.cabelas.com/fryprod2-1/7...-F5D2-DF11-82EF-001B21631C34&mr:referralID=NA)

Does anyone have any experience of what that might do for my speed/holeshot given my particular boat?

Thanks! I know this is kind of a long post, but I've been doing a ton of searching and can't find the info that I need.

jon

 

[steelespike]

Re: prop questions for bass boat

Your boat is under powered,your figures disregards slip so not likely to make even 30 mph but we can tweak things to be sure you getting the most speed possible.
The antiventplate(just above the prop) should be visable on plane.Usuall about an inch above the bottom.
Your prop probably isn't hurting a lot but surely is hurting some.Best way to get a base line test is to have the prop repaired and make a few runs lightly loaded.
Being sure trimmed carefully.Get us the max rpm and speed.
A set of trim tabs either active or passive ,like Smart Tabs,are a better option than a foil.Prop selection will also help hole shot.Be sure the throttle opens all the way at the carb.If tanks and batteries are in the stern moving something forward will help.

 

[jpdodd]

Re: prop questions for bass boat

I will have to take it out and see where the antiventplate (cavitation plate?) is when I'm on plane... The earliest I may be able to get out is this weekend.

What do you mean about "Being sure trimmed carefully"?

 

[steelespike]

Re: prop questions for bass boat

If the boat is on a trailer with the plate parallel with the keel use a straight edge along the keel to the plate to measure.
Trimming down/in for hole shot and trim out/up for speed.No power trim.You'll have to comprimise, for your test trim out for best speed.

 

[jpdodd]

Re: prop questions for bass boat

Gotcha. I'll check that out.

As far as the prop, should I repair this one before I decide to buy a new one with a different pitch? I have noticed that with different weights in the boat, the rpm's are different. Does the condition of the prop affect the rpm's?

I don't want to buy a new prop with a lower pitch and end up with too many rpm's...

 

[steelespike]

Re: prop questions for bass boat

Yes the condition of the prop affects rpm.The affect would depend on what type and extent of damage.The amount of weight and the placement affect rpm and speed as well.Sometmes added weight might require a motor trim change.If you get the prop fixed and get the base line numbers we should be able to tell a better prop.If a different prop is in order you can use the old one for a spare backup.

 

[jpdodd]

Re: prop questions for bass boat

I guess the next step is to find a repair shop and see how much the repairs will cost for the prop.

Thanks for taking the time to answer my questions.

 

[steelespike]

Re: prop questions for bass boat

Around here(central NY) about $40.