AUX Outboard on a Rib - Page 2

Jon.esp · 24 April 2007, 21:15

Thanks Stephen Thats interesting

Can you steer it at all with any sea running or is that a lost cause

where we are a F5 sea breeze with a chop is the norm. coming into a narow harbour enternace could be interesting.

BogMonster · 25 April 2007, 11:39

Quote:

Originally Posted by Jon.esp

Thanks Stephen Thats interesting

Can you steer it at all with any sea running or is that a lost cause

where we are a F5 sea breeze with a chop is the norm. coming into a narow harbour enternace could be interesting.

To be honest I haven't tried with any kind of a sea running - but I think it would be difficult. To offset any tendency to turn with the sea I would think the best answer would be to offset the tiller on the aux a bit more so it is tending to turn you back in to the sea, until your main engine is about in the straight ahead position for steering. Just my theory though - I haven't tried that! However I think it would work as the reason I run with my aux thrusting slightly to port is because I discovered I had lots of steering in one direction and bugger all in the other so I adjusted it till the boat was running more or less straight and I had reasonable steering in both directions.

The other reason I prefer to use the main engine as a rudder is that my boat is an awful lot wetter sitting on the tube at the blunt end than where I normally sit

Pete7 · 25 April 2007, 18:26

Quote:

Originally Posted by jwalker

Biggles, are you not familiar with Chris Kay's aborted Iceland trip?

Oh yes about 90 hours steaming on a single aux engine across the North Atlantic to get home

BruceB · 25 April 2007, 18:59

I have mine mounted on a cut down and narrowed outboard bracket about 6 inches behind the transom. It means it clears the A Frame.
I used to have a small 2 stroke 3.5 and despite buying it new a year later it was gubbed. I didn't run it much because flushing it was a problem and fuel had to be premixed which was a problem for storage. It was found the first time it needed to be used for real that it was knackered!
I have since bought a 2.3hp 4 stroke Honda which is air cooled. Fuel is now no problem and I run it every trip cos it doesn't need flushing.
It seems to steer OK using the main leg apart from the above mentioned large turning circle. I haven't tried it in rough weather yet but it doesn't need to be perfect, just get me home......

G L · 25 April 2007, 22:07

If you have a aux fitted, make sure your mate dosen't drop it the sea when he takes the boat out?

vince · 26 April 2007, 10:54

At least i dont crash into the back of my car when trying to put the rib on the trailer! Yes folks, GL nearly went through the back of his frontera!!

IBWET · 26 April 2007, 15:45

Looks like you need to update your pers details....

Quote:

Originally Posted by vince

At least i dont crash into the back of my car when trying to put the rib on the trailer! Yes folks, GL nearly went through the back of his frontera!!

G L · 26 April 2007, 17:13

Thats the one of best thing about ribs, they bounce of things!!!

Jon.esp · 26 April 2007, 19:26

on a more serious note

has anybody changed their prop on the Aux.
I was just thinking about it. If I have a 6hp aux it will never get on the plane so there must be huge slipage or the engine will never reach optimum revs.
I also have an 8hp short shaft on an Avon 2.8 rib which we used as a tender and that gets up on the plane with 2 or enen 3 up.
What props do these sailing boats have on their auxilary outboards? they dont plane.

codprawn · 27 April 2007, 01:12

Quote:

Originally Posted by Jon.esp

on a more serious note

has anybody changed their prop on the Aux.
I was just thinking about it. If I have a 6hp aux it will never get on the plane so there must be huge slipage or the engine will never reach optimum revs.
I also have an 8hp short shaft on an Avon 2.8 rib which we used as a tender and that gets up on the plane with 2 or enen 3 up.
What props do these sailing boats have on their auxilary outboards? they dont plane.

Very valid point - often they have high thrust 4 blade props - bigger diameter for more thrust at lower speeds. Having said that some of the outboards are also available with different gear ratios as well but they don't all offer that.

iainmartins · 02 May 2007, 15:48

i have been given an 2.5hp aux for my 6m humber do you think that i woukld even move it? considering it has a 200kg engine a 90l fuel tank seating for 3 and 1 standing. would be greatfull for your opinion?

BogMonster · 03 May 2007, 11:40

depends on the conditions I guess

you can paddle a RIB in ideal conditions (no sea and no wind) but you won't get far going in to a headwind

BruceB · 03 May 2007, 13:02

I would probably think it was a bit small to get any real movement but as you have it already then ask the question on is it betetr than paddling.....
I bet a 2.5hp outboard can move a 6m rib better and faster than paddling, even in calm conditions......

Mugshot · 03 May 2007, 14:18

My 5.1m has a 2.5hp, and I've tried it in a very strong head wind, up river though so I wasnt trying to tackle any waves of any consequence, it wasnt much cop to be honest, it was difficult to steer as the wind took you and I made very little real progress, HOWEVER, I believe that if need be it would keep me off rocks and at the very least hold my position 'til help arrived if I needed it and I'd rather do that with an engine than a paddle

BogMonster · 04 May 2007, 11:39

Quote:

Originally Posted by Mugshot

it wasnt much cop to be honest, it was difficult to steer as the wind took you and I made very little real progress, HOWEVER, I believe that if need be it would keep me off rocks and at the very least hold my position 'til help arrived if I needed it and I'd rather do that with an engine than a paddle

much the same could be said of my 6hp though - a 20kt crosswind makes the thing nigh on impossible to steer in any sort of sensible direction!

You tend to forget how much a RIB weighs till you try and manoevre it with a strimmer engine

chris p · 06 May 2007, 08:08

i have a humber 6.3 inboard with a yamaha 4hp 4 stroke on the back. The boat will move at 4kn no wind no tide, but only 1.5 /2 kn with 2kn tide no wind. the turning circle is brilliant (on a sixpence) with leg up. Had to use it for real a cupple of weeks ago as water hose went on engin, yam started 2nd or 3rd pull after 3months no use but fuel in auxilery tank was was going off so kept cutting out, changed fuel now works ok

Tims Osprey · 15 May 2007, 20:53

i shouldn't have that problem because i'm buying a rib with twin 60 mariners on the back

Biggles · 15 May 2007, 21:28

Quote:

Originally Posted by Tims Osprey

i shouldn't have that problem because i'm buying a rib with twin 60 mariners on the back

But if you want to be extra safe have you ever thought both of your engines might pack up then you'll need an auxiliery !

vince · 16 May 2007, 04:54

Especialy if its the fuel to blame and both engines feed off one tank. Thats why we run the aux off a seperate 25l just in case.

bedajim · 16 May 2007, 07:08

Quote:

Originally Posted by Tims Osprey

i shouldn't have that problem because i'm buying a rib with twin 60 mariners on the back

Does it have twin fuel tanks,twin batteries etc?