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.

[Steve509926]

No reason why you shouldn't travel with the OB on the transom, but I always use a transom saver. If I travel long distances I tend to put the OB in the back of the truck but short distances when I'm on holiday it's fitted for the duration.
This thread may help re: transom saver, I nicked the idea off chipko.

https://www.rib.net/forum/f49/settin...ler-89643.html

[Croolis]

Originally Posted by Steve509926

No reason why you shouldn't travel with the OB on the transom, but I always use a transom saver. If I travel long distances I tend to put the OB in the back of the truck but short distances when I'm on holiday it's fitted for the duration.
This thread may help re: transom saver, I nicked the idea off chipko.

https://www.rib.net/forum/f49/settin...ler-89643.html

That's a useful thread . Thank you.

[Poly]

Originally Posted by Croolis

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).

Are you planning to keep the mirror? Just wondering if you would be better keeping it on its launching trolley but sharing the same base for road trailing. I'm not sure how easy it will be to add bunks, but they may actually not be a great solution for launch (and in particular recovery). Good transom wheels have advantages - not only where you launch but at somwhere you might stop for lunch, and ultimately mean you can prep everything and then step about and go whereas a trolley requires you to launch, then go and move the trolley meantime leaving the boat somewhere...

[9D280]

I was thinking same as Poly....

I have an old Snipe Combi which I got with a Laser. Later I got a used 470 with no road trailer. Road base was man enough for the 470';s weight (and thankfully the bow-to-balance-point of the two dingies was similar (more rear overhang on the 470, as pretty much an empy shell behind the Centrboard case), but I (got) made a gunwghale hiung launcher for the 470, and towed them both about on the same road base for years.

I no longer own the Laser, but I've been having similar thoughts for my SIB & that road base...

I've not done the geometry maths here, but am I correct in thinking the Yellow dimensions are the trailer? - If so Engine on might be a bit rear heavy, but do you have a close - up of the "nose end" - If i'm interpreting your picture correctly is the Trailer - trolley clip ahead of the mast support brackert and raised? - if so, could the SIB trolley be arranged to sit further forward to get the transom over the axle?

or.... when you make / modify the SIB launcher, use the mast support as the trolley fixing wiyth a short vertical down postr that clamps in using the mast support clamp? (Guessing that trailer wasn't specifically designed for a Mirror? )

[Croolis]

Just saw Poly's post, sorry.

The Mirror has gone. It went for the princely sum of £25 on ebay auction lmao. That was after being up for weeks with no takers for the 100 quid starting bid so I went with 20 quid and it sold. But it had a split gaff mast, a broken rudder and no trailer, and it went to a young offender's institute who are going to restore it so I am content. Hopefully someone might not get stabbed or robbed from as a result of boat induced reform .

To answer 9D280's questions. Yes the yellow lines are the ROAD trailer dimensions, which is like a T piece. The launch trolley sits on top of that and has a more triangular design. Now I've got the boat off of it, I can get some good photos. If I can get home before dark today, I'll get some proper measurements and pics.

I think the trailer was designed for the Mirror, because it has welded on short vertical pieces towards the rear that sat on the outside of the boat to keep it on (you can see them in the picture), plus it has an upturned part at the front with a blunt crossbar that fits the pram hull design of a Mirror very well. Finally, it has no mast support at all because the Mirror (at least that version) has a gaff mast which comprises two masts, that when taken down can lay flat inside the boat.

However, all of these things (if I remove the welded vertical pieces because too narrow) mean that it actually looks quite useful for the SIB.

I think I will not even attempt to take the engine on the back of the boat while in transport. Because this is amateur night I think I'm not up for the risk.

I'll get those pics up and folks can throw whatever advice they want at me . Cheers.

[Croolis]

If anyone can give me an idea where I should locate bunks, should I need to attach them, on this drawing, that would help a lot.

If I'm astonishingly lucky, the framing on the trailer will match where the bunks should go and I can just clad the frame in lagging, but seems unlikely.

Cheers .

[chipko]

Personally I’d position bunks under floor, tight up to tubes and extending slightly beyond transom.

[Croolis]

Originally Posted by chipko

Personally I’d position bunks under floor, tight up to tubes and extending slightly beyond transom.

Awesome thx

[Croolis]

Here I have images of trailer. I've measured and, unless I've buggered it up, the launch trailer dimensions (not including the width of the road trailer wheels!) under the boat are marked out in yellow.

I think I'll need bunks - sadly the stretchers on the trailer are probably just a little too wide and on the vertical plane they don't sit quite right compared to the height of the welded on back bunk. The raised front part of the trailer looks like it will sit quite well with the raised part of the prow on the boat if I don't make the bunks too high. Can't really tell until I blow up the boat and start doing some real world checks.

As suggested, I'll extend the bunks out the back until they go under the transom. Maybe make some sort of detachable assembly that will extend a bit further backward for a trailer board mount.

The only things now I have to sort then is what to make things out of. I imagine some very short lengths of aluminium or galvanised steel box section to make pillars for the bunks held on to trailer frame by C clamps. I'll use properly varnished 2x3s for the bunks, maybe cover them in that carpet stuff.

Will use this for inspiration. smallribber has a vid up with it on that will help:
https://www.trailertek.com//extreme-...caAgeYEALw_wcB

I don't have an angle grinder and know nothing of metal work. I have a recep saw with a metalwork blade. That'll do it?

[9D280]

Do you have a close-up of the tow hitch / Mirror bow snubber? I think I see there is a bit of tube welded above the main road base spine, and the bow snubber post is clamped to the main "spine" and has the brace sharing the rear bolt fixing the hitch to the welded on bit of tubeoon the frame?

I may also be having a massive specsavers moment here, but how does the launch trolley fix to the road base? (or was that dealt with by the mirror being strapped down & constraining the launch trolley?

First pic I found , no association with the manufacturer or anything likje that, but is a good pic of the trolley - trailer lock) <haych-tee-tee-pee W-W-W>.tridentuk.com/gb/kbase/combi-trailers-what-you-need-to-know.html


I've got too much to type / photos to find tonight, but if you are up late tonight, look in this section for a post / thread from me dated C. June 2010 when I replaced my rib trailer. Ribs & sibs are a bit different to "solid" hulls in that often the bow / painter ring isn't right at the front.
If you could get a few inches of overhang there ('tho beware you still have enough space when coupled to allow it to turn - Blunt bow could meet back of car on a tight corner if you bring it too far forward) & if you have an estate or a "deep boot lid" that there is still clearance to open it!) then you might be able to inch the SIB / Engine forward & balance it better? (Tho' moving the spare wheel a few inches foward would be an easy way alter the overall balance... (Plenty of clamp-on spare wheel brackets in trailer shops)

I'll try & make more sense tomorrow, but need to go kip now!

[Croolis]

Originally Posted by 9D280

Do you have a close-up of the tow hitch / Mirror bow snubber? I think I see there is a bit of tube welded above the main road base spine, and the bow snubber post is clamped to the main "spine" and has the brace sharing the rear bolt fixing the hitch to the welded on bit of tubeoon the frame?

I may also be having a massive specsavers moment here, but how does the launch trolley fix to the road base? (or was that dealt with by the mirror being strapped down & constraining the launch trolley?

First pic I found , no association with the manufacturer or anything likje that, but is a good pic of the trolley - trailer lock) <haych-tee-tee-pee W-W-W>.tridentuk.com/gb/kbase/combi-trailers-what-you-need-to-know.html


I've got too much to type / photos to find tonight, but if you are up late tonight, look in this section for a post / thread from me dated C. June 2010 when I replaced my rib trailer. Ribs & sibs are a bit different to "solid" hulls in that often the bow / painter ring isn't right at the front.
If you could get a few inches of overhang there ('tho beware you still have enough space when coupled to allow it to turn - Blunt bow could meet back of car on a tight corner if you bring it too far forward) & if you have an estate or a "deep boot lid" that there is still clearance to open it!) then you might be able to inch the SIB / Engine forward & balance it better? (Tho' moving the spare wheel a few inches foward would be an easy way alter the overall balance... (Plenty of clamp-on spare wheel brackets in trailer shops)

I'll try & make more sense tomorrow, but need to go kip now!

I'll take the launch trolley off and take a photo. To answer your question - it just sits on the road trolley. There might have been a locking mechanism that holds the launch trolley to the road trolley, but can't see one and not now. But every combi trailer I've owned has really required the boat to be ratchet strapped to the whole combi trailer. So yes, I'd put the ratchet strap around everything including boat so it's all lashed together.

I don't think I'd want to move anything closer to the hitch than what is there already - as you say I think the boat would interfere with the car, might be touch and go already.

[9D280]

On the plus side, I don't need to go to specsavers!

Joking aside tho' - sandwiching a launch trolley between a hard hull and the road base proably works fine - thing with a SIB (or Rib) is any ratchet strap will tighten & loosen as the tubes in / de flate (as they will in the heat of the sun - or worst still the sun goes down and so does the toob pressure) Even if it loosens slightly then your launch trolley is no longer constrained so starts moving under the hull, chaffes through the toob, <pop> no air & the strap is as good as useless... and you then have a totally loose trolley as well as a flapping toob...

Yeah, extreme case, but some form of positive trolley fixing would be well advised.

I see you have a bracket for a centre roller / Keel block behind the axle - even bolting a bit of 4X2 to that to engage on the "hole" on the trolley frame will help. Kind of like my old Laser Combi: (see pic Not mine but it illustrates the concept- unfortunately this one has all Balack padding, but if you look closely, you'll see the two hooks over the trolley axle - what you cant see is the roller it's sitting on directly under the axle.) I'm thinking you have the two "seats" at the ends, so bolt on a "tie down hook" onto theat centre bracket. Then a cleverly applied ratchet at the front will hold it forward & engaged.

Balance will be the biggest issue with the engine hanging out behind the axle - Having said that, the trailer drawbar might be heavy enough to balance it and as I said, worst case buy a Spare wheel carrier bracket (use your fave search engne & search for "Spare wheel bracket") & move the spare forward. I've got those wheels on my Box trailer and I know they are heavy enough to resore balance!

[Croolis]

Here's a better pic of the hitch. The hitch itself is bolted to some box section that is welded on. The only thing other than the hitch that can be removed is the vertical piece. (Can't rotate the pic godammit, sry)

[Croolis]

I hadn't thought about heat etc on the boat tubes, so that's a good tip, thx. Yes, some kind of tight attachment to keep the launch trolley locked down then is required. On my other boat I had some hook type things and yes, pulling forward on a ratchet strap kept it there. I'm still going to need to tie the boat down to the launch trolley..

I won't be driving with the engine attached. Like I say, all this amateur night stuff here I'm doing concerns me enough that I don't think it's worth the risk. So I'm thinking I'll run a couple of 2x3 bunks along the frame's stretchers so they go out the back under the transom like chipko suggested.

The SIB actually weighs considerably less than the Mirror (38kg vs way over 50kg with mast), but I'm guessing (it's hard to tell when moving it about) that there's more weight at the back of an empty inflated SIB with no engine on due to the transom, dunno. If you look at the Mirror in the pic in first post you can see how much weight is out the back overhanging, but that would be counterbalanced by the considerable amount of . timber at the front of the boat compared to the back. Good tip on using the spare wheel to balance out.

If I mount the box section pillars that support the bunk on the inside of the frame stretchers, that should bring the bunks to bear just where chipko shows. Again, can't be sure. I shall cut a lap sort of thing into the 2x3s so they sit snugly on the welded on back bunk thing, so as to maintain an even height. Hopefully the raised front part of the trailer will accommodate that, dunno yet.