I bought a standard single axle 8 x 5 trailer with with cage. It was then a relatively simple job to cover the top and front with sheet metal. Gear is locked away and protected from sun and rain from above, but not the sides. It gets rolled into the shed at home.
Before
After
Used 25 x 25 tube welded together with a $100 Aldi gasless mig welder. Skinned with aluminium composite panel stuck to frame using
3M VHB Tape. Finished off with angle trim fixed with long rivets to panel/ frame. ( Photo wont rotate )
30 something year old trailer that is in it third incarnation. Originally built by a friend of a friend as a windurfing/camping trailer with a canvas enclosure on the frame. I had a cheap Chinese camper trailer tent on it for around 5 years. that's when I fitted the new axle and bigger wheels.
Nose cone is fabricated from timber by myself as I have zero welding skills. Marine ply attached to original frame. And a split door on the back using old tail gate as well. One of my sailing mates has a full door, which I considered doing, but he needs to open it before he parks because of bollards, then can't lock it after. Great to hide from a shower under, but a bit of a PITA I think.
Has survived 4 years in this form, including an accident which wrote of my tow vehicle.
Inside racks are 1 inch square aluminium tube with those plastic joints from Bunnings. Not ideal, but easy to use. A few have cracked over time and needed to be replaced. Couple of dollars each, so no biggy.
I would suggest keep it as short as you can. I can fit a 3 boards 10 sails and 3 booms etc in this and I can park in a standard car park at my regular spot. Longer than 295 needs to go on top. Was built to suit that size at the time.
Best things are Galv frame and marine ply, no rust issues at all. No chucking salty gear in or on my car. No trying to remember everything I need. Pretty secure at the beach and at home.
Would change a few things if I had the time or motivation, but for now does me just fine.
Trust me if I can do one, anyone could.
Jacko / ballast spot on that's what I'm talking about.
Peter, I was not ever talking about building a whole trailer, rather just an enclosure. No need for 3mm steel, and $500 covers it easily if one shops cleverly and/or uses secondhand signwhite sheeting. No way would I suggest somebody just goes ahead thinking they can build what you or Kato do.
I hybridised, custom-building a removable windsurfing enclosure that sat on a stock 8 x 5 box trailer. Rego is therefore just the flat $66 p/a without inspections. Enclosure made from welded Steel RHS, aluminium composite panel etc as per most examples you are seeing. White-side-out ACP is awesome at keeping boards cool, being both reflective and modestly insulative. The enclosure is removable (without having to remove the W/S gear) via 4 manual hydraulic jacks, allowing access to the box trailer for more conventional trailer duties. I built out over the wheel-arches, but I must say the extra rearward visibility created by the small cut-in above the wheel arches but beneath the box his very handy for rearward visibility of cars behind me. I think total cost was around $1600 (on top of the stock trailer), comprising steel RHS, Aluminium Composite Panel, Plywood for the floor, fittings (hinges), fixings (rivets), aluminium trims to finish off around the ACP, vinyl liner to contain dripping salt water. Not as cheap as I thought it would be, but the perfect customisation to what I wanted to carry (including a kayak, 11"11' SUP, formula board and 6 other boards) is priceless.
I posted a fairly comprehensive update on the build at the time on the forums if it's of interest to you.
HIJACK ! Ballast, thats the BEST WOD ive seen! So practical, will fit in a skipbin perfectly. 
Select to expand quoteMark _australia said..
Jacko / ballast spot on that's what I'm talking about.
Peter, I was not ever talking about building a whole trailer, rather just an enclosure. No need for 3mm steel, and $500 covers it easily if one shops cleverly and/or uses secondhand signwhite sheeting. No way would I suggest somebody just goes ahead thinking they can build what you or Kato do.
Ok My misunderstanding!
One other thing Im feeling is that here in NSW as with so many other things we are over regulated and over controlled. Here draw bar minimum has to be 50x50x6 Angle (hence my comments about penetration) as a for instance. To be legal the trailer must not be altered in any way from its original compliance inspection. E.g if it was a box and you add a cage it's supposed to get a now compliance cert, or the addition of any welded bolted or permanently fixed on fitting. So bolting on a tradies side door tool box, need a new cert. Last January just up the top of the hill from me (Roseville Bridge for the sydney siders) during the last week of double demerits they did a blitz on tradie utes and trailers over 400 fines issued over 3 mornings for unsafe loads (no net/straps) and un compliant alterations to vehicles and trailers. Mate lost his licence in one hit trailer ute and load trifecta. Looks like you get away with much more in other states.
Never used EA for a drawbar.Not much Torsion strength in angle. 70x38x2.5 RHS for light trailer
90x50x3 RHS for a heavier one
All Dura gal
Built a few duragal boat trailers. Only ever use box sections. Wouldnt even consider anything less than 100x50x6. Its amazing just how much thatll flex with only 1200kg load.
^^^^^ Yes correct , but there are other structural elements in play not just the box section. It's not like a boat trailer with no support. Built right the frame will supply additional strength and control the flex.
Select to expand quoteolskool said..
HIJACK ! Ballast, thats the BEST WOD ive seen! So practical, will fit in a skipbin perfectly.
Yeah Olskool. I modified it so I could store it in the trailer. Wouldn't want it getting stolen.
The other theory is that if a chassis can flex from one end to the other stresses are not concentrated as they would be if there was a sharp transition from stiff to flexy. Check this video showing how the Landcruiser chassis is flexing from one end to the other under the rubber mounts loosely connecting it to the body. Landcruisers last forever but the axles, springs and drawbars fall off trailers after a fraction of the punishment. Lack of shockers on the typical trailer don't help. The specialist off road trailers, having shockers and soft, long-travel suspension are built to last but they cost a bomb.
Select to expand quotepeterowensbabs said..
One other thing Im feeling is that here in NSW as with so many other things we are over regulated and over controlled. Here draw bar minimum has to be 50x50x6 Angle (hence my comments about penetration) as a for instance. To be legal the trailer must not be altered in any way from its original compliance inspection. E.g if it was a box and you add a cage it's supposed to get a now compliance cert, or the addition of any welded bolted or permanently fixed on fitting. So bolting on a tradies side door tool box, need a new cert. Last January just up the top of the hill from me (Roseville Bridge for the sydney siders) during the last week of double demerits they did a blitz on tradie utes and trailers over 400 fines issued over 3 mornings for unsafe loads (no net/straps) and un compliant alterations to vehicles and trailers. Mate lost his licence in one hit trailer ute and load trifecta. Looks like you get away with much more in other states.
Are you sure about the draw bar minimum specs? Is there even a specific document that describes this stuff other than the general RMS document that describes the fitting of lights, reflectors, and the like?
I registered a home built trailer from scratch a few years back, and the guy that inspected it was a guy that did a lot of caravans and trailers. He seemed to apply more of a 'the workmanship looks good, and the general construction appears sound' approach to it. At the time, the requirements called for rated/stamped chain for the safety chain, which was almost impossible to get, but he accepted the non-rated chain and argued that it was more than sufficient for a safety chain. (Me, I am one of those people that prefer two chains... just in case.)
I used RHS for the drawbar and from memory it was 50x75 at 3mm, and it was fine. I don't even know how you would compare angle to RHS and argue whether one is stronger or not.
This guy was pretty spot on. When I mentioned thinking about going home and trying to drop the weight below the magic 250kgs, he advised me not to bother as a trailer this size was always heavier than 250kgs and I wouldn't be achieving much. In retrospect, I might have registered it as a flat platform instead of sides, which would have kept the weight down.
I am also not sure about your comments about being able to get good welds from home equipment. Granted, my crappy cigweld mig is meant to use a 15amp circuit, it welds fine. I would love to have some decent gear though and I am sure it makes things easier.
Select to expand quoteFormulaNova said..
I don't even know how you would compare angle to RHS and argue whether one is stronger or not.
Curiosity got the better of me and I did a little more googling. It looks like the box section vs. C section frame debate has been going forever with no clear winner. (OK not angle but maybe half way between). Ford and GM only recently went to box sections on the full sized utes whereas the Toyota Tundra and Tacomas have gone to C section.
www.treadmagazine.com/features/open-c-versus-boxed/
... move to a different state. Problem solved.
WA is windy in summer, VIC has Sandy Point, QLD has 25 degrees for most of the year.
Select to expand quotemathew said..
... move to a different state. Problem solved.
WA is windy in summer, VIC has Sandy Point, QLD has 25 degrees for most of the year.
Sez the Transient Windsurfer Mathew. How do you do it? Whats the secret ? Youre not of the pension age.
Select to expand quotemathew said..
... move to a different state. Problem solved.
WA is windy in summer, VIC has Sandy Point, QLD has 25 degrees for most of the year.
I tried to move to Vic back in 2008... just before the GFC hit, and I could not find a job anywhere! No one was hiring at all... except the job I had just left back in Sydney.
Do you want another GFC? 
Select to expand quoteolskool said..mathew said..
... move to a different state. Problem solved.
WA is windy in summer, VIC has Sandy Point, QLD has 25 degrees for most of the year.
Sez the Transient Windsurfer Mathew. How do you do it? Whats the secret ? Youre not of the pension age.
Mat has a very understanding boss who has no idea of what state he is in. But his work keeps seeping down the phone lines
Select to expand quotekato said..
^^^^^ Yes correct , but there are other structural elements in play not just the box section. It's not like a boat trailer with no support. Built right the frame will supply additional strength and control the flex.
I've seen your craftsmanship Kato
Select to expand quotechoco said..kato said..
^^^^^ Yes correct , but there are other structural elements in play not just the box section. It's not like a boat trailer with no support. Built right the frame will supply additional strength and control the flex.
I've seen your craftsmanship Kato
Cool, I went looking for that as well! With his special, articulating rear steering trailer. He should stick to the nail-gun. Maybe lash a 90x45 to it and nail it down?
I was waiting for someone to post that .
The first time I've ever used "off the shelf" U bolts to fix the axel and springs together. I normally use HT bolts in a cage set up. The issue with U bolts and a square axel is the corners create a stress point . This is what failed when I was bouncing along the LG track to the point. It was a rough track last year. But it went back together with no issues or damage to the chassis.
I don't often use off the shelf products , preferring to build my own systems with know properties. Another learning experience
^^^ nice setup...... and that reminds me also
4ft wide
if it sits in the same wheel track as your vehicle it is sooo much more comfy on sand, no side to side wriggle as it tries to climb up a wheel rut (and the drag that comes with it).
Hard to find, but an 8x4 trailer to start building on is ideal
Select to expand quotegmitton said..
Nice trailer, thanks for posting. Did you build it yourself?
Had it built by a custom trailer maker. All aluminium and stainless but cost a bit. Been happy with it though. Hold 7 boards, 20 sails 5 booms and 10 masts. Took three designs to get it right though! Mark is right about the wheel tracks...
Just a word of advice from a mate. If you DO spend time designing the perfect trailer; earning the money for the perfect trailer; getting the perfect trailer built at significant cost; then start off by measuring your driveway.
Apparently it's a really bad feeling to get your new and expensive pride and joy home and suddenly realise that you are either going to have to knock a wall down, or sell the trailer and get a new one built that is about 6" narrower but just as expensive. A true, sad and costly story.
Select to expand quoteolskool said..
HIJACK ! Ballast, thats the BEST WOD ive seen! So practical, will fit in a skipbin perfectly.
I assumed that was just so he could fit it in the trailer
