Aux on a 5.4m

JSP · 30 November 2008, 09:29

What's the smallest sized motor for an Aux on a 5.4m hull?
I have a 2.5hp mercury but I'm guessing I could do with around 4-6hp?
The 2.5 merc only has an inboard fuel tank which is a pain as I'd like the option to run of main tanks.

Poly · 30 November 2008, 09:39

JSP - I have moved boats that are 6.5m with a 2HP engine quite comfortably (in fact a 5m+ boat once towed my sailing dinghy with a 2HP engine) - but in anything but calm conditions with minimal tide you won't make much if any progress. Perceived wisdom on here is that 1HP per m of hull length is about right for an aux. Not sure how much space there is on the transom of your 5.4 - but that may limit your options somewhat.

In terms of fuel tank - running off the main tank is a nice option - but bear in mind that a lot of engine problems are fuel related so in terms of redundancy it is desirable to have a separate tank etc. for the aux.

PeterR · 30 November 2008, 10:29

I would have said if you have a flooding hull it wont preform as well as one on a sealed hull

Nos4r2 · 30 November 2008, 10:49

You probably won't have room for any bigger than the 2.5hp merc on a 5.4 if you want an A-frame without fitting an aux bracket. I can only just get my DT2.2 on mine. It'll do 4 knots max with the 2.2-better than nothing but not ideal.

I have a fuel connector on a bit of hose so I can refuel my aux from the main tank by pumping the primer bulb.

spartacus · 30 November 2008, 11:16

I managed to squeeze a Tohatsu 3.5hp (2-stroke) on my Zodiac 7 man Pro (4.20m). It's available as a 4hp (4-stroke), but was just too wide for my particualr set-up. Older versions of the Yamaha 4hp 2-stroke do come up now and again but they're like hen's teeth.

Nos4r2 · 30 November 2008, 11:27

Quote:

Originally Posted by spartacus

I managed to squeeze a Tohatsu 3.5hp (2-stroke) on my Zodiac 7 man Pro (4.20m). It's available as a 4hp (4-stroke), but was just too wide for my particualr set-up. Older versions of the Yamaha 4hp 2-stroke do come up now and again but they're like hen's teeth.

There's even less room on a 5.4.
Here's a (badly blown up) pic of mine with the DT2.2 on it-they were just touching when both are tilted and about 2mm clearance at full lock when the main engine is down.
Of course, you could fit a 4-6hp if you don't have an A-frame.

JSP · 30 November 2008, 12:14

Thanks for the info everyone. I may try and get away with my 2.5 then. It's a cracking little engine. I like your idea of having a pipe to fill from the main tanks Nos.
The Aframe on yours is fixed on the outside of the transom isn't it Nos? I'm thinking of fitting a twin tubed to the deck. So, I would have more room BUT I think I'd be tw*ting the Aframe with the tiller arm. One to think about.

Nos4r2 · 30 November 2008, 12:21

Quote:

Originally Posted by JSP

Thanks for the info everyone. I may try and get away with my 2.5 then. It's a cracking little engine. I like your idea of having a pipe to fill from the main tanks Nos.

It works quite well. I'm thinking of putting a T-piece into the fuel line on the aux and fittingthe fuel connector to that so I can pump fuel straight up into the tank without having to open the filler cap next.

Quote:

Originally Posted by JSP

The Aframe on yours is fixed on the outside of the transom isn't it Nos? I'm thinking of fitting a twin tubed to the deck. So, I would have more room BUT I think I'd be tw*ting the Aframe with the tiller arm. One to think about.

Your aux will protrude into the boat anyway so having the A-frame either side of the transom won't make much difference. You still need to be able to do the transom clamps up.

JSP · 30 November 2008, 12:34

Bugger it I'll buy paddles

Nos4r2 · 30 November 2008, 12:38

Quote:

Originally Posted by JSP

Bugger it I'll buy paddles

You could always do what Bedajim did on his sr4 and make an A-frame that the aux attaches to.

JSP · 30 November 2008, 12:42

Quote:

Originally Posted by Nos4r2

You could always do what Bedajim did on his sr4 and make an A-frame that the aux attaches to.

And look it off straight and use the main motor for steering?
Sticking two large paddle wheels on the side coupled to and exercise bike fitted onto the jockey, renaming the boat Mississippi is another option. Cardiac arrest anyone?

Nos4r2 · 30 November 2008, 12:58

Quote:

Originally Posted by JSP

And look it off straight and use the main motor for steering?
Sticking two large paddle wheels on the side coupled to and exercise bike fitted onto the jockey, renaming the boat Mississippi is another option. Cardiac arrest anyone?

Probably better to ask Bedajim how he did it.

JSP · 30 November 2008, 13:03

Always taking the easy way out Nos

I will do, cheers mate

towersje · 01 December 2008, 01:05

One thing worth mentioning, if I'm carrying an aux I'll generally have a tank to go with it too. Say your main fuel is contaminated, or your fuel hose is damaged, then with a backup tank you'll still be able to get home

True it's more space, but worth it in my opinion!

And 2.5 should be more than enough. It won't get you on the plane

but it will get you there eventually!

Quote:

Bugger it I'll buy paddles

5.4s paddle quite nicely off the front, a good technique if trying to talk to and follow wayfarers round in very little/nae wind

JSP · 02 December 2008, 16:03

Cheers for the advice Tower