Reply
 
Thread Tools Search this Thread
 
Old 20 November 2007, 09:01   #1
Member
 
Country: UK - England
Boat name: llyn raider
Make: xs
Length: 7m +
Engine: 1 200hp merc
Join Date: Nov 2006
Posts: 211
prop choice options

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. looking for a bit more on the top end if poss as acceleration is already good.
__________________
andyxs is offline   Reply With Quote
Old 27 November 2007, 00:21   #2
Member
 
Country: Australia
Town: old bar
Boat name: efo
Make: avon
Length: 4m +
Engine: yam60hp 2stroke
Join Date: Oct 2007
Posts: 23
chine walk

chine walk will happen for a number of reasons,,a starting test is to trim up and see if theres any play in your steering,also sum engines have anti vibration mounts,(rubber),,and at speed with lots of trim they can cause chine walk as the mounts flex,,,mottor wobble,,if thats ok then see where the water is breaking,,,your engine may be to low on the transom engine height adjustment can also yeild good economy figures as theres less drag,so u get better fuel economy with more speed when needed,,its a matter of trial and error but much cheaper than buying props to try
__________________
truble is offline   Reply With Quote
Old 27 November 2007, 17:53   #3
Member
 
Country: UK - England
Town: Gloucestershire
Boat name: Osprey
Make: Osprey Vipermax
Length: 5m +
Engine: E-tec 300 G2
MMSI: TBC
Join Date: Dec 2006
Posts: 4,020
Andy it its top speed you are after you may want to try a 3 blade prop?

As I understand 4 blades give you better hole shot at the cost of top end speed.

What height is your anti ventilation plate in relation the bottom of the transom?

Chris
__________________
Chris is offline   Reply With Quote
Old 28 November 2007, 15:48   #4
Member
 
martini's Avatar
 
Country: UK - Channel Islands
Town: jersey
Boat name: Martini II
Make: Arctic 28/FC470
Length: 8m +
Engine: twin 225Opti/50hp 2t
MMSI: 235067688
Join Date: Jun 2005
Posts: 3,030
The first thing I would do is raise the motor on the bolt holes and see what happens. It's bound to raise the top end rpm but may not raise the top end speed. Could also cause slippage but at least it doesn't cost anything to try as opposed to buying another prop for £400.
__________________
martini is offline   Reply With Quote
Old 28 November 2007, 16:45   #5
Member
 
Country: UK - England
Boat name: llyn raider
Make: xs
Length: 7m +
Engine: 1 200hp merc
Join Date: Nov 2006
Posts: 211
thanks guys will have a play with the height
__________________
andyxs is offline   Reply With Quote
Reply


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off




All times are GMT. The time now is 15:02.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2024, vBulletin Solutions, Inc.