Bolt-together fiberglass Jeep-tub trailer kit

[bluejeep]

Well, since you asked...............

A hard cover would be VERY NICE, including.....
-light cargo carrying capabilities (things in dry-bags such as clothing, sleeping bags, etc). I'm not so into roof-top tents (I know, blasphemy right?) so wouldn't need a great deal of weight carrying capacity on the top.
-easily removable by one person would be nice, for when you need to carry stuff taller than the trailer.

Perhaps the top could be split in the middle along the fore-aft axis, hinged along the port and starboard edges, and just opened up to form higher sides for those times when taller stuff needs to be carried. Ya, I like that idea.

Better yet (Woah, somebody STOP me!), offer the top as a few options...
1 - no top
2 - split on the fore-aft axis, hinged along port and starboard sides, with stops at 90 deg and 180 degree, and include a flat surface on the underside (which becomes the topside when opened 180 deg) for use as a work surface (ie - cooking, light mechanical work, folding and packing clothing, map recon, working on laptop, etc, the mind boggles...). A slight lip along the 4 edges when in work surface mode would help with things not being knocked off onto the ground. I'm not so sure I like that lip idea tho - might be nicer just flat. Ya, flat is better. Prolly need support legs angled back to sides of trailer. I'm not a fan of support legs to the ground because when/if the suspension compresses and the legs are to the ground you place stress on the work surfaces and/or hinges, or at least cause a tilting of the surface - the lawyers would not allow that tilting simply because of the liability from spilling hot coffee...
3 - hinged along front edge, to fold 180 deg. and be flat over the top of the tongue (more stabile than hanging off the back end - would need support legs - again, not to ground) and include a flat surface on the underside for use as a work surface (see above words about work surface)

Provision for the home installer to add tie down points around the perimeter, preferably along the outside surface of each side near the top. Maybe large enuf so a few 6" lengths of Mac's Custom Tiedown Versa Tracks could be installed on the outside, with a matching length along the inside and the fiberglass side samwiched between for strength.

my $.02

[jscherb]

Any rough price point estimate for all the fiberglass parts as above?

The short answer is "I don't know at this point". But I'll explain with a longer answer by covering a couple of points...

- My main design goal for this project is to create an economical kit that can be assembled by a DIY-er in his driveway with average tools. It's a kit so that it can have a less expensive initial purchase price and so the user can build it to his budget and performance specifications based on his choice of trailer frame. I do have a good estimate of the cost of the resin and fiberglass materials that will go into molding the kit parts, and those costs are very reasonable. My goal would be that a complete, ready-to-roll entry-level trailer could be built for between $750 and $1000, which would include the tub, trailer frame and everything else necessary to tow it on the street.

- I build these projects because I'm interested in the design and construction challenge involved, and when I initiate a project I typically don't have a plan to bring the project to market. So, ...at this point I do not have a company lined up to bring these to market. When I started the Safari Cab project I did not have a company signed up to produce them, and during the course of the project I was approached by a company and worked out an arrangement for them to have the rights to manufacture and market them. I'm approaching this project the same way - I'm building this because I'm interested in the project, and hopefully some company will be interested in producing them for the market. So far a number of my projects have become projects on the market already and one other is in the process towards becoming an available project (the Safari Cab), so the track record isn't too bad.

[jscherb]

Well, since you asked...............

A hard cover would be VERY NICE, including.....
-light cargo carrying capabilities (things in dry-bags such as clothing, sleeping bags, etc). I'm not so into roof-top tents (I know, blasphemy right?) so wouldn't need a great deal of weight carrying capacity on the top.
-easily removable by one person would be nice, for when you need to carry stuff taller than the trailer.

Perhaps the top could be split in the middle along the fore-aft axis, hinged along the port and starboard edges, and just opened up to form higher sides for those times when taller stuff needs to be carried. Ya, I like that idea.

Better yet (Woah, somebody STOP me!), offer the top as a few options...
1 - no top
2 - split on the fore-aft axis, hinged along port and starboard sides, with stops at 90 deg and 180 degree, and include a flat surface on the underside (which becomes the topside when opened 180 deg) for use as a work surface (ie - cooking, light mechanical work, folding and packing clothing, map recon, working on laptop, etc, the mind boggles...). A slight lip along the 4 edges when in work surface mode would help with things not being knocked off onto the ground. I'm not so sure I like that lip idea tho - might be nicer just flat. Ya, flat is better. Prolly need support legs angled back to sides of trailer. I'm not a fan of support legs to the ground because when/if the suspension compresses and the legs are to the ground you place stress on the work surfaces and/or hinges, or at least cause a tilting of the surface - the lawyers would not allow that tilting simply because of the liability from spilling hot coffee...
3 - hinged along front edge, to fold 180 deg. and be flat over the top of the tongue (more stabile than hanging off the back end - would need support legs - again, not to ground) and include a flat surface on the underside for use as a work surface (see above words about work surface)

Provision for the home installer to add tie down points around the perimeter, preferably along the outside surface of each side near the top. Maybe large enuf so a few 6" lengths of Mac's Custom Tiedown Versa Tracks could be installed on the outside, with a matching length along the inside and the fiberglass side samwiched between for strength.

my $.02

Thanks, great input! I've got several preliminary designs for a hard tonneau/folding tent platform but I'll be finalizing them after I get the basic tub parts done. I like the idea that the hard tonneau could open to form a work surface.

Stay tuned, I'll want everyone's input on the "top" as I get to that stage in the project.

Also, I've been really happy with the soft tonneau I did for my yellow trailer, it's worked out great for my use of the trailer. But perhaps it isn't optimal for overlanding...

[jscherb]

Once I finish making the molds, I plan to build a proof-of-concept trailer. My plan for the proof-of-concept trailer is to build a "short" one, with a 4' version of the tub. Originally I was planning to use the 40" x 48" HF Mini trailer as the base, but I decided I wanted to build this first trailer on a heavier-duty base, so I'm going to use the HF 94564 Heavy Duty 4x8 trailer - it's got a 1720-lb. payload capacity, and a 5-on-4.5 bolt circle, which is the same as the TJ/YJ Wrangler. Here's a photo of the HF 94564:



The trailer will have to be shortened from it's 8' length into a 4' length; this can be done as a simple "drill job", meaning the only tool other than wrenches and screwdrivers that will be required to do the mod and assemble the trailer in the shorter size is a drill, to make a few new holes necessary for the new configuration. Here's how the conversion to a 4'x4' trailer will be done:



The trailer comes as two 4x4 foot frames bolted together in the center, so it will be assembled with only the front frame. The axle mounting bracket will be moved forward to position the axle just behind the center of the shorter frame, and the rearmost tongue brackets will be eliminated and the back ends of the tongue will be secured to the front spring hanger bolts.

I also have a use for some of the pieces from the back part of the frame that won't be used - one of the leftover beams will be turned into a mount for a rear hitch receiver, so receiver accessories like bike racks could be used on the trailer.

My goal is to build the trailer as if I'm a typical DIY-er in his home garage, without access to and special tools. So the build will be a proof-of-concept of the bolt-together capability of this tub along with the HF trailer frame.

BTW, once the proof-of-concept trailer is complete, I may offer it for sale. Since I've already got a Jeep-tub trailer, I don't think I need a second one.

[Zeep]

I'm not understanding how you will mate your adjustable side panels, to the end caps.
do you have a more detailed illistration?

[jscherb]

I'm not understanding how you will mate your adjustable side panels, to the end caps.
do you have a more detailed illistration?

The side panels themselves aren't adjustable... the side panels will be molded at whatever fixed length is necessary for the trailer tub that is being built. What's "adjustable" is the position of a dam in the mold that defines the length of the side panel to be molded.

Here's a photo from my previous project to explain. This is the mold for the side window panel of the Safari Cab hardtop. The panel is roughly 52" long for the LJ. The side window panel for a TJ Safari Cab needs to be 15" shorter than the LJ part, so I've clamped a dam in place 15" from one end of the mold. The TJ part can now be made in the same mold that makes the LJ part, but because the fiberglass is laid up in the right side of the mold up to the dam on the left, the part will be 15" shorter.



So how will the side panels be attached to the end panels? They will be done in the same way the Safari Cab hardtop panels assemble - with a 90 degree bolt flange on the end of each part. Here's another photo from the Safari Cab project, showing how the side window panel bolts to the rear corner panel of the hardtop. This isn't a great photo of the bolt flanges, but you can get the idea from these unfinished Safari Cab panels:



When assembling a trailer tub, the panels will best be assembled with a combination of bolts and either structural adhesive, epoxy or polyester resin+a small strip of fiberglass mat. They could of course just be assembled with only bolts - however disassembly is an important feature of the Safari Cab hardtop but is probably not an important feature of the trailer tub, so adhesive will be a good idea.

BTW the joint between the side panel and the end panel in a factory Jeep tub is identical - the use 90 degree flanges, the differences of course are that the factory parts are sheet metal, and instead of bolts, the flanges are secured together with spot welds.

[Zeep]

Now I understand. I thought that the side panels would all come in one size, then cut to the desired lenth.
Looks like another awesome idea. I've followed your other posts here, and on other forums. Seems this one will also have several thousand posts!

[bluejeep]

"The trailer comes as two 4x4 foot frames bolted together in the center"

How clever of those Harbor Freight folks.

Disclaimer - The following thoughts are made without knowing the strength of the trailer, nor of the tub once it's attached. I did however, own a Northern Tool trailer in the 40" x 48" version, and the materials / design / construction look very similer to the pic in your post.

Considering the potential use (some might call it 'abuse') this trailer might encounter
-pounding from washboard roads for miles on end
-twisty situations over large washout areas or sidehills or pulling over boulders
-loads on top, such as a roof top tent
with ensueing side, fatique and torqueing loads, is there any need to make use of the back 4' of frame to provide additional strength to the forward 4 feet of frame?

Additional disclaimers
- I hate to waste material that's already paid for - sorry, I'm a cheapskate.
- The twisting will most likely not be anything to worry about because this unit is not prohibited from being able to rotate assuming the hitch allows this movement.

Strengthing by doubling such as
-bolting one on top of the other - (easiest of the following scenarios to do, but creates a frame 2 times the original height - don't know if that's an issue)
-bolting each matching frame member back to back, (again, not to difficult to do, and retains the original height of the frame, but does not provide a flat outer surface to fasten to- don't know if that's an issue)
-or nesting them to form a shape similar to a 'box' frame -albiet the flanges of one would not nest inside the other, but rather overlap on top of the corresponding flange of the other. (creates issues at points the frame members join together, and most likely goes beyond the 'drill job' concept.)

Assuming the tub will fasten directly to the frame and not 'float' separated from the frame, stress would transfer into the tub. I'm thinking the more 'stiff' the frame is to resist both flexing of the frame members as well as the twisting/torqueing forces, the less chance any stress spider cracking would occur in the beautiful fiberglassing coming out of your shop.


PS - I know the resale value of your prototype would be much enhanced if it were to be painted in the dark blue that Jeep used on their 1997 TJ. Just saying.

[jscherb]

"The trailer comes as two 4x4 foot frames bolted together in the center".

How clever of those Harbor Freight folks.

Disclaimer - The following thoughts are made without knowing the strength of the trailer, nor of the tub once it's attached. I did however, own a Northern Tool trailer in the 40" x 48" version, and the materials / design / construction look very similer to the pic in your post.

Considering the potential use (some might call it 'abuse') this trailer might encounter
-pounding from washboard roads for miles on end
-twisty situations over large washout areas or sidehills or pulling over boulders
-loads on top, such as a roof top tent...

There's probably a limit to the abuse you'd want to put the HF frame to, once I've gotten their Heavy Duty trailer in my hands and I've assembled it I'll post my thoughts on its strength.

The ideas you posted (and I've omitted here in the interest of space), are good ones for reinforcing the HF frame.

I suspect many people would want to build a stronger frame than the HF if they're going to subject their trailer to off-road use more intense than gravel roads.

I do know that lots of people just want an on-road trailer for trips because the TJ especially has so little cargo space, so for them the HF frame would be perfect and very affordable.

Hey who knows, if these tubs come to market maybe the company marketing them would also offer a heavier-duty off-road frame kit...

PS - I know the resale value of your prototype would be much enhanced if it were to be painted in the dark blue that Jeep used on their 1997 TJ. Just saying.

I'm not sure if I'll leave the parts in gelcoat, or if I'll prime or even fully paint the tub. We'll discuss colors when I get to that point in the build of the proof-of-concept trailer (BTW I've got leftover black from painting my Safari Cab hardtop, and leftover yellow from painting my other trailer)

[demonslaer]

Definitely interested I would do one myself . but I don't have a space to do it . I worked in a fiberglass shop in jacksonville Fl making molds for jet boats and bushwacker tops for pickups. Keep us updated on your project the small one is what I'm looking for.