prop choice

andyxs · 20-11-2007, 09:32 AM

have a 7.2 meter warped v xs rib with a 200 merc running a 21" 4 blade lazer 2 prop and i get 58mph at 5000ish revs with a little chine walk. got the ecu print off and its never been over 5400 revs. and less than 5 mins over 5000 in 250 hrs. wondering if i need to go down a pitch or alter prop type? have no experience with props. first instinct is to go down a pitch but was wondering what you guys think.

Cookee · 20-11-2007, 10:34 AM

Quote:

Originally Posted by andyxs

have a 7.2 meter warped v xs rib with a 200 merc running a 21" 4 blade lazer 2 prop and i get 58mph at 5000ish revs with a little chine walk. got the ecu print off and its never been over 5400 revs. and less than 5 mins over 5000 in 250 hrs. wondering if i need to go down a pitch or alter prop type? have no experience with props. first instinct is to go down a pitch but was wondering what you guys think.

It's a good place to start, especially if you can borrow one - I think there are a couple of people up your way on the tube site that may be able to help - have you tried moving any heavy moveable things towards the back of the boat? Anchor for instance?

andyxs · 20-11-2007, 11:08 AM

will try and borrow one for the weekend. think the boat yard has a couple of 19s i could try. any idea on type for top end. have no experience but cleaver/chopper etc and what can i expect from them? know im asking alot here as well. thanks cookie.

Cookee · 20-11-2007, 01:48 PM

Quote:

Originally Posted by andyxs

will try and borrow one for the weekend. think the boat yard has a couple of 19s i could try. any idea on type for top end. have no experience but cleaver/chopper etc and what can i expect from them? know im asking alot here as well. thanks cookie.

Engine height may also be an issue - it should be revving a bit more than that with a 21 really - Are you sure it's a 4 blade laser? As far as I know they are all 3 blades - could it be a Trophy or something else? A Raker is generally a faster prop (we used a modified one at Coniston), but you have to consider what you will be losing - for instance moving the engine up a couple of bolt holes and changing propellers may make it less useful for skiing etc.

andyxs · 20-11-2007, 02:40 PM

good point. think i will keep it simple to start with and see where it gos but defintaly guna get hold of a 19". thanks cookee.