A bit tight on the transom

BogMonster · 23 August 2006, 10:59

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 · 23 August 2006, 11:48

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 · 23 August 2006, 11:51

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 · 23 August 2006, 11:52

oops

Searider · 23 August 2006, 11:55

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 · 23 August 2006, 12:04

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 · 23 August 2006, 12:13

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 · 23 August 2006, 13:25

Quote:

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 · 23 August 2006, 13:31

Quote:

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 · 23 August 2006, 14:08

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.

BogMonster · 23 August 2006, 15:41

Quote:

Originally Posted by 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.

Thanks.

I think the short term is going to see the existing A frame meet Mr A Grinder to leave a mast on the starboard side for the VHF aerial and will check if nav lights are compulsory but I don't think there are any regulations on a boat this size in this part of the world, that will get me mobile with the aux and a radio which are the main considerations.

I have got contact details for a guy who does all sorts of bespoke metalwork from one of the Land Rover forums I use, so I might get something different made up if it is a sensible price - it would only be a couple of hours work with the right tools and a bit of know-how, its just that I don't have either. A single hoop with a couple of fixing brackets welded on can't be too expensive ... all I want is something to stop the nav lights falling in the water

The next stupid question from this direction will be how to fill up the holes in the transom for a few months, but I'll go and do a search first because I'm sure it has been asked before...

Poly · 23 August 2006, 17:20

Quote:

Originally Posted by BogMonster

Thanks.

I think the short term is going to see the existing A frame meet Mr A Grinder to leave a mast on the starboard side for the VHF aerial and will check if nav lights are compulsory but I don't think there are any regulations on a boat this size in this part of the world, that will get me mobile with the aux and a radio which are the main considerations.

I have got contact details for a guy who does all sorts of bespoke metalwork from one of the Land Rover forums I use, so I might get something different made up if it is a sensible price - it would only be a couple of hours work with the right tools and a bit of know-how, its just that I don't have either. A single hoop with a couple of fixing brackets welded on can't be too expensive ... all I want is something to stop the nav lights falling in the water

The next stupid question from this direction will be how to fill up the holes in the transom for a few months, but I'll go and do a search first because I'm sure it has been asked before...

shouldn't be any regs on lights unless you are out at night. but you may regret disconnecting/removing them - surprisingly expensive for a light bulb and bit of coloured glass. especially with your long nights.

don't grind the frame yet - you'll be horrified at the cost of new one (never mind the shipping).

Could you just fit some spacers to move fwd/back an inch or two?

Does it stop you steering the main engine when its on or is it just you can't steer the aux.

mike · 23 August 2006, 18:02

I have had this problem before and got round it by having a plate fabricated which stood off the transom and had bracing plates on the inside of the boat, one of the A frame holes was used and a fraction bigger bolt then reinserted. The Engine when in situe effectively sat behind the A frame and the handle therefore was able to be positioned over the tube and not against the engine. Sorry no pix, hope you get the idea.

The engine was slightly turned over the tube as well

al40 · 23 August 2006, 18:57

I have similar issue with my 4hp aux hitting the tubes on 4m searider (fairly narrow transom and engine had to be jammed right against the tubes to allow main engine to turn full lock) but I was able to effectively tie it to prevent it moving - you'll find it will naturally want to move one way rather than the other (even when locked down hard) so you can usually tie against this.

Steering with the main engine works a treat once it's all balanced - you loose a little bit of speed (0.2 knts in my case) due to drag of main engine skeg but you can steer from the wheel which is much easier and also gets the weight forwards! You may be able to trim engine most of the way up (reducing drag) and still get enough steerage.

I had a short shaft aux so it wasn't close to the main engine in terms of depth clearance but on another engine with hydrofoils it was possible for the aux prop to hit the foils if main engine was turned - just something to look out for!

I'd also advocate not cutting the frame - really useful (and expensive!). If all else fails, a braket is a good solution. It also lifts the aux a bit higher out the way when not in use.

Limey Linda · 23 August 2006, 19:36

Hi Steven

Again, stop pissing about and get a bracket, that is what they are made for. You have tons of room for one. Asumming you are not mechanicaly challenged of course.

Have you got rid of that sausage shaped turd in the middle on your trailer yet and replaced it with rollers ?

BogMonster · 23 August 2006, 19:48

The existing A frame is a home made one made of black painted galvanised pipe so it isn't anything fancy or expensive to cut up.

I have details of a fabricator who will build just about anything but he doesn't specially deal in marine stuff - mostly motorsport - do I need to specify just "316 stainless steel" or what do I need to say to make sure I get it made of the right stuff? I think I can come up with an alternative design to offer enough clearance... got some measuring to do first though.

I'll check out the brackets but I think the aux tiller would still hit the A frame, will need to sit it on there and have a wiggle about with all combinations of each engine up and down and see what it looks like.

I shall ignore the comment about my fine trailer. No I haven't, cos at the moment it has a boat sitting on it and that won't change till about October

Hightower · 23 August 2006, 20:48

Don't bin the A frame Stephen. Turn it around 180 degrees and mount on the inside of the transom on spacers as already mentioned. I'm a big fan of the A frame as a safety device, it's a very handy grab handle at the business end. What else would you lean against when having a wee

.

jwalker · 23 August 2006, 20:49

Quote:

Originally Posted by BogMonster

...it would only be a couple of hours work with the right tools and a bit of know-how,....

Famous last words.

Yus deer ayill bee inn forr mee tee inn arfannawur.......not!

BogMonster · 23 August 2006, 21:03

Quote:

Originally Posted by Hightower

Don't bin the A frame Stephen. Turn it around 180 degrees and mount on the inside of the transom on spacers as already mentioned. I'm a big fan of the A frame as a safety device, it's a very handy grab handle at the business end. What else would you lean against when having a wee

.

I'll chop off the wiring on the weekend and have a look at that idea before I break out the grinder. Still going to get a quote for a stainless A frame though, as the one on there looks a bit crap!

cheers

Stephen

Alex Brown · 23 August 2006, 22:09

I have a Humber Destroyer 6m, and the aux engine went on the back dim problem.

I think as said earlier on this thread, your engine is quite wide, whereas mine is quite narrow. My a-frame is on the inside of the transom, but I can't see how that would make much difference. The engine does nearly 360, but I get more than 180 degrees out of it which is great cos you can make the boat behave just like a tug with a Z-Drive underneath

edit: sorry, I have just seen - my a-frame curves over the tubes the moment it is above the transom which allows the engine to go in place.

If you want any more pics, let me know.

-Alex