 |
15 January 2007, 08:01
|
#1
|
|
Member
Country: UK - Channel Islands
Town: Guernsey
Boat name: Monkey Nutz
Make: Cougar R8 Sport
Length: 8m +
Engine: 350Sci Verado
Join Date: Aug 2006
Posts: 931
|
How Big?
After spending the last 8 weeks mucking about around the islands in less than desirable conditions, i have decided that maybe an aux engine would be a good idea.The question is how big and what sort is powerful enough to push the boat home safely.
I have an 8m Scorpion with a 250DI
Thanks
__________________
|
|
|
|
15 January 2007, 09:16
|
#2
|
|
Member
Country: UK - England
Town: Gosport
Boat name: April Lass
Make: Moody 31
Length: 9m +
Join Date: Aug 2001
Posts: 4,951
|
Tony, your Scorp will only travel at 6-7 knots at displacement speed (1.3 x the square root of the water line etc) so 10 - 15 hp will be fine unless you want to charge though the Alderney Race against the tide. A 4 stroke will enable you to connect the main take to the aux engine, a two stroke will need careful thinking about because of its 2 stroke oil supply, but will be lighter. Supply of new 2 strokes is now somewhat limited.
If your going second hand route ask to borrow it first, this would also confirm if you need short or long shaft.
Pete
__________________
.
Ribnet is best viewed on a computer of some sort
|
|
|
|
|
15 January 2007, 09:28
|
#3
|
|
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: 3,726
|
The rule of thumb is apparently 1hp per metre of boat so I guess 8hp minimum. Maybe a 9.9?
I needed a long shaft on my Humbug so I would think you'd need a long on a much bigger Scorpion.
__________________
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
|
|
|
|
|
15 January 2007, 09:37
|
#4
|
|
Member
Country: UK - England
Town: Bucks
Boat name: Blue & Ding Dong
Make: Ribeye,SR4 & Bombard
Length: 6m +
Engine: 115,50 & 15Hp Yams
Join Date: Feb 2004
Posts: 3,252
|
Tohatsu 9.8 two stroke, only 26Kg if weight is a issue?
Nick
__________________
|
|
|
|
|
15 January 2007, 10:08
|
#5
|
|
RIBnet admin team
Country: UK - England
Town: The wilds of Wiltshire
Boat name: Dominator
Make: SR5.4
Length: 7m +
Engine: Yam 85
MMSI: 235055163
Join Date: Jul 2005
Posts: 13,069
|
Personally I'd go for a 15hp and prop it right. At least that way waves hitting the bow won't stop you dead in your tracks. I prefer 1hp per metre up to 4m then 2hp/m and round up to next available size after that as a rule of thumb.
I'd have a bigger one for mine if I could fit it on the transom.
__________________
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
|
|
|
|
|
15 January 2007, 10:15
|
#6
|
|
Member
Country: UK - Channel Islands
Town: Guernsey
Boat name: Monkey Nutz
Make: Cougar R8 Sport
Length: 8m +
Engine: 350Sci Verado
Join Date: Aug 2006
Posts: 931
|
__________________
|
|
|
|
|
15 January 2007, 15:02
|
#7
|
|
Member
Country: Ireland
Town: Dublin & Enniscrone
Boat name: K'adó
Make: Redbay
Length: 7m +
Engine: Suzuki 300
Join Date: Oct 2004
Posts: 613
|
Yamaha High thrust
Tony
One of the problems I find wiht auxs is their ability to grip the water. For this reason I prefer the high thrust with the bigger prop and reduction gearbox.
Personally I took the aux off the boat on grounds
1 If weather really too bad I should not be out on my own.
2 If weather ok I should be able to anchor until help arrives
Above assumes i is keeping an eye on forecast and radio is working.
Rgds
__________________
Take it easy ....but, take it all the way.
|
|
|
|
|
16 January 2007, 00:18
|
#8
|
|
RIBnet admin team
Country: UK - England
Town: The wilds of Wiltshire
Boat name: Dominator
Make: SR5.4
Length: 7m +
Engine: Yam 85
MMSI: 235055163
Join Date: Jul 2005
Posts: 13,069
|
Quote:
Originally Posted by Ezgoing
Tony
One of the problems I find wiht auxs is their ability to grip the water. For this reason I prefer the high thrust with the bigger prop and reduction gearbox.
Personally I took the aux off the boat on grounds
1 If weather really too bad I should not be out on my own.
2 If weather ok I should be able to anchor until help arrives
Above assumes i is keeping an eye on forecast and radio is working.
Rgds
|
Calling the lifeboat out to tow you in is a bad thing to do if there's a safe way round it.
Do you guys have an equivalent of the RNLI in Eire?
__________________
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
|
|
|
|
|
16 January 2007, 00:45
|
#9
|
|
RIBnet admin team
Country: UK - Scotland
Boat name: imposter
Make: FunYak
Length: 3m +
Engine: Tohatsu 30HP
MMSI: 235089819
Join Date: Sep 2005
Posts: 11,627
|
Quote:
Originally Posted by Nos4r2
Do you guys have an equivalent of the RNLI in Eire?
|
RNLI covers S. Ireland too.
__________________
|
|
|
|
|
16 January 2007, 09:25
|
#10
|
|
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: 3,726
|
Quote:
Originally Posted by Nos4r2
Calling the lifeboat out to tow you in is a bad thing to do if there's a safe way round it.
Do you guys have an equivalent of the RNLI in Eire?
|
And if there isn't a lifeboat you are really in deep s***! 
The only time I have needed my aux in anger was a few weeks ago and I was bloody glad I had it there and ready to go.
__________________
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
|
|
|
|
|
Posting Rules
|
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
HTML code is Off
|
|
|
|
Recent Discussions |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
White Noise
