Converting this trailer for my Mirror dinghy to take my 3.2m SIB

[Croolis]

At this moment in time, I have no better pictures of the trailer, but it's a combi trailer made to take the dinghy you can see in the picture.

I'd like to put my 3.2m air deck SIB on it. I think it would likely make sense to not have the engine on the back while on the road, but I'd be wanting to take the boat off the road trailer while still on the launch trailer, attach engine then use the launch trailer to put the boat in the water (then I can get rid of transom wheels hooray).

The other picture I provide shows about where the axle for the road trailer would lie (yellow lines). The launch trailer wheels would be a few centimetres further towards the rear. I would be needing to attach bunks I should think for the boat to sit on.

So my questions are, I suppose, is if this whole thing is feasible. As you can see from the top down picture, the transom isn't actually that far south of the road axle. So for just transporting the inflated boat (and bearing in mind I'll be doing 3-4 hours driving with it as a rule), do we think it would all be stable etc? Seems to me that it would but maybe there's things I'm not considering.

The second part is taking the boat off the road trolley on the launch trolley, then attaching the engine and moving the boat about in that state. So there's be no support for the engine directly under the transom unless I did something to extend the trailer backwards, say add some box section, so I can have a bunk directly under the transom. And I suppose, if I was actually doing that, would I be able to have the engine on the back while driving?

Or would I need to bother - does having the engine on the transom about a foot south of any underneath support a bad idea, in either the launch trolley only scenario on on the whole road trolley setup?

I should say the engine ins a 9.9 four stroke umm 38kg I think it is.

Thx for any help and suggestions.

[User name]

I wouldn't let the engine overhang on a SIB, but depending on your metalwork skills, you might be able to knock up a removable outrigger that the lower unit could rest on when the engine is in the upright position, kinda like the 'transom saver' things.

That way, much of the weight would be inline/forward of the transom and the load would be distributed instead of weighing only on the tube mounts.

[Croolis]

Yes, I guess some kind of diagonal bar that goes up from the axle to a little bunk that will sit under the transom. Easy to just bolt together from a bit of small box section. Only for the launch trolley. I won't try and drive with it. I think the weight (and it would be most of the weight of the whole damn thing) that far back, even if it was well supported, probably not the best idea.

Cool. I'll take that boat off of ebay then. Well, put it back up again without trolley. Which will probably mean I'll end up cutting it up, because sailing dinghys with broken rudders, split gaff mast and no trailers at all tend not to be desirable, no matter how old and classic. Hope not though.

[Steve509926]

Originally Posted by Croolis

The other picture I provide shows about where the axle for the road trailer would lie (yellow lines). The launch trailer wheels would be a few centimetres further towards the rear. I would be needing to attach bunks I should think for the boat to sit on.

If you are fitting bunks, why don't you make them long enough to support the transom?
That's what I have done to my road base trailer.

[chipko]

Agree with Steve above. Bunks will easily cantilever at least 500mm or so behind last support if required, even modestly sized ones like 38 x 69mm timbers. If you need to extend more upsize to 94 x 44mm or even upgrade to using two timbers in a T shape.

Pic below of an old jet ski trailer modified for our then T38. Cantilevered around 450mm with only 38 x 69mm section and rock solid.

[Croolis]

All good suggestions, thank you. This needs looking into. And would you drive with the engine on the transom with those arrangements?

I shall have to get the boat off at the weekend and have a good look at the trailers, see what can be done.

What you mean by cantilevering in this context please? I'm not much of an engineer.