Prop conundrum

Mike C · 12 April 2005, 10:23

For some time I have been meaning to change my 23" ali prop.... which only achieves 400 - 500 revs BELOW the recommended WOT, for a smaller pitched steel one.

Having finally decided to go ahead, the main choice seemed to be between a high rake Laser II or a more standard Vengeance. Andre has the Laser II and swears by it, but sought opinion seemed to favour the Vengeance for my weight diesel boat. Whichever of those 2 props I chose, in theory the reduction to a 21" pitch should give me the required extra 400 revs to get to correct maximum WOT

However, I then rang Steel Developments who recommended a 3rd option of the larger diameter 'Titan' prop, (apparently the Solas version of a Mirage), in 21" pitch. I was persuaded and bought one. Unfortunately, this has turned out to be not right for my boat; the extra diameter producing only 100 revs more. Due to the fact that, (for good theoretical reasons), Steel Developments suggested that prop, wrongly as it turned out, they have agreed to change it for another of my choice. Their suggestion now is that a 19", ‘Titan’ prop would be best.

So here is my conundrum.... Which should I choose? Steel Developments tell me they will only change it this one time, so do I take their advice and get a large diameter 19” prop. Go with the more common advice and get the 21" pitch steel version of the one I have, (i.e. the Vengeance) or follow Andre’s lead and get a Laser II?

Whichever I do, I will probably wish I had gone for the other but does anyone have any experience of the Titan… or the Vengeance versus the Laser II etc… on a 1,200 kilo diesel RIB. Andre has kindly offered to let me try his Laser II – (thanks mate!) but after that, I am choosing blindly and I’m stuck with my decision…..

Does anyone RENT props????

Thoughts appreciated!

Mike C

Pete7 · 12 April 2005, 10:46

Stick the Ali back on so you don't damage or mark the one from Steel Developements, try Andre's prop and make the decision once you have seen the results.

Pete

Scary Des · 12 April 2005, 10:50

I think that Steel Devs were doing a try before you buy at last year Ribex, might we worth seeing if they are doing the same this year

. Des

Mike C · 12 April 2005, 11:38

Thanks for the comments lads.....

Pete7

The Ali is back on.... The steel one is in a box waiting to be posted back to Steel Dev. I will try Andre's prop but I won't know if its better or worse than the Vengeance or the one Steel Dev is now recommending cos I have to choose which one I want before I can try them!

Scary Des,

Steel Dev may have been offering that at Ribex last year… and I must admit I was hoping they would do something like that for me…. But they are adamant they won’t. I have to accept, I am lucky they are taking the wrong one back!

There must be someone who RENTS props!

Mike C

codprawn · 12 April 2005, 12:32

Well JK - how about it??? Maybe a prop swop shop or similar???? Or maybe a pool prop programme where people can rent spare props off each other for a small fee???

Don't know how it would work but I am sure you could come up with a solution!!!!

Mike C · 12 April 2005, 12:52

Now THERE'S an idea......

Searider · 12 April 2005, 17:44

Mike,

I have a 19" Vengence you can try if you like.

For my boat, however, the Laser II is better (faster and less cavitation / ventilation).

Also, send Jon Adlard a PM - he's got an identical boat to you and may be able to offer some advice.

Regards

Richard B · 12 April 2005, 17:49

You can try my S/S Solas Titan 19" if you like, but as it's got a Yamaha hub I don't think it will fit your Mercruiser.

I'm not 100% happy with it, and will be fitting my other prop, a Yamaha "Black Max" Stainless Steel this season, unless I can find someone who will lend me a LaserII to try.

Louise · 12 April 2005, 17:57

Quote:

Originally Posted by Mike C

I have to accept, I am lucky they are taking the wrong one back!

Why do you consider yourself to be 'lucky'? On their advice you bought a prop which was not the right one!

IMHO surely they are obliged to replace the prop? Personally, I would ask for a refund because (IIRC) once you have accepted an exchange you have no legal grounds to ask for a refund later if the goods are still not right.

codprawn · 12 April 2005, 19:22

Quote:

Originally Posted by Louise

Why do you consider yourself to be 'lucky'? On their advice you bought a prop which was not the right one!

IMHO surely they are obliged to replace the prop? Personally, I would ask for a refund because (IIRC) once you have accepted an exchange you have no legal grounds to ask for a refund later if the goods are still not right.

Couldn't agree more - it just goes to show prop choice is something of a black art as there are so many variables - also the way you use the boat also has a big impact.

Hightower · 12 April 2005, 19:58

Quote:

Originally Posted by codprawn

Couldn't agree more - it just goes to show prop choice is something of a black art as there are so many variables - also the way you use the boat also has a big impact.

Could also agree, don't know about bigger RIBs but I use two different pitches of prop depending on load carried.

Andy

jwalker · 12 April 2005, 20:57

Quote:

Originally Posted by codprawn

Couldn't agree more - it just goes to show prop choice is something of a black art as there are so many variables - also the way you use the boat also has a big impact.

Not in this case, they just got it wrong. Mike C new better and he should have relied on his own knowledge. Increase of 400-500revs required. Rule of thumb 200rpm/1" pitch change. Therefore, 23" down to 20"/21"... fine but Mike said Steel Developments recommended increasing the size of the prop. This is obviously going to drop the revs. Doh.

Hightower · 12 April 2005, 21:04

I'd tell Steel developments that I wanted my money back and go prop borrowing, then after all that borrowing I'd take a look at ebay as there seems to be plenty of bargain props on there!

Mike C · 12 April 2005, 21:12

Thanks for the replies...

Searider...
Thanks for the offer. The theory is that for the Vengeance, I really need a 21"... but I may well take you up on it just to see! As you have a petrol o/b, then yes, the Laser probably will be better. It MAY be different with my diesel!

Richard B....
Thank for your offer.... Trust you to buy a Yam! Still that’s more Alan's fault really... and he's in the colonies! I have big hammer... Maybe if we hit it hard enough it will fit? I will answer your PM re the Solas and your previous problems

Louise...
Well I could go down that road but I do still want a new prop. To be fair, Steel Dev did offer to change it for another without any prompting.... and as we have said, props are a black art. Even with a re-fund, I'm still in the same position.... unless I can find a company that will do an exchange system! That would be the ideal and I'd happily pay a bit more for that facility.

Codprawn & Hightower...
The performance I quoted earlier is fairly heavily laden. With one person on board and only a little fuel the 23" ali is reasonable. Heavily laden, I would be happy with another 200-300 revs... which would be about 200 below what WOT should be. Overall though I need a lower pitch.

Mike C

Pete7 · 12 April 2005, 21:15

Err, bottle of Port says Richards Yam prop will fit but might need a spacer to adjust the distance to the hub.

Pete

Mike C · 12 April 2005, 21:18

....JWalker...

Not exactly.... I dropped PITCH size to 21" but the increase was in DIAMETER. This would seem to counteract the pitch drop to produce something that gives about the same WOT revs as my ali. That’s why they suggested dropping another 2" in pitch for the Titan. The theory is OK.... Its the practice that worries me! I may well end up getting a Laser II if Andre's works well on my boat just because I will then be sure what it does... even though the Vengeance or 19" Titan may actually have been better.... But I can't find out!
Mike C

Richard B · 12 April 2005, 21:19

Quote:

Originally Posted by Pete7

Err, bottle of Port says Richards Yam prop will fit but might need a spacer to adjust the distance to the hub.

Pete

Sounds like the start of a prop swop shop!

Mike C · 12 April 2005, 21:21

Richard....

Whatya doin on the weekend of the 23 & 24th April?

Pete7 · 12 April 2005, 21:25

Quote:

Originally Posted by Richard B

Sounds like the start of a prop swop shop!

Andres boat can't be that different to the Humber, but I would get me hands on every prop available and spend an afternoon testing. In fact it would make quite a good article on the effects of different props on a boat.

Rogue Wave might have a Laser 21 too thinking about it.

Pete

Richard B · 12 April 2005, 21:29

Quote:

Originally Posted by Mike C

I may well end up getting a Laser II... even though the Vengeance or 19" Titan may actually have been better....

I've never read anything on RIBnet or anywhere else to suggest that either a Vengeance or a Titan would perform any better than a Laser II.

Quote:

Whatya doin on the weekend of the 23 & 24th April?

Swoppin' props?

P'raps a bit cheeky, but I wonder if we could persuade Duncan (Searider) to come along with a Vengeance or Laser II to compare to the Solas? All we would need now is a supply of spacers... Pete - IIRC you once mentioned that Lee Fairweather keeps them in stock? If so I might be able to pick some up one lunchtime.