Building a boat trailer

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Steviecracknell

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I am contemplating a trailer build, double axle and brakes. I would be greatfull if anybody could guide me in the correct direction with regards to any information relating to road legal construction. The boat is an Arden 4, weighing around 2 tons, any guidance on this subject would be very helpfull.
 
I believe that all "new" trailers have to be rated and plated, ie. certified for road use. This would mean that you can no longer easily build your own trailer due to this certification process.

Pre-existing trailers are not retrospectively checked.

But this is only a belief, I wait to be corrected.

EDIT:

Found this...

1. If you are going to build you own trailer it will need to inspected by the Vehicle and Operator Services Agency. The cost of this is £ 70 for under 3.5 tonnes and for anything over the cost is £ 145. For further reading and to ensure that your trailer will pass, you can read what the ISA inspection manual says.
 
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I think that so few people seem to build their own that little information exists.

The Indespension manual used to have sample plans of trailers but I am not sure if they have updated this book.

Because you have to have "type approved" brakes etc. it is less economic to home build than it used to be.

Peak trailers are a useful source of parts because they build axles to your dimensions. I think they are also cheaper than Indespension.

http://www.peaktrailers.com/
 
Boat Trailer

You might look at Dunbier Boat Trailers (google) they are Australian but might give you some ideas. They are really big boat trailer builders.
You really want a boat trailer builder. A flat bed modified for boat is no good as boat will be too high off the road. You need as low as possible to enable boat to float on and off trailer in as shallow water as possible.
Further boat trailer builders will be able to fit brakes and suspension capable of taking salt water emersion.
good luck olewill
 
It makes perfect sense to aquire a second hand trailer and then modify to suit your needs, but, as I have the required skills to manufacture a custom built trailer, which would be exactly to my specifications, and ultimately brand new, also, built at a fraction of the price of an over priced branded one, this would be my prefered choice. Thanks to everyone for the contacts,

Stevie.
 
If you look on the Cornish Shrimper owners site, there is one built by an owner. He used air springs so it can be lowered for easier launching.
In your place, I would get two rear axles off a FWD van of suitable load cap. So, brakes spings etc taken care off. Renault Master are about right. The rest is tube fabrication.
I would do it for my current build, but at 1400kg it is way over the limit for self build here (500kg). The design/certification makes a one off impractical. As far as I can see, you are OK in the UK.
A

To add, my choice of springs would be Timbrin/Aeon rubber units. Light and a bit self damping. The UK agent is near Cambridge (Foxton) I made a box trailer recently from Seat Marbella running gear and used two Aeons to up the capacity to 750kg. £50 the pair and the Seat bits were €80 from the scrappy with as new tyres. Did the same for my small sailing boat, but made wishbones out of the solid axle to lower the launch height. Coil springs from a Clio.
 
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Steve, I've built one for a boat similar to yours, did a lot of research, I posted a similar thread sometime ago, I've pasted it here, if you need names and numbers PM me and I can help you out.
Also if you want a copy of my plans or specifications let me know.

"I have built my own trailer for a 25 ft fin keel yacht, and I'm very proud of it too!
The key is to do a bit of research and you can build a perfectly road legal trailer reasonably cheaply.

First of all I looked round a few boat yards to find a trailer that would be suitable for my boat. I took detailed dimensions of these commercially built trailers and used these as a basis for my own. Material size was important, together with size of welds and any bracing etc.

I then examined the NTTA website which gives clear information of maximum sizes, loads, wheel sizes etc for the type of boat you wish to tow. http://www.ntta.co.uk/

I found a good company which sells trailer packages (at very reasonable rates), these people do a coupling, axles (made to any size) brake cables and fittings, wheels, tyres and mudguards in one package: http://stores.shop.ebay.co.uk/RPH-Tr...34Q2ec0Q2em322

I designed the trailer in Autocad (but a piece of paper, pencil, ruler and protractor would do!) and built up a steel cutting list. I could then work out the weight of the frame as the steel manufacturer gives the weight in kg per metre of steel (of the section you are using).
I also was able to give the steel supplier all of the cuts required and the angles so basically what I received was a ready cut kit, I just needed to weld it all together. (Not a 5 minute job!)

After welding I fitted the wheels and coupling (the wheels were attached to a flat bar which enabled them to be repositioned with U bolts) and took them to a galvaniser.
The whole lot was galvanised (you need to drill holes in any box sections which are sealed to allow gas to escape when being dipped, the galvaniser advised me where to drill, although you do need to make sure they will not be in any areas where load is critical).

Finally I fitted everything together, got a vin plate form this person: http://www.vin-plate.co.uk/
I stamped the plate with a set I bought from machine Mart, and took it to a local weighbridge just to make sure I had all of the weights correctly marked.

The VOSA Individual Vehicle Approval Scheme does not come into force for trailers until 29th October 2012, I will be getting approval with for mine to make sure I'm covered. (there is a guide available on their website which tells you what is checked in the test)
http://online.businesslink.gov.uk/Tr...NAL_Oct_09.pdf

So was it worth it?
Definitely, I have a professional looking trailer, very well built (even if I do say so myself!) and perfectly matched to my boat.
The costs were:
Steel: £400 (I actually got it through a work contact at trade for just over half of that)
Trailer kit: £700
Bits and bobs: £100
Galvanising: £100

My trailer cost me approx £1000, A professionally built one would be somewhere between £2700 - 3500"
 
I'd be wary (with a boat that heavy) of using some of the cheaper trailer components. I've built and modified a few trailers and the stuff from people like Towsure doesn't last very long in my experience. As it will be going into water (presumably salt!) I'd be inclined to go for Indespension or another quality brand.

Using car or van axle stuff is a good idea but might get you into some legal bother. The NTTA website is good, but of you want to research the legal stuff "from first principles" you'll need the "Road Vehicles (Contruction and Use) Regulations". It, in turn, says that (current) trailer brakes need to meet the requirements of the relevant EC Directive on brakes. That's where it starts to get messy. If you buy the correct braked axles and hitch from a reputable supplier, they will have been tested and you'll be able to get some sort of proof of compliance should you need it. Although the car / van tuff might be absolutely fine, you'd have no proof that you met the requirements (unless you do a load of quite expensive testing)!
 
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