Modifing a motorcycle trailer to SIB trailer

[Paul]

Blootac asked me to do a write up on my modification of a motorcycle trailer for transporting my SIB.
After looking around for a decent 2nd hand SIB/boat bunk trailer it became apparent it wasn't going to cheap and likely to need a few ££'s to get it 'up to scratch' wheel bearing wise.
It struck me that motorcycle trailers weren't a lot different in design and none of them would have been likely be 'dunked' into water
A look of fleabay brought this 350kg capacity 'as new' twin bike trailer local to me for £200 so the deal was done

Obviously it was too short to take my 3.8m SIB but that just meant getting some 50x50mm box section to extend the front draw bar and would also be somewhere to mount the 'A' frame winch bracket.
I placed the boat onto the trailer and by using 4 axel stands I positioned the SIB at the height and angle I desired to let me operate the launching wheels, get the transom in line over the rear beam as I was going to transport the boat with the outboard attached using a home made transom saver. This also gave me the position the adjustable bunk boards needed to be located to support the tubes correctly.

Now that I knew the width and length the bunks need to be set at I got some 50x30mm box section to mount across the trailer, the off cuts made the up rights and some 'U' bolts secured them into position.

All that remained was to piece it all together, extend the draw bar, make the 'A' frame to mount the winch, carpet the bunks and place a couple of boards to support the keel which would also give me something to walk along during launching/retrieval.
Costs, trailer £200, box section, new spare wheel and tyre, new winch with strap and hook, stainless 'U' bolts, various stainless bolts, carpet off-cut, roller for the keel, jockey wheel all came in at £100. So 2 days work and I had a bespoke new trailer for £300

The original trailer is zinc plated. My additions have been given a coat of smooth hammerite.
The trailer hasn't needed to be 'dunked' in any water as yet because I back the rig up to the waters edge, swing down the launch wheels, drop the jockey wheel, wind the front of the trailer with it still attached to the vehicle approx 2 inches and then the launch wheels are in contact with the ground. I lift the front of the boat and it rolls on the keel roller while I push it off....simples
Here's a photo of what I mean

If was to do it again I think I'd look out for the collapsible single bike trailer here http://www.davecooper.co.uk/bike_trailers.asp
150kg is adequate for our needs
Hope that the above makes some sense

Paul

[blootac]

Cheers Paul,
Looks fantastic!
I love the idea of a collapsible trailer too! Definitely worth a look!

[Paul B]

one of my mates has the 2 bike collapsible trailers and they look really well made and sturdy,

[blootac]

Paul,
What thickness box section did you use? and where did you get it from?

[Paul]

one of my mates has the 2 bike collapsible trailers and they look really well made and sturdy,

Aye Paul B, mine is exactly that model and can confirm they are VERY sturdy indeed
I went for the collapsible version because they're easier to modify with a few bolts

[Paul]

Paul,
What thickness box section did you use? and where did you get it from?

The cross beams were 50x30mm box section 3.5mm wall thickness and the draw bar is 50x50mm box section 4.2mm wall thickness from here http://www.pyramidsteel.co.uk/index.php ... tions.html
If you google up steel stockests near you then they should have what you want and cut it to length for you
The 'U' bolts, trailer parts and boat fittings etc from here http://www.trailertek.com and they are cheap, good quality with excellent service
Take a look around their website because they do loads of boaty stuff

[blootac]

Thank you very much.
I contacted that Dave Cooper about getting that collapsible bike trailer hot dipped instead of plated but he said that the bolts wouldn't fit through the holes if it was hot dip galvanised which is a shame

[Paul]

Thank you very much.
I contacted that Dave Cooper about getting that collapsible bike trailer hot dipped instead of plated but he said that the bolts wouldn't fit through the holes if it was hot dip galvanised which is a shame

That is indeed a shame about the bolts/holes once it's been galvanized
However I might still go down this route and waxoil inject the inside of the box sections to prevent corrosion
Failing that I might well do my own design from scratch once I've priced up all the gear
As I've said before, if you get the boat set-up correctly on the trailer you'll only need to push it 1-2 metres to get it into the water anyway
We'll see if I get bored during the year

[neil h]

Some nice tips in here Paul, Thanks

Have just done a deal on this, collection tomorrow. Somehow I prefer the idea of trailering it about; allows set up in advance and wash down when I get it home, without doing having to unpack and pack away again, much simpler. And with the launch wheels, never have to get the trailer wet.

Will need some mods for the Aerotec, probably a longer drawbar for a starters.
I figure the transom can sit on that rear roller. Maybe I'll add some bunks. At the very least I'll move those rear roller supports to the rear frame and change them to wooden pads for the V of the transom to sit onto.

More work to do

[Paul]

Looks like that'll be ideal mate
Not too many alterations and 'bingo'
Hard to tell from the photos but the boat and motor being very light that lengthening the draw bar shouldn't be too much of an issue.
If you're doing away with the rollers Neil, please let me know as I'm going to have to build a launching trolley soon ready for my holidays in the summer in the caravan

Paul