I know many (most?) of the current SB designs are too big for a combi trailer. Having been a SB man since the early noughties, I also get the impression that 'just launch off the road trailer, no problem' has been a sort of mantra to push the vague concept of 'impulse sailing', perhaps especially with the smaller boats. So I've done it for years with my Storm Petrel, fretting about the bearings and ruining one set, and trying to launch and recover in too little water (really only possible because the boat is so light) and at the expense of the facet joints in my lumbar vertebrae. Yes, I do have so-called 'bearing savers' on that trailer, which I suppose help a bit, but only a bit.
For my Trouper I decided I'd pay extra and get a combi, from Mersea Trailers (who seem to have mopped up a lot of the opposition, eg Snipe and Dixon-Bate). It came in semi-kit form, and was a doddle to put together. I've 'housed' the final stages of my boat build on the launching trolley, and used the whole thing twice for sailing. It promises to transform the whole launch/recovery experience, and do my poor back a lot of good too. It is SUCH fun to submerge the whole trolley as deep as I like and float the boat on\off it. There is a big, easily removed jockey wheel which helps. And the trailer bearings stay right out of the water! It may just be good fortune in terms of the size of my boat vis a vis the proportions of the trolley and road base, but both the boat on the trolley and boat+trolley on the road base are very well balanced, and handling the boat out of the water is, in every respect, so much easier. The whole thing seems well designed and made. The extra cost is going to be money well spent.
So to anyone setting out on the trailer-sailor adventure, or anyone thinking of replacing a trailer, I would say give careful thought to whether a combi set-up is feasible for your boat. If it is, and you can afford it (don't forget to put the osteopath's bills into the financial equation), go for it. You won't regret it. For a small boat, launching from a road trailer is, in my view, a false economy.
I suppose the question is, how big can 'small' be? Do, just for example, Wayfarer sailors use combis? In terms of Swallowboats, the Trouper and Storm 15 would be fine: what about the Storm 17 and BR 17 - pushing it a bit? Swallowboats are, because of their construction, light for their size, which helps.
Anyone else got experience/views on this?
Michael