Reply
 
Thread Tools Search this Thread
 
Old 17 May 2013, 05:07   #1
Member
 
Country: Other
Town: Hole Town
Boat name: Tiny Dancer
Make: AB Inflatables
Length: 4m +
Engine: Mercury 40 hp, 4 str
Join Date: May 2013
Posts: 3
What speed for my new RIB?

Hello all,
Frist time post Ė Just bought an ĎAB Inflatables 13 foot RIB (VS13) and a Mercury 40hp EFI 4 stroke. Iíve not had a go in it yet as Iím waiting for the small center console, wheel, and controls to be fitted.
As you can imagine, Iím bursting to get it in the water. I keep it in Barbados and it will be used just for leisure and hopping between the beach bars on the west coast. Up until now I have been hiring a slightly smaller (12 foot) AB rib fitted with a 25hp motor. I wonít be back in Barbados until late June, but by then my Rib will be ready to use.
No doubt Iíll be posting questions to pick the brains of the more experienced forum members over the next couple of weeks, but Iíll get the dumbest one out of the way nowÖ How fast (very roughly) do you think it will go (flat out / and practical cruising)
Cheers
Colin
__________________

__________________
Colin Barbados is offline   Reply With Quote
Old 27 May 2013, 03:57   #2
Member
 
Exe treme's Avatar
 
Country: UK - England
Town: Exeter
Make: Highfield
Length: 5m +
Engine: Honda BF90
Join Date: Mar 2013
Posts: 272
Wow. Thats a lot of power and weight for a 13 ft rib, but there are others that can handle the same and I believe AB make good ribs. There are lots of considerations like prop pitch, max hull design speed, boat weight etc, etc, which is possibly why you haven't had any response. A friend of mine has a similar size with a Tohatsu 40 2-st but he gets scared at 27 mph, so not sure of w.o.t speed. Expect easy cruising at 20-25 mph and w.o.t. in excess of 30-35 mph if set up correctly, and if you are brave enough as it might feel like it is going to take off! I am no expert but thought I would respond as nothing else has been posted.
__________________

__________________
Happy when wet!
Exe treme is offline   Reply With Quote
Old 27 May 2013, 05:04   #3
Member
 
Country: Other
Town: Hole Town
Boat name: Tiny Dancer
Make: AB Inflatables
Length: 4m +
Engine: Mercury 40 hp, 4 str
Join Date: May 2013
Posts: 3
Quote:
Originally Posted by Exe treme View Post
Wow. Thats a lot of power and weight for a 13 ft rib, but there are others that can handle the same and I believe AB make good ribs. There are lots of considerations like prop pitch, max hull design speed, boat weight etc, etc, which is possibly why you haven't had any response. A friend of mine has a similar size with a Tohatsu 40 2-st but he gets scared at 27 mph, so not sure of w.o.t speed. Expect easy cruising at 20-25 mph and w.o.t. in excess of 30-35 mph if set up correctly, and if you are brave enough as it might feel like it is going to take off! I am no expert but thought I would respond as nothing else has been posted.
Many thanks for the reply Exe,
That will give me a starting point. I donít know the pitch of the prop yet. The dealership who have sold me the engine have visited the boat in order to choose the best pitch for its size and shape. I agree a 40hp 4 stoke is a big lump for a tiny rib, but the very similar rib Iíve been hiring up to now had a 25hp attached and left me thinking Iíd like just a bit more. A 30hp was considered, but at only 5 more horses seemed too small an increase. Buying a brand new outboard is a big investment for me and I didnít want to commit to a 30hp and soon be wishing Iíd got for the 40.
The plate on the RIB says 40hp max and the weight is within spec. The Rib seems very workman like and strongly built. The 13Ē VS AB Rib (Navigo range) does not come as standard with a factory fitted center console, but is an open tender with a tiller grip outboard. The console will move my weight more forward and will help the balance fore and aft.
Iíve noticed that a lot of the posters tend to speak about MPH instead of knots, is this a RIB thing?
A cruising speed of 15 to 18 knots will be just perfect and anything approaching 27 knots WOT would be fine to put a bit of wind through my non-existent hair. I have many years of experience driving much more powerful small craftÖ workboats and fast rescue craft in the off-shore industry, but they have all been jets, I know diddly squat about low powered props. Lots more dumb questions to follow.
Cheers
Colin
__________________
Colin Barbados is offline   Reply With Quote
Old 27 May 2013, 05:24   #4
RIBnet admin team
 
Poly's Avatar
 
Country: UK - Scotland
Boat name: imposter
Make: FunYak
Length: 3m +
Engine: 2 stroke YAM 20 HP
MMSI: 235089819
Join Date: Sep 2005
Posts: 10,114
Possibly fast enough to scare the **** out of most people who might be driving it! I get 22 knots out of a similar sized boat with a 20HP 2str and it feels like driving a go-cart. I'd take it easy to start with and make sure you have a life jacket and kill cord on. If it starts chine walking it could flip you out!
__________________
Poly is offline   Reply With Quote
Old 27 May 2013, 10:09   #5
Member
 
Country: UK - Scotland
Boat name: Wildheart
Make: Humber/Delta Seasafe
Length: 5m +
Engine: Merc 60 Clamshell
MMSI: 235068449
Join Date: Apr 2007
Posts: 4,610
Colin,

Hi, your post must have been eclipesd by one I had seen already. Welcome to the madhouse!

Cruising wise most ribs of that size seem to go "nicely" with best fuel effy between 20- 25 knots. FWIW I have a 60HP on a 5m (16') and the difference between 22 & 28 knots is quite a step change in concentration & hard work.

Sounds like you might have a bit of fun with that!
__________________
9D280 is offline   Reply With Quote
Old 29 May 2013, 05:44   #6
Member
 
Country: Other
Town: Hole Town
Boat name: Tiny Dancer
Make: AB Inflatables
Length: 4m +
Engine: Mercury 40 hp, 4 str
Join Date: May 2013
Posts: 3
Quote:
Originally Posted by 9D280 View Post
Colin,

Hi, your post must have been eclipesd by one I had seen already. Welcome to the madhouse!

Cruising wise most ribs of that size seem to go "nicely" with best fuel effy between 20- 25 knots. FWIW I have a 60HP on a 5m (16') and the difference between 22 & 28 knots is quite a step change in concentration & hard work.

Sounds like you might have a bit of fun with that!

Poly, Many thanks for the advice; a kill cord is a given. Iíll certainly be taking it steady until I get a feel for how this particular combination of boat / engine reacts to the sea state.
9D280, Thanks for the welcome. ďNicelyĒ at 20 Ė 25 knots would be perfect. Fuel efficiency may be important. There is a fuel dock a couple of hundred meters for where I keep her at Port St Charles, most of the destination beaches are between 2 and 8 miles run (one way) from there.
I would like to be able to get to Bridgetown and back (with a comfortable reserve in hand) Bridgetown would be a 28 mile round trip. Does that sound doable on a single tank? Iím assuming the tank that arrives with the engine will be 22 ltr.
Any thoughtsÖ
__________________
Colin Barbados is offline   Reply With Quote
Old 30 May 2013, 10:16   #7
Member
 
Country: UK - Scotland
Boat name: Wildheart
Make: Humber/Delta Seasafe
Length: 5m +
Engine: Merc 60 Clamshell
MMSI: 235068449
Join Date: Apr 2007
Posts: 4,610
As a going in guess and until you get some "hard data" (even if you stick a handheld GPS in your pocket!), assume 1L/ mile. Onthe first few trips it's worth making regular checks of the tank (like pick it up or look in the filler - don't rely on those useless built in fuel guages!).

I've kept a note of fuel / dist / sea state / driving style data since I rebuilt my engine, and so I am now a lot more confident about predicting useage knowing the planned activity / weather forecast.

Portable tanks are cheap. It's prrobably worth buying another and using them turn about (stops the fuel in #2 going stale). Also means if for some reason you get water in one, you can swap & get back.
__________________

__________________
9D280 is offline   Reply With Quote
Reply

Tags
rib

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 08:36.


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