Trailer setup and dimensions

Now that the hull is complete, I'll need some way of  launching. In NZ, boats are usually launched directly from a road trailer, where the trailer is partially immersed in the tide prior to launch.
I note from Proteus and Swefn pictures that you use a launching trolley, hitched to a road trailer for transport.
I think I might try and copy that idea. Three questions,
1.  What is the width between the mudguards of the road trailer to provide clearance to the hull. I have a central frame trailer with 1.3 metres ... which I reckon should be sufficient.
2. Where is the load fulcrum, that is, where should the fulcum be relative to the length of the boat. I calculate it should be reasonably balanced if the pivot point is just forward of the skeg, so there is a downward load to the towing ball of 20 kg or so, ex the trailer beam, which will be another 10 kg.
3. that leaves about 1.3 metres of overhang from the stern to the transom, which is not directly supported by the trailer. Does this cause any problems? I've always assumed that there should be a support close to the transom when trailing
Regards
Nigel

Hi Nigel.
In the UK people use both both methods, usually depending on where they launch.
Many of the places I would launch in the South of England have Gravel "Hards"  which are basically areas of sloping shingle but with limited or no vehicle access, so the boat has to be pushed by hand over the gravel. The launch trollies are lighter making this easier and there is the advantage of not getting the road wheels and bearings submerged in salt water. Having said that many people do manage with just a road trailer, I'd advise using Bearing Buddies to keep the water out, and never put hot bearings in the water.

I bought a second hand combi trailer off FB which is designed for a longer boat but means I can still use the bike rack on the back of the van.
A couple of photographs to give you an idea of the set up.

 





The width issue isn't so much clearance for the hull as clearance for the launch trolly wheels but I've seen people use flat bed trailers with the trolly sitting higher, clear of the trailer wheels.  

We all have removable front castor wheels for our launch trollies which make life much easier. The trick is to have the boat balanced on the trolly with very little weight on the handle. This makes it so much easier to move around.  The transverse support needs to be just behind the central bulkhead/forward end of the side seats.



My draw bar is quite long which adds plenty of weight at the hitch, maybe 20kg.  I drive about 40 miles each way to my favourite launch spot and she seems to be very happy at 60mph.

The overhang isn't a problem, just make sure you put any heavy items up forward, or better still in the car.  In the UK /EU new trailers have to have the lighting board attached to the trailer not the boat. Check your regs.

Have Fun.
Regards
Graham.

Adding to Graham's useful info -
These pics might save a few words.
(I’ll do measurements if needed.)
Combination Trailer.
Rear 45 degree view of Morbic on trailer.
Morbic cautious first launch (first few seconds of video).
Morbic on trailer.
Morbic on trailer - 45 degree view. Zoom in to see mudguard clearance.
Launching trolley is useful in this sort of context!  Across the sand.
As for the light-boards – I dunno, but won’t get excited or paranoid about it.  Can’t imagine police anywhere checking age of trailer.  Might crop up as a bolt-on offence if one was stopped for some other contravention.  

Thanks for the info, will set about design I. The next few days. Been a bit windy here.