A bit tight on the transom

[BogMonster]

Not really sure if this should be in the engine section or not as its a sort of engine problem but really a boat problem as well....

My new 6hp aux finally arrived yesterday (ordered in early June!) so I had a quick fiddle last night. No photos because it's dark so I have attached a photo of the boat from a while back ... but the aux barely fits on the transom alongside the other one, never mind being able to get much steering input (about 30deg one way and about 5deg the other before it hits either the A frame or the main engine cowling, and I haven't even tried steering with the main engine yet, it may be impossible with the aux fitted).

The only way I can see of making it work would be to lose the A frame completely - it couldn't go much closer to the tubes. The 4/5/6hp engines are all the same size and any smaller engine would be a waste of time (the 2.3hp is probably physically smaller but I might as well carry a set of paddles).

As far as I can see the Humber seems to be a fairly common size of RIB (not unusually narrow or anything). So those of you that carry aux engines - what do you do, lose the A frame? It means nowhere to put lights, nor anywhere for the VHF aerial, neither of which I want to do...

Any "light bulb comes on above head" ideas, preferably with photos would be gratefully received! Otherwise there's going to be a brand new aux engine for sale because if it hardly fits and won't steer then there's not much point in having one...

Thanks

Stephen

[fishbait]

fwiw I regularly go long distance/offshore in my ribcraft 585 and I carry a spare yamaha 8hp when I do. It is mounted onto the stern (g-clamps only), kicked up and the leg lashed to the a-frame to keep it secure. I don't have a problem with the mariner 90 engine's turning arc.

I appreciate that these arrangements inevitably come down to centimetres afa clearance etc is concerned. It's possible that with a bit of faffing you'll get the new aux to sit adequately?

Sorry not to be of any real help.

FS

[fishbait]

a bit drastic but perhaps you bond padeyes/strongPoints onto the deck to lash the engine to until you need it?

I'll give up now :-/

[Searider]

oops

[Searider]

Looks like your main engine is quite wide - is it a Vee engine?
A frame seems to taper inwards shortly after it gets above the top of the transom.
So, looks quite tight.

Three things spring to mind.

1. Will the clearance be improved if you mount the A frame on the inside of the transom, not the outside?

2. If not, you might have to mount the engine on an auxiliary bracket.

3. Is the clearance any different with your main engine up as opposed to down?

[codprawn]

Use a bracket to mount the engine further out. Also I have read somewhere you can just lock the aux straight and use the main engine as a rudder - haven't tried it myself yet though.

[Shaggy]

Hi
My Aux bracket is one that can be lowered into the water which allows it to move away from the A frame slightly, however there is little room to trun the tiller so it is a struggle but better than nothing

Something like this but not on a flappy thing



Shaggy

[Erin]

Originally Posted by codprawn

Also I have read somewhere you can just lock the aux straight and use the main engine as a rudder - haven't tried it myself yet though.

Yep, Codders is right. If you can fix the aux dead ahead you get quite good steerage from the main engine just acting as a rudder. The only problem is that small aux engines vibrate alot and no matter how tight you fix them they always start to turn. Somthing to do with poor balance on the crankshaft particularly on single cylinders.

Keith

[BogMonster]

Originally Posted by Searider

Looks like your main engine is quite wide - is it a Vee engine?
A frame seems to taper inwards shortly after it gets above the top of the transom.
So, looks quite tight.

Three things spring to mind.

1. Will the clearance be improved if you mount the A frame on the inside of the transom, not the outside?

2. If not, you might have to mount the engine on an auxiliary bracket.

3. Is the clearance any different with your main engine up as opposed to down?

Thanks for the replies.

I haven't had much of a fiddle yet because it was dark when I got home last night (winter!) but:

1. I don't think so

2. Might be one way round it, thanks

3. I think the aux tiller would then hit the main engine cowl but I must admit I didn't try it as it was dark and raining....

I looked through the RIB Raid photos for pictures of other boats but almost nobody seems to carry an aux....? So I guess the "best" option might be to lose the A frame... it then means finding some other location for nav lights and more importantly (I could live without nav lights) the VHF aerial which is essential for safety. For those who don't have A frames fitted, where do you put these? A "pole" (such as might be left if I sawed the A frame off two feet above the transom on one side ) would probably solve the VHF problem but it might look a bit odd. Are there any requirements for nav lights, in terms of where they should be located, height, spacing, location relative to each other etc etc?

Codders I was going to try the "main engine steering idea" so will post the result I suspect the steering may be "somewhat limited" but I don't see why it shouldn't work for longer trips, probably not for berthing though?

The other thing I need to check is whether the main engine is offset at all ... there might be an inch or so more room on the starboard side if so.

There was me thinking I could just clamp it on and go, why is nothing ever simple, bah humbug

[jwalker]

Stephen, without the A-frame there will be plenty of room. Here is a couple of pics as proof and the aux is a 30hp Mariner. Apologies for the lack of clarity, I've cropped them from bigger pics. There is a thread somewhere on ribnet describing how to connect both motors together for steering from the consol.