AUX Outboard on a Rib

davis · 25 January 2007, 18:28

Do most people on here use an Aux outboard on their rib and what hp do they use, just that there doesnt seem to be much room beside the main engine, also a lot of the time I am in the company of other boats. The weight at the back is also a concern as my Aux is four stroke.

Biggles · 25 January 2007, 19:03

Don't have an auxiliery. Joined Sea Start instead. If your in company all the time then save your money. If not then its worth considering. However I can't imagine any Aux pushing a RIB any sort of decent distance, in anything other than calm seas.

Best of luck in your research.

PeterR · 25 January 2007, 19:28

I,ve only just got one after three years but it was always a worry till now.They say 1 hp per metre of boat.The weight i think will effect your top speed.

Aidan · 25 January 2007, 23:08

We dont have Rib start service or here (At least not on the west coast),its friggin whistle dixie or row!!!! (a spare set of batteries and a kind smile to RNLI helps, oh and I am a member of that for sure)....

Why in our day Boy!!! all we had was a currach and a set of lollipop sticks and we battled the atlantic WHat What! (sure you did you auld crone)
(Currach is Irish row boat of tarred canvas on wodden frame, huge bow rise for a few obvious reasons)

Nos4r2 · 25 January 2007, 23:46

I finally found one that fits on mine after changing to a wider engine(when I get it working properly

) Ancient 2hp Evinrude with a single clamp screw. On trying it out it made 3mph but should do a bit better when it's sorted out.

It's not big enough but it's enough to keep steerage way or get me to the nearest safe shore down tide in f4 or less. If it buys me some time in an emergency then it's worth having it.

What boat have you got?

Stoo · 26 January 2007, 00:13

Quote:

Originally Posted by davis

Do most people on here use an Aux outboard on their RIB...

I don't, but I've been thinking about for about 10 years! The truth is that I don't think I could really fit one in. I have some lovely paddles and a "cat-'o-nine-tails" though...

Is that "formula" of 1hp/metre generally accepted?

BogMonster · 26 January 2007, 08:34

I have because there is no lifeboat and no sea start in this part of the world!

There isn't much room and I had to lose the A frame to fit it in a position where there was any chance of turning it (my main engine is a V4 not a straight four so quite wide)

If you are in the company of other boats then its probably not worthwhile but I'm not, the prevailing wind is West and the next stop heading east is Chile again, 13,000 miles away... if I'm lucky I might wash up in S Africa which is only about 4000

MarkM · 26 January 2007, 09:04

I had a 5hp Honda 4-stroke. Carried around for years, sitting in the bow space. Used it once in winter time when nobody was out on the water. Reached 8km/hr. Took me hours to get to the habour over a distance of 8 kilometers, it's hard to use on a bigger boat. Now I've sold it because it's hardly any use and I don't have to carry that weight anymore.

I considred the following:
When I go out onto open sea, I'm always with another RIB.
When I stay near the coast I can call the coastguard's alarmnumber with the mobil phone.
On the inland waters are many people around.
I've an engine that has proved itself.
I carry two anchors and lots of rope.

I've to be cautious in winter time when nobody is out.

BogMonster · 26 January 2007, 09:31

Quote:

Originally Posted by MarkM

I had a 5hp Honda 4-stroke. Carried around for years, sitting in the bow space. Used it once in winter time when nobody was out on the water. Reached 8km/hr. Took me hours to get to the habour over a distance of a 8 kilometers, it's hard to use on a bigger boat. Now I've sold it because it's hardly any use and I don't have to carry that weight anymore.

I considred the following:
When I go out onto open sea, I'm always with another RIB.
When I stay near the coast I can call the coastguard's alarmnumber with the mobil phone.
On the inland waters are many people around.
I've an engine that has proved itself.
I carry two anchors and lots of rope.

I've to be cautious in winter time when nobody is out.

True but it is still much more embarrassing to have to call for help than to be able to sort your own problem out

You have to sit in an awkward position to use mine, but I quickly discovered that if you set it to a particular angle (just off centre) and tweak up the friction on the tiller, you can leave it chugging away, trim the main engine right down and steer with that, which is a lot easier, the turning circle is a bit indecent but it works.

Mine (6hp Johnson 4 stroke) does about 5 knots or so on the 5.8 Humbug but it isn't reaching anywhere near full revs so I might improve on that with a finer prop if I can get one.

MarkM · 26 January 2007, 09:35

@BogMonster: I agree with you. But your situation in completly different from mine. Here the waters are usely crowed with boats.

Nos4r2 · 26 January 2007, 09:45

I'm looking at all these reasons why not to and thinking has anyone heard of the 'Incident Pit'?

Best not to get yourself in the situation to start with-but if you do then make damn sure you've got a way out.

We had main engine problems just outside the entrance of Poole Harbour on a rising spring tide a couple of years ago just as every man and his dog including the truck ferry came back in. Had we not had an auxiliary we would have been in deep sh*t and calling mayday.

Lawrence · 26 January 2007, 10:17

Quote:

Originally Posted by BogMonster

True but it is still much more embarrassing to have to call for help than to be able to sort your own problem out

I always carry an auxiliary, a Johnson 4 converted to a 5hp. I prefer having the peace of mind and not being dependent on others -
apart from the safety considerations.
The only time I went out in my old Sea Ray without an auxiliary it broke down and I was left bobbing around in the swell for an hour just off Trefusis Point

; loads of boats passed by before some likely lads in "Two Hoots" towed me in. If I'd had my auxiliary I'd have been back into Falmouth in 10 mins. Instead it was embarrassing waving pathetically at passing boats "Please rescue me...."

BogMonster · 26 January 2007, 14:13

Quote:

Originally Posted by MarkM

@BogMonster: I agree with you. But your situation in completly different from mine. Here the waters are usely crowed with boats.

True but regardless of that I'd still rather have a spade to dig myself out of the sh*t than stand there in me wellies looking helpless. Even if it is only a small spade which doesn't dig very fast

The only time I have needed mine (which I know was partly my own stupid fault) I would not have had time to be rescued as I was drifting in to shore at an alarming rate and only just got the aux going in time to avoid a probably terminal meeting with either a rocky beach or an old (and very jagged) shipwreck. Paid for itself at that moment and now doesn't owe me anything

shthpnz · 08 February 2007, 21:40

I always carry an aux motor with me in one of the storage places of my rib. On the wetlands above Holland and Germany or around Greece in the summer. Knowing I am not dependent on the main motor alone gives me a secure feeling.

Tohatsu 9.8 hp. Used it only once when the main motor stopped miles from anywhere in the south of the Pelopennesos-Greece. No oil pressure left. The Tohatsu came in handy. Difficult to find an easy way to steer the ship though. But after some hours I proudly steamed into a harbour. But the failure ended the boating fun that summer.

Roel

mike · 10 February 2007, 22:24

It's true that a small engine will struggle to make a boat go anywhere near well in a larger sea however I work on a self sufficiency basis, aux = 15hp
oars 4 vhfs flares epirb 2x gps etc etc the aim is get myself out of trouble if I can.
on the 1 occasion we lost the main engine it was in the middle of a busy shipping lane.

coastguard called we trundled out of the way on a 3.3 merc. we then ran 13 miles back without problem sea start would not have helped we would have been toast

, so I do feel it is always worth having an aux.

The other I noted was that most of the time the prevailing conditions are good on the days we go out and so most of the time the aux is fine.

definately get one

JABS · 12 February 2007, 09:09

Don't forget that one of the frequent causes of loss of engine power is fuel related.

It can range from contamination, made worse by the action of a RIB in a rough sea, to fuel starvation caused by problems on the supply system.

Why not consider a back up to the fuel source and delivery system as well as a back up engine.

If both engines use the same type of fuel and each can be fed from either fuel systems, all eventualities are eliminated.

We have 90 and six HP Mercury four strokes, the inboard tank as well as an auxilliary tank and an adaptor to enable the 90 to run off the aux tank!

Weight penalty, massive. Confidence factor also massive!

BruceB · 24 April 2007, 00:07

I use a 2.3hp 4 stroke Aux mounted on the transom and strapped down with a ratchet strap. I also have two independent tanks that are set up to plug/feed either motor without tools in a few seconds, one 70L and one 12L.
I like getting out of bother by myself as i operate up and down the west coast diving and it can be remote, plus not picking up the divers can be a bit dodgy!
I did break down once just outside Oban when my aux had chucked it a few trips before and it 1.5hrs of paddling the boat to shore, no boats around which would have meant the lifeboat. I wasn't calling that out just to save a bit of a paddle when we were in no danger.
Neddless to say I went out and bought another before the next trip!
Oh, and on a 5.3m RIB I get 4.5knts with the leg down to steer on a 2.3HP aux.

jwalker · 24 April 2007, 00:27

Quote:

Originally Posted by Biggles

.. However I can't imagine any Aux pushing a RIB any sort of decent distance, in anything other than calm seas.

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

Jon.esp · 24 April 2007, 20:51

I have only recently bought a Rib having previously been Bluewater cruising.
We keep the boat in Spain and even though there are usually other boats in sight I wouldn’t like the idea of not being able to get myself out of any mess I got myself into.

We have a 6hp Yamaha 2 stroke as an Aux which just fits on the transom. I like JABS idea of having interchangeable fuel tanks but for me that would men a 4 stroke Aux which is bigger and wouldn’t fit Mind you with a two stroke being Oilyer and less complicated I suspect it is more likely to cope with he abuse and neglect it will no doubt have to put up with.

The problem I have come up with is that the Tiller of the Aux fouls the A Frame and makes it very difficult to steer with.

I reckon I have a number of options but would welcome any comments or ideas.

a. fit the Aux on a bracket that extends it aft by 12 inches or so. This would then allow the tiller to clear he A Frame but then would b too far to reach and steer with!!!!!!

b. Fit a tie rod to the main engine steering ad have a remote throttle control. This sounds complicated and the geometry of the tie rod my cause problems.

c. Fit at temporary tiller to the handle where the remote steering cables would attach. The existing tiller could be held in the vertical position for the throttle.

d. Use the main engine as a rudder. Bruce B seem to do this and as I would love to know how successful it is?

Any Ideas????

BogMonster · 24 April 2007, 21:02

Quote:

Originally Posted by Jon.esp

d. Use the main engine as a rudder. Bruce B seem to do this and as I would love to know how successful it is?

Any Ideas????

Works fine, gives the turning circle of a supertanker on my Humber (well slight exaggeration, probably about 100-150m turning circle) so I wouldn't like to try it in busy conditions but works OK and a lot less tiring in the cruise (if you can call 4kt a cruise!).

I am still running in the aux engine plus if it is a nice day and I am not in a hurry I run it for 15-20 min just toddling along at half throttle or so to give it a good run (good for the engine to do this and makes it easier to start in a hurry if done regularly!) and unless I am messing around with dolphins or something, I always use the main engine as a rudder.

Because of the offset position you usually need to offset the aux tiller very slightly (about 5 - 10 degrees) to straighten up the boat and even then it "crabs" very slightly but that is not related to using the main engine, just the position on mine.

I binned my A frame because it meant no steering at all.