General prop questions

[Tuckered]

I recently had some work done on my motor, a Mariner 75 hp, pro series, 1996, 3 cylinder (has oil reservoir separate from the fuel tank). The motor sits on a Bass Tracker Magna 17, "V" bottom boat. Took it down to the Independence, Missouri Bass Pro-shop because of motor problems and not knowing who to take it too. Well, they couldn't figure out that the "trigger" was bad, replacing fuel pumps, switch box, regulators etc. Finally, found out about a place in Boonville, Missouri (a small town) that has much smarter/honest persons working there, that fixed my motor. (Big thank you to them!) Anyhow, they mentioned that there are some vibrations coming from the prop; that it should be repaired or replaced, sometime in the future. The writing on the propeller states: SOLAS MYTH and D 3X13x21R. I think it's OEM. Looking at the links here, at iboats, plus, not being familiar about this stuff, I want to see if I'm correct: It means 3 blade, 13" diameter, 21 inch pitch with a right hand/normal rotation. But I see others talking about slippage. What's that? It's just an ole fishing boat. . . Looking for a new prop. I saw a Solas Amita number 1411-130-21. Is that the correct one and is there anything that should also be replaced at prop changing time? Thank you,

 

[jestor68]

How long have you owned this boat?

What sort of WOT rpm does it turn with that 21 pitch prop?

I ask because the Mercury prop selector comes up with a 17 pitch prop for that boat/motor combo.

Slip is the difference between the theoretical speed a particular prop can achieve and the actual speed it achieves. A boat like yours might expect a slip factor from 10-13%.

 

[Tuckered]

I'm sorry for not responding. . . I've had computer issues and my motor is messed up again. Had a boat with a skier cut me off. Then the skier fell in front of my boat, causing me to make a sharp left turn, to avoid her. At the same time, I throttled down, too fast and accidentally put the motor in reverse. It's messed up now. I think the rpm gauge was reading between 4 and 5k, on the gauge, at top speed of 40 mph. (Speed checked by several iPhone apps.) I tried to download a picture, but the site keeps saying it exceeds the limit. Not sure why.

 

[Tuckered]

I've had computer issues. Sorry for not responding faster. When topped out, the rpm gauge runs, I think, 4 and 5k. I'd tell you for sure, but because it's broke down, I can't say exactly. I had a boat with a skier cut me off, to avoid the skier, which fell in front of my boat. I had to take emergency maneuvers. I unintentionally put the motor in reverse, while making a hard left turn. This screwed up the lower unit. I'd show a picture, but the site says it takes up too much memory.

 

[steelespike]

There may be a photo tutorial somewhere on the forum.
Near as I can tell you need to use a host site.
Do you know the gear ratio?I guessed 2.33 ,guessed 13% slip came up with 5387 rpm at 40 mph.
Guessing is not usually very accurate.
How was the performance? Hole shot,response to added weight?

 

[Tuckered]

The performance was flawless. 40 mph down the lake. I wish I could give you more details. But I do not know the gear ratio. I would assume it's "original". I never tinker with that stuff; I just don't know enough about that. The boat is in the shop, I'll take a look at the tac when I get it back and ask them about the gear ratio.

 

[steelespike]

Solas props have a good reputation.The number you listed should work but I can't tell you how it compares with your present prop.