Reply
 
Thread Tools Search this Thread
 
Old 26 April 2008, 16:23   #11
Member
 
Country: UK - England
Town: Southampton
Boat name: SMH Rib / War Shot
Make: Ribtec / Scorpion
Length: 4m +
Engine: 10hp Yam / 150hp opt
Join Date: Sep 2003
Posts: 1,894
RIBase
Outward turning

Outward turning - clockwise on stb, anti-clockwise on port.

Gives more predictable handling but might not give the best speed.

Imagine the boat in the air leaning over to starboard - only the starboard prop is in the water. If it's turning clockwise it will tend to level the boat. If its turning the other way it will tend to increase the lean.
__________________

__________________
Searider is offline   Reply With Quote
Old 26 April 2008, 16:31   #12
Member
 
Country: UK - England
Town: NW& wherever the boat is!
Boat name: depends on m'mood!
Make: Humbers/15-24m cats
Length: 6m +
Engine: etec130/big volvos
MMSI: many and various
Join Date: Nov 2001
Posts: 1,815
Quote:
Imagine the boat in the air leaning over to starboard - only the starboard prop is in the water. If it's turning clockwise it will tend to level the boat. If its turning the other way it will tend to increase the lean.
oooh - as explanations go I really do like that one!
__________________

__________________
Dave M
www.wavelengthtraining.co.uk
wavelength is offline   Reply With Quote
Old 28 April 2008, 06:40   #13
Member
 
Cookee's Avatar
 
Country: UK - England
Town: Salcombe, Devon, UK
Boat name: BananaShark
Make: BananaShark
Length: 10m +
Engine: 2xYanmar 260 diesels
Join Date: Mar 2003
Posts: 4,225
As Dirk said turning out is the convention for regular boats - turning in can give more speed as others have said, often with more nervous handling, this is as a result of getting more stern lift with the props turning in - Searider - great story where did you get that one from?
__________________
Cookee
Originally Posted by Zippy
When a boat looks that good who needs tubes!!!
Cookee is offline   Reply With Quote
Old 28 April 2008, 08:29   #14
Member
 
Simon B's Avatar
 
Country: UK - England
Town: Leicester
Boat name: Vixen
Make: Ribcraft
Length: 6m +
Engine: Suzuki OB 175
MMSI: 235071839
Join Date: Jun 2004
Posts: 1,621
So how do they do it on aircraft with props?
__________________
New boat is here, very happy!
Simon
www.luec.org
Simon B is offline   Reply With Quote
Old 28 April 2008, 12:52   #15
Member
 
Country: Other
Town: Stanley, Falkland Is
Boat name: Seawolf
Make: Osprey Vipermax 5.8
Length: 5m +
Engine: Etec 150
Join Date: Mar 2006
Posts: 3,688
Quote:
Originally Posted by Simon B View Post
So how do they do it on aircraft with props?
By the time the props touch the water on a plane you have usually got bigger problems to worry about
__________________
A Boat is a hole in the water, surrounded by fibreglass, into which you throw money...

Sent from my Computer, using a keyboard and mouse
BogMonster is offline   Reply With Quote
Old 29 April 2008, 10:19   #16
Member
 
Cookee's Avatar
 
Country: UK - England
Town: Salcombe, Devon, UK
Boat name: BananaShark
Make: BananaShark
Length: 10m +
Engine: 2xYanmar 260 diesels
Join Date: Mar 2003
Posts: 4,225
Quote:
Originally Posted by BogMonster View Post
By the time the props touch the water on a plane you have usually got bigger problems to worry about
............ And they're not that close either!
__________________
Cookee
Originally Posted by Zippy
When a boat looks that good who needs tubes!!!
Cookee is offline   Reply With Quote
Old 30 April 2008, 04:38   #17
Member
 
Country: UK - England
Town: Southampton
Boat name: SMH Rib / War Shot
Make: Ribtec / Scorpion
Length: 4m +
Engine: 10hp Yam / 150hp opt
Join Date: Sep 2003
Posts: 1,894
RIBase
Quote:
Originally Posted by Cookee View Post
As Dirk said turning out is the convention for regular boats - turning in can give more speed as others have said, often with more nervous handling, this is as a result of getting more stern lift with the props turning in - Searider - great story where did you get that one from?
It's just the same as offsetting, in a single installation, a right hand rotation to starboard and a left hand rotation engine to port.

Not really a "story" was just trying to simplify the explanation.
__________________
Searider is offline   Reply With Quote
Old 30 October 2008, 18:45   #18
Member
 
Country: France
Town: Cannes
Boat name: midkat 550
Make: apoge
Length: 5m +
Engine: 2x50 Tohatsu
Join Date: Jan 2008
Posts: 126
clockwise rotation on portside and counter on starboard lifts the bow, this is true on monohulls as on catamarans.

Reciprocating that gives a more level fly, this can be used to compensate for unwanted hull behaviour
__________________
yorfuoj is offline   Reply With Quote
Old 31 October 2008, 18:34   #19
Member
 
Country: UK - Scotland
Town: wormit
Boat name: lots of them
Make: various
Length: no boat
Engine: all types
Join Date: Dec 2004
Posts: 388
If the engines are used and before you even think about fitting them. check the propellers are on the correct gearboxes. What happened here was a pair of engines were delivered but the propellers were on the wrong engines. There were no markings saying counter rotation or anything to that effect so engines were fitted and sure enough everything worked but yes they were both running in reverse gear. The standard box was the first to blow. Repaired then did same again. It was only noted when the clockwise propeller was shown that everything clicked what was going on. This was on mercury 200's It takes 5 minutes to check box but time well spent. Think about it its like a double wammy!
__________________
Davie is offline   Reply With Quote
Old 31 October 2008, 19:59   #20
Member
 
Country: UK - Wales
Town: West Wales
Make: Vipermax 5.8, SR4.7
Length: 5m +
Engine: 150 Opti, F50EFi
Join Date: Sep 2005
Posts: 6,298
Quote:
Originally Posted by Davie View Post
.... What happened here was a pair of engines were delivered but the propellers were on the wrong engines. ...
I've heard it all now....
__________________

__________________
Downhilldai 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 14:07.


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