Reply
 
Thread Tools Search this Thread
 
Old 11 September 2009, 15:07   #21
Member
 
chewy's Avatar
 
Country: UK - England
Town: Up Norf
Make: Avon SR4,Tremlett 23
Length: 4m +
Engine: Yam 55, Volvo 200
Join Date: Apr 2007
Posts: 5,217
Quote:
Originally Posted by JSP View Post
Jesus!
You also have prop slip, you need a little bit but not too much.
__________________

__________________
chewy is offline   Reply With Quote
Old 11 September 2009, 16:12   #22
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: 4,013
Quote:
Originally Posted by JSP View Post
When turning tight, the prop can slip very easily. Also can loose grip when things get lumpy
Losing grip is probably going to be down to the following

- Engine is trimmed out (most will slip when running trimmed out when you turn tight)
- Prop is damaged (even small nicks and dents will cause cavitation and the prop will loose grip more easily)
- Engine too high on the transom

Post a pic of your prop so we can see what condition it is in....
__________________

__________________
---------------------------------------------------
Chris Stevens

Born fiddler
Chris is offline   Reply With Quote
Old 11 September 2009, 16:20   #23
Member
 
Country: UK - Wales
Town: Here
Boat name: doggypaddle
Make: Avon 5.4 Searider
Length: 5m +
Engine: yamaha 80
Join Date: Jul 2007
Posts: 1,107
yamaha K series 19 or 21 will be about spot on i would say.
Most yam90s on seariders run 19" props, you should be able to swing a 21 with the extra power of the 115.
NOS4r2 has a 21 on his SR at the moment cos the hub on his 19 went.
thats OK with an 85 rpm wise (just) should be dangerous fast with the 115
Perhaps if there time at the gathering and you can persuade NOS you can try the 21, he can use my 19, and i will run on a 17" i have?
__________________
I am usually not as green as i am cabbage looking.
doggypaddle is offline   Reply With Quote
Old 11 September 2009, 17:04   #24
JSP
Member
 
Country: UK - England
Town: Southport
Boat name: Qudos
Make: 5.4 Searider
Length: 5m +
Engine: Yam 115 V4
MMSI: 235068784
Join Date: Sep 2008
Posts: 3,930
Quote:
Originally Posted by Chris View Post
Losing grip is probably going to be down to the following

- Engine is trimmed out (most will slip when running trimmed out when you turn tight)
- Prop is damaged (even small nicks and dents will cause cavitation and the prop will loose grip more easily)
- Engine too high on the transom

Post a pic of your prop so we can see what condition it is in....
Thanks Chris,
I always trim in to do the turn. True it could be trimmed out a bit to far when I've lost grip in the waves.
Prop is fine, no dings.
Didn't think about the engine...Will take some pics as soon as
__________________
JSP is offline   Reply With Quote
Old 11 September 2009, 17:06   #25
JSP
Member
 
Country: UK - England
Town: Southport
Boat name: Qudos
Make: 5.4 Searider
Length: 5m +
Engine: Yam 115 V4
MMSI: 235068784
Join Date: Sep 2008
Posts: 3,930
Quote:
Originally Posted by doggypaddle View Post
yamaha K series 19 or 21 will be about spot on i would say.
Most yam90s on seariders run 19" props, you should be able to swing a 21 with the extra power of the 115.
NOS4r2 has a 21 on his SR at the moment cos the hub on his 19 went.
thats OK with an 85 rpm wise (just) should be dangerous fast with the 115
Perhaps if there time at the gathering and you can persuade NOS you can try the 21, he can use my 19, and i will run on a 17" i have?
Bugger, my boats not coming to the gathering mate. Thanks though
I've seen a few new 21" K series for sale. Wonder if I should just take the plunge?
__________________
JSP is offline   Reply With Quote
Old 11 September 2009, 17:11   #26
Member
 
chewy's Avatar
 
Country: UK - England
Town: Up Norf
Make: Avon SR4,Tremlett 23
Length: 4m +
Engine: Yam 55, Volvo 200
Join Date: Apr 2007
Posts: 5,217
Quote:
Originally Posted by JSP View Post
Bugger, my boats not coming to the gathering mate. Thanks though
I've seen a few new 21" K series for sale. Wonder if I should just take the plunge?
How come your mot bringing the boat mate, trouble with console?
__________________
chewy is offline   Reply With Quote
Old 11 September 2009, 17:13   #27
JSP
Member
 
Country: UK - England
Town: Southport
Boat name: Qudos
Make: 5.4 Searider
Length: 5m +
Engine: Yam 115 V4
MMSI: 235068784
Join Date: Sep 2008
Posts: 3,930
Quote:
Originally Posted by chewy View Post
How come your mot bringing the boat mate, trouble with console?
No and yes, Consoles glassed in but I've got my lads birthday party tomorrow, my girls on Sunday then their actual birthdays on Tuesday and Wednesday and bugger all time inbetween then and the gathering to finish it all off

But I may not be seariderless that weekend
__________________
JSP is offline   Reply With Quote
Old 12 September 2009, 06:14   #28
Member
 
Hightower's Avatar
 
Country: UK - England
Town: Fareham
Length: 6m +
Join Date: Sep 2003
Posts: 7,855
Once you've sorted the slip out buy adjusting the trim or engine height out the next figure I would be looking at is my cruising speed at a set RPM (say 3500rpm) and seeing what speeds I'm getting with different props.

It's all very well looking for the holy grail and getting maximum speed, but max speed doesn't always mean max speed at cruising RPM

If you could eek out another few knotts at you're normal cruising speed then think of the fuel savings and decreased travel time.
__________________
Andy

Looks Slow but is Fast
Member of the ebay Blue RIB cover club.
Hightower is offline   Reply With Quote
Old 12 September 2009, 06:37   #29
RIBnet admin team
 
Nos4r2's Avatar
 
Country: UK - England
Town: The wilds of Wiltshire
Boat name: WhiteNoise/Dominator
Make: Ballistic 7.8/SR5.4
Length: 7m +
Engine: Opti 225/Yam 85
MMSI: 235090687/235055163
Join Date: Jul 2005
Posts: 12,645
RIBase
Quote:
Originally Posted by Hightower View Post

If you could eek out another few knotts at you're normal cruising speed (assume you mean RPM) then think of the fuel savings and decreased travel time.
Erm, but that's making your engine labour.

Let me put it this way.
Basic principles:-

Your engine develops it's rated HP between the max rpm figures stated by the manufacturers.
If you can't rev to the rated RPM, you're not developing the stated HP and you're using more fuel per combustion cycle (but less cycles) to keep the same performance, yet losing acceleration and not doing your engine a whole lot of good.
__________________
Need spares,consoles,consumables,hire,training or even a new boat?

Please click HERE and HERE and support our Trade Members.

Join up as a Trade member or Supporter HERE
Nos4r2 is offline   Reply With Quote
Old 12 September 2009, 06:41   #30
Member
 
Hightower's Avatar
 
Country: UK - England
Town: Fareham
Length: 6m +
Join Date: Sep 2003
Posts: 7,855
OK then, I made the assumtion that people knew the engine should be operating within the WOT range which on some engines is as much as 1000RPM.

__________________

__________________
Andy

Looks Slow but is Fast
Member of the ebay Blue RIB cover club.
Hightower is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search

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





Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -5. The time now is 04:51.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.