Anyone tired of diameter & pitch questions yet?

[logartist]

I have an 18' Galaxie sst powered by 3.8 OMC/ Stringer outdrive. My brother struck the prop aground and chewed it up, plus took a small chunk off the tip of the rudder. I need to replace the prop, but while I'm going through the trouble, should I go with a different prop? Mind you I can't tell by looking at it what pitch it is, and it is parked about 150 miles away at my Dad's lakehouse. I haven't measured it, but the dia. looks no larger than 14" and is probably more in the 13" range. At WOT she makes about 40 mph at (I think) 4500 or so. However, the power trim is stuck down, so I can't get her bow up to find my 'true' top speed. I'm guessing I'd only get 5 mph more though. While I have people learning on her, I'd rather stay with aluminum or plastic for price and save the SS for when everyone's F-ups are out of their system, but she's a ski boat...Assuming my reccollection of WOT data etc. is close, point me at what you'd get for towing performance AND good top end...on a budget.

 

[Silvertip]

Re: Anyone tired of diameter & pitch questions yet?

Lets see -- you want to tow like a tow truck, run like a racer, and do it on the cheap. That ought to be a challenge, especially since everything you told us is an estimate? My suggestion is give us some "accurate" WOT RPM and speed data and we can give you some "reasonably accurate" suggestions. In the mean time, anyone want to step up for this one?

 

[walleyehed]

Re: Anyone tired of diameter & pitch questions yet?

Silvertip's response is spot-on...we can help with "known" numbers, but anyone thinking they can suggest a prop without those numbers probably hasn't spent enough time around them to actually be close.
I know it may be a pain in the rear but if you can get the numbers from the rear of the prop under the nut/washer, or possibly between the blades, that would be the most help to start with

 

[logartist]

Re: Anyone tired of diameter & pitch questions yet?

Your answers make sense and are what I expected...but I thought I'd troll for a genius prop wizard anyhow. I'll get the numbers posted and ask again later. Thanks.

 

[BF]

Re: Anyone tired of diameter & pitch questions yet?

I'd get the alum prop that you have on it now repaired. They can make it as good as new, even when it's missing chunks. Then, take the money you were gonna spend on a new prop, and get the tilt/trim fixed so you can keep the prop off the bottom!! After that, if there are performance issues, you can get a new prop and keep this one as a spare.

 

[logartist]

Re: Anyone tired of diameter & pitch questions yet?

That's a wise option...but how do they fix a chinked out prop? All I can immagine is grinding down all the fins so they balance. You can't tig-weld cast aluminum...can you? And I can't see trusting a braze job at high rpms...how do they do it?

 

[Bondo]

Re: Anyone tired of diameter & pitch questions yet?

You can't tig-weld cast aluminum...can you?

Ayuh,........ That's how it's Done.......

 

[Texasmark]

Re: Anyone tired of diameter & pitch questions yet?

Back before I went to SS on my 125 Johnny, you'd be surprised to see the B4 and after props that James Propeller Service in Dallas, TX. fixed for me. I don't know how they put all that new metal on and trimmed it out to look like a new OEM blade but they did.......well it looked new till the first time you use it and knock some of that spray paint off and see all the weld and machining marks.

Mark

 

[walleyehed]

Re: Anyone tired of diameter & pitch questions yet?

Your answers make sense and are what I expected...but I thought I'd troll for a genius prop wizard anyhow. I'll get the numbers posted and ask again later. Thanks.

I sure hope one comes along...I been wanting to know the magic to this for along, long time.....

 

[logartist]

Re: Anyone tired of diameter & pitch questions yet?

Well, if they can, they can, I guess. I'll look into it. Thanks for the tip...I wouldn't have considered it otherwise.

 

[Tredeb]

Re: Anyone tired of diameter & pitch questions yet?

I have seen shops that will just take your old prop and give you a rebuilt prop. You just have to pay the cost to rebuild yours and you are on your way in about 15 minutes.