Reply
 
Thread Tools Search this Thread
 
Old 19 January 2011, 19:06   #1
Member
 
richardjawilson's Avatar
 
Country: UK - England
Town: Boat Lake Geneva
Boat name: Lark
Make: Capelli Cap 32 WA
Length: 10m +
Engine: Yamaha 250x2
MMSI: 235096621
Join Date: Feb 2006
Posts: 193
What hp needed to power a 2.7m RIB?

Hi there, I have a 2.7m rib tender, used to access the bigger rib when its on a swinging mooring on the Dart.

The tender is a Tidalwave one, cheap but does the job, boat only weight is about 55 kgs, rated to 9.9hp with payload inc motor of about 315kgs, so 3 adults.

Its currently/temporarily powered by a 4hp 2 stroke Mariner Sailmate but that's a longshaft and has a prop for suited to heavier boat. It digs the stern in when underway and with 2 up, it can't overcome the extra drag of the leg so does not plane (4hp with 2 up may not be enough anyway to make it plane even with an s/shaft).

I am thinking of a S/shaft 6hp or a 9.9hp, but I am concerned about the weight of the 9.9 over the 6. The 8 hp's seem to weigh the same as 9.9's, so I've ruled that engine size out.

Any thoughts??


Thanks Richard

ps,

Budget not too much of an issue.
The new or s/hand engine may also double as aux on a 6m rib.
More than happy with a 2 or 4 stroke but favouring 4.
__________________
richardjawilson is offline   Reply With Quote
Old 19 January 2011, 19:24   #2
Member
 
Country: Canada
Town: Quebec city
Make: Zodiac hurricane
Length: 7m +
Engine: Yamaha
Join Date: Dec 2008
Posts: 106
outboard

First thing do not try to raise the transom to use a long shaft outboard on a short shaft application. I've tried it before on a 3,10m RIB and I almost flipped the boat the first time I floored it, very dangerous.

With a short shaft 4 hp you should be able to plane (in calm water) by distributing the weight in the boat, however I don't know the brand & model of your boat so it might not be true. On a Cadet RIB 260 with a 4 stroke Yamaha I got it to plane real easy.

My suggestion is to get a Yamaha 2 stroke 8hp short shaft. I don't know if 2 strokes are still available in UK but here in Canada this model is very popular. The Yamaha 2 stroke 8hp weights only 60 pounds, wich is the same as the 4 stroke 4hp and 6hp.

With a 8hp, you'll not only plane in an instant but it will be a reasonnable auxiliary for your bigger RIB.

Cheers!
__________________
Boulet Lemelin Yacht inc.
1125 boul. Champlain
Québec QC G1K 0A2 Canada
educhesne@blyacht.com
achille2124 is offline   Reply With Quote
Old 19 January 2011, 22:04   #3
RIBnet admin team
 
willk's Avatar
 
Country: Ireland
Length: 4m +
Join Date: Feb 2008
Posts: 14,904
Intestesting. I asked this question here recently for my 2.7 air deck. The answer was basically the Yammie 8hp 2T or a Tohatsu 9.8hp 2T. They weigh much the same at 26kg ONO.

I went Tohatsu and the trial run was more fun than a barrel of monkeys.

__________________
willk is offline   Reply With Quote
Old 20 January 2011, 09:05   #4
Member
 
richardjawilson's Avatar
 
Country: UK - England
Town: Boat Lake Geneva
Boat name: Lark
Make: Capelli Cap 32 WA
Length: 10m +
Engine: Yamaha 250x2
MMSI: 235096621
Join Date: Feb 2006
Posts: 193
9.8 Tohatsu sounds great but where can I buy one? I guess I need to wait for one the crop up on ebay etc.
__________________
richardjawilson is offline   Reply With Quote
Old 20 January 2011, 09:20   #5
RIBnet admin team
 
willk's Avatar
 
Country: Ireland
Length: 4m +
Join Date: Feb 2008
Posts: 14,904
They crop up now and then. I've seen three since September. They're not getting any cheaper, or younger!

Clicky
__________________
willk is offline   Reply With Quote
Old 20 January 2011, 12:09   #6
Member
 
Country: UK - Scotland
Boat name: Wildheart
Make: Humber/Delta Seasafe
Length: 5m +
Engine: Merc 60 Clamshell
MMSI: 235068449
Join Date: Apr 2007
Posts: 4,671
Or get a cheap & cheerful 2/4 Hp short shaft & bring the rib back to the pier / slip to pick the rest of the crew up?
__________________
9D280 is offline   Reply With Quote
Old 20 January 2011, 17:59   #7
Member
 
richardjawilson's Avatar
 
Country: UK - England
Town: Boat Lake Geneva
Boat name: Lark
Make: Capelli Cap 32 WA
Length: 10m +
Engine: Yamaha 250x2
MMSI: 235096621
Join Date: Feb 2006
Posts: 193
4/6 hp would work. I was looking at a new Yamaha 6 hp which would be great but the tohatsu 2 stroke is the same weight so would by that if I could.

Oh well I'm bid here for a tohatsu if anyone has anything.
__________________
richardjawilson is offline   Reply With Quote
Old 22 January 2011, 09:42   #8
Member
 
spartacus's Avatar
 
Country: UK - Scotland
Town: Aberdeenshire
Boat name: Sula
Make: Ribcraft 4.8m
Length: 4m +
Engine: Tohatsu 70hp + aux
MMSI: 235087213
Join Date: Jun 2007
Posts: 4,650
RIBase
Quote:
Originally Posted by richardjawilson View Post
4/6 hp would work. I was looking at a new Yamaha 6 hp which would be great but the tohatsu 2 stroke is the same weight so would by that if I could.

Oh well I'm bid here for a tohatsu if anyone has anything.
As luck would have it. (I don't know seller).
http://www.findafishingboat.com/tohatsu-9-8/DS29575
__________________
spartacus is offline   Reply With Quote
Old 23 January 2011, 10:24   #9
Member
 
spartacus's Avatar
 
Country: UK - Scotland
Town: Aberdeenshire
Boat name: Sula
Make: Ribcraft 4.8m
Length: 4m +
Engine: Tohatsu 70hp + aux
MMSI: 235087213
Join Date: Jun 2007
Posts: 4,650
RIBase
A few hours to go. Looks mint.

http://cgi.ebay.co.uk/tohatsu-9-8-hp...#ht_572wt_1141
__________________
spartacus is offline   Reply With Quote
Old 23 January 2011, 11:38   #10
Member
 
richardjawilson's Avatar
 
Country: UK - England
Town: Boat Lake Geneva
Boat name: Lark
Make: Capelli Cap 32 WA
Length: 10m +
Engine: Yamaha 250x2
MMSI: 235096621
Join Date: Feb 2006
Posts: 193
have seen that one, but its a 4 stroke. Good value though, but heavy at 37 kgs. I am tempted but its the weight thing.
__________________
richardjawilson 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




All times are GMT. The time now is 04:58.


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