What are the best propellers for my 2x250hp rib?

[Fjordrafting]

My Scorpion is 29 feet and has 2x 250hp counterrotating Evinrudes. The boat is ment for chartering with jockeyseats for 14 people. I have been recomended Hydromotive fourblade IV OT 27"(Hydromotive.com). This one gives stearnlift rather than the IVX OT, which gives bowlift.

I am going to take delivery of the boat in April, so the engines haven´t been run in yet. I heard that they come with 19" Viper propellers and that i need to use them for 5 hours to run in the engines properly. Then I need new propellers. Is this right? Sounds expensive to me. Can I go directluy on a bigger Evinrudepropeller in order to save some few bucks?
Is there any experts out there who can help?
Martin

[eksrae]

hey there

we us 4 blade revolutions with 21 pitch on our 28' aliuminum rib with 250 yamahas.
as for differant props for break in?
never heard never done on any boat before

[Windchill]

try www.steeldevelopments.co.uk they are very knowledgeable

[Steel Dev]

Re your propellers

When the boat is set up the dealer usually supplies propellers that are suited to the engine boat configuration. It is very unusual to supply props for running in only and then expect the client to buy replacements. I would check this arrangement with the dealer.

There are several aftermarket propellers available to suit your engines. Because they are counter rotating it does limit you a little in choice. Hydromotive propellers are very good but expensive. Any of the Mercury range can be adapted to fit your evinrudes. Also some of the Solas range are available as counter rotating.

What I would suggest is you speak to your dealer again about the props that come with the engine. When you have tried the boat out of a while with different loadings and different conditions you will get an idea about how the props are performing, try and make a note of what engine rpm you get in different conditions before you consider changing the propellers. You don't want to end up buying loads of different sizes. I would have thought that 27" pitch is too high with 14 people on board I would suggest something nearer to 23" or 25" pitch would be better depending on how high the engine is mounted.

Let us know how you get on.

[Dirk Diggler]

Oh I do like to here about a prop problem. As for finding experts, good luck.

However, the running in on 19" Vipers for 5 hrs then changing to bigger props is absolute tosh!!!!! Part of the PDI is to note WOT, with 19's you would be bouncing off the limiters!!!

Hydromotives are an excellent prop and with the dollar being so week at the moment they are excellent value for money. Merc props are also excellent and have a huge range to choose from.

As for reccommending what to go for, I would have thought that a good starting point would be to ask Graham at Scorpion.

What are the ratio's, and what sort of speed are you expecting with this set up. Are the motors being supplied/fitted over here, if so you should be able to borrow props from Jets Marivent.