Thread: My camper trailer build - a different approach?

Ill back you up on the 50mm ball Harlie.

Sure, all the offroad trailers Ive built been involved with are boat trailers with long distances between hitch and axle BUT we have never once had an unhitch?
All over the cape, through gulleys with verticle walls, launching off steep banks (verticle) generally going everywhere youd pull a camper plus some?

And with a boat trailer that gets used round town some fancy tow hitch would be a hassle!
S

One of the reasons given to me years ago for the development of "poly-block" products enabling 360 deg rotation was in response situations where caravans would roll and cause the towing vehicle (usually Holden/Ford sedans & station wagons) turn over as well...obviously the good ol' 50mm towball held firm!!!

Caravan suspensions / braking systems have improved as have towing vehicles... the 50mm ball lives on!

I had grand plans of staying home and building a kitchen unit over the Easter Weekend, but a very late decision to flee the city changed that... Trailer has now covered just over 1000km, only problem was a slightly warm hub, backed off the bearing nut by one slot and all is good.
Used it as a test trip, we stayed with family and did a couple of mods to the tent, still need to sort the "tropical roof", and buy a new mattress.

Hi – I’ve not updated this for a long time, buy thought I would post up a pic of the latest doings…

The camper – as a unit, has been completed (and used) for a while now, including full kitchen, pressure water and gas plumbed, a duel battery 12 volt system with lighting built into the internal tent bows. Solar panel is still to come and I would like to add a 240v system but that can wait.

As mentioned at the start, the original requirements for this build included the ability to transport a Tinnie – not a “car topper”. few years ago I purchased a 4.2m hull, took to it with the welder for mods, then fitted it out including a 30hp 4 stroke, it’s proved to be a great little boat so the dream was to be able to have it on hand at camp.

I’ve spent several weekends lately (sorry neighbours) welding up the rack system, and Fold-up boat trailer for use a camp. I originally wanted to purchase a Fold-up but none of the manufacturers would make one to suit the (larger) Tinnie, so back to the PC for a design session, weld it up and drop all the pieces off at the Galvanizers for hot dipping (man has that gone up in price!) . It took me half a day to assemble it once all the Gal bits were back home – there was quite a few threads, pivot points ect to clean up, but the finished product is great, complete with independent coil suspension, just have to add tail lights and get it registered.

When we built the chassis for the camper, mounts were added for the rack system to allow mounting directly to the chassis. It’s got a fair bit of weight to deal with so it is very substantial. As an example the rear cross bar is 130mm deep in section and the front rack (of 3) is a truss system made with 75x75. There are tie down points on the racks and under the chassis to allow two sets of tiedowns front and rear. There are two (fwd-aft) bars that need to be removed (r-clip and pin at either end) to allow the tent to unfold.

Today was the big one – would it all work - this afternoon with three of my mates, the boat was loaded on for the first time, winched on (and off) with an electric winch. A couple of problems were encountered giving me a short list of changes todo, but the test was declared a success and we went for a drive. Two of the boys followed with a video cam (to film trailer behavior). From the driver’s seat and from behind it rides and handles perfectly - after we added 20psi to the tyres.

Attached pics don't include the Fold-up mounted in its transport position.

Some said the plan was too ambitious – including 3 of the 4 guys on my driveway today, right up until we drove it - what a change in attitude!!

Boy - that's a monster build! No low height carparks with that on the back

What does it weigh all loaded up?

Nice work
David

Harlie,
I like you thinking outside of the norm! I still dont understand why people travel all over northern Oz with a 3m tinnie but great big camper/caravan. Surely a proper boat is more of a priorty than somewhere to rest your head

Im a little scared though! Your chassis came in at 250kg, completed trailer 400kg.
And now 1500mm above the deck you have:
Hull weight 200kg ish, 30 Honda 75kg + frame + gear
I be guessing near 400kg.

Wont the rolling moment be scary high! Or low as the case may be.

I know its mostly for blacktop and beach runs, but that is almost worse! A high speed swerve and sway could end nasty. The problem is it would be a scenario unlikely to show itself until the limit is reached. Static testing wont reveal what happens at 80km/h on an off camber corner swerving to miss a wayard touritst in a Britz camper.

(Just last week we finished beefing a mates 445 trailer for offroad work. Had the axle in its old location. On test drive, if you threw the wheel at 80 the trailer got a sway and wanted to pull the rear of his cruiser into the ditch! (exagerating a bit but it certainly wasnt safe). We had changed the springs from poxy trailer springs to a modified pack out of 79 cruiser. The softer spring rate allows the trailer to float over the rough stuff but seemed to set up a scary harmonic at speed once upset (even with dampers). We shifted the axle back 25mm and it was fixed! Small changes to geometry make large changes to a dynamic system.)

Would there be some value in fitting a heavy antiroll bar across the axle of your rig? It may give some limiting effect on cross axle spring rate changes in a sway? It could be easily removed when the boat is not up top?
Or maybe fill the chassis with lead to get the COG down!
Maybe the new rangas with tow control etc etc really are that good???

Im sure you will test it out but it would be a shame to see such great work lay down on its side...or worse?

Regards,
Steve

Thanks Steve, your points are all valid and exactly what we’ve been talking about and penning for the last 4 years when ever this project surfaced.

I have no illusions about the dangers mentioned and certain design features were implemented for the handling of the boat alone, most notably the positioning of the axle. By using an absurdly long draw bar and the unique rack system the axle in relation to the boat is further back than on any boat trailer, for exactly the situation you mentioned. As you can appreciate this axle can’t be moved, but the racking has allowance for the boat to be moved forward or back if needed.

Your example of geometry is interesting as I had the exact same ditch directing experience with a large boat some 10 years ago during testing. I moved its axles 110mm to solve it and as you mentioned a seemingly small change makes an enormous difference.

I’ll add a swaybar to the possible list, at this stage that has not been considered. Observations while (100kg) I stood on top of the trailer on the rear corner, grabbing the top of the boat and tried to rock it as hard as I could notice that 80-90% of movement was in the tyre sidewall, which is currently a point of discussion.

Testing will indeed continue – this is a prototype, to my knowledge unlike anything around, there’s some time yet before the whole rig leaves town – some points have been identified for change on the camper too, like relocating the pole carriers down lower and forward (they are bloody heavy). Also the Fold-up, gas bottle and (boat’s) fuel tank were missing from their draw bar mounting positions. On Sunday the run was kept relatively short, the day’s goal was testing loading/unloading – we honestly didn’t plan on going for a drive. However we picked some poorly surfaced streets and once happy didn’t slow for the corners, video footage from behind has been reviewed so we all have a good look at what it was up to. Every thing has now been dismantled to check for any bending or signs of weakness or flex. Now I'm happy with the racks structure, and noted mods are made we will assemble again and go for a long run, give it a good test and make adjustments (or modifications) where necessary – at the end of the day, if it’s not stable and safe the project will be abandoned.

I’m planning a trip to the weigh bridge on Friday, fully packed including food and water but without the boat, Fold-up and racks – I already know their weights.

A fascinating design and build.