Hacking a Harbor Freight Trailer Kit – Kayak Edition

Rigged and ready

I own an SUV. This is great for most purposes, except for when there’s a need to haul things. This included my kayak and fishing gear. While I had been loading my Future Beach Angler 144 SOT fishing kayak to the top rack on my SUV for the past year, the idea of having a trailer for kayaking purposes appealed to me for ease of loading and unloading as well as time spent preparing to leave for a fishing trip. In most cases, I can leave the kayak on the trailer and just hook up and go. Additionally, there are always household projects that require hauling scrap to the dump and furniture, appliances, and materials home from the store. With these requirements in mind, I set out to design and build a trailer that will cover all of these bases for me. Like most of us, budget was an issue, so I set out to research my options, keeping in mind the total cost of the project.

Harbor Freight Parts

  • Haul-Master #42709 – 950 LB Capacity 8 ft. Utility Trailer Foldable with 8″ Wheels
  • Haul-Master #47423 – Steel Side Panel Kit (discontinued, but may still be available in some stores)

Other Parts and Materials

  • 4′ x 8′ treated plywood
  • 1″ x 6″ board
  • Eye Anchors
  • Styleworks Tough Tote
  • Trailer Jack
  • Berkley Twist Lok Horizontal Rod Rack (x2)
  • 2″ Square Steel Tubing (heavy wall)
  • 1 1/2″ Square Steel Tubing (1/8″ thick wall)
  • Plate steel
  • Misc pins and bolts as needed


The list of modifications to this trailer really fall under two categories: Those for the trailer kit in general, and those specifically for the kayak rack and fishing gear duties.

The biggest source of necessary modifications come from utilizing the Haul-Master steel side panel kit that was supposedly designed for this trailer kit. The rear of the kit has a removable tailgate. However, if you follow the instructions provided and place the floor on top of the lips of the sides, then this tailgate is NOT removable unless you choose not to have the floor extend to the back of the trailer and have the rear support provided by the rear cross-member. Additionally, the composition of the side panel kit would require some odd notches and cuts to fit in this position. Therefore, I chose to mount the panels on top of the floor.

Corner welded

Corner welded

Each cross-member of the trailer frame is attached to the side rails via three bolts: 1 on the side, 1 on the top, and 1 on the bottom. However, the side panel kit, for whatever reason, does not have holes in the corners to allow the top bolts to pass through. This left two options: Drill holes in the side panels, or remove the bolts altogether and weld the corners. I chose the latter since we already had the welder available.

Hinge welded together

Hinge welded together

This trailer was designed to be foldable, though that was not an option that I would ever be using. There is a bolt that is supposed to be holding the two halves of the center hinge together. However, that bolt was impossible to keep in place with the side panel kit in place, so we chose to remove the bolt and weld the hinge together as well as the seam created by butting the two sections together. Additionally, we bolted the two center cross-members together for added stability. Contrary to the directions, we kept the sheet of plywood in one piece and added carriage bolts down the center of the floor. This required no drilling as the holes were already there from the factory.

The ground for the trailer lighting was intended to be screwed into the frame utilizing a provided self-tapping screw and a pilot hole already present in the tongue of the trailer. Unfortunately, my trailer did not have this pilot hole, so I chose to simply use one of the bolts on the tongue for my ground location.

Tailgate with relocated plate

Tailgate with relocated plate

With only 8” wheels, this trailer sits rather low to the ground. On it’s first trip home, backing it up a hill beside the driveway, I bent my license plate in half. This prompted me to relocate the license plate on the tailgate of the side kit rather than mounting it from the bracket provided. The only issue with this is having to move it back to the bracket when hauling something that requires me to remove the tailgate. I don’t foresee this happening often, nor is it much work to actually do so.

Floor and sides complete

Floor and sides complete

One convenience modification I made was to use an eye anchor in lieu of bolts in the corners to provide additional tie-down locations for carrying loads in the trailer. Another was the addition of a utility box (Styleworks Tough Tote from WalMart) mounted onto the tongue by mounting 2 1” x 6” boards across the tongue then bolting the box to those boards. In this box I store all of my tie-downs, an adjustable wrench, my kayak seat, and various other things I may need when using the trailer. I also added a swing-back style trailer jack for ease of movement when not attached to my tow vehicle.

 Kayak Rack and Fishing Gear

Initial design. Some modifications were made in production.

Initial design. Some modifications were made in production.

For the kayak portion of the trailer, I sketched together a quick drawing with my idea for the rack. This rack needed to be removable in order to use the trailer for hauling purposes. It needed to be low for easy loading and unloading of the kayak and far enough back to be able to hold a 12’ kayak without impeding with the back of the tow vehicle.

To facilitate the location of the rear pockets, I had to drill a single additional hole in order to move the taillights and brackets back 3 inches. Other than that single, simple modification, nothing else was necessary in order to make the kayak rack work.

A raw pocket

A raw pocket

Fabrication of the rack (as well as assistance in assembly and the welding duties) was completed by my cousin, and for that I’m VERY grateful, as there is no way I could have done this by myself. After presenting him with my idea, he built pockets out of 2” square steel tube. These 8” tall pockets have a plate welded along the bottom so that the pocket can be welded along the sides and the bottom of the trailer frame side rails as well as ensuring that their height remains consistent for all four pockets. These plates also have a hole drilled in them for drainage should rain water make its way inside of them. Additionally, there is a hole drilled and tapped for using a bolt to push the 1 1/2” tubing of the rack so that it fits snugly within the pocket. The pockets and rack were then drilled for pinning them into place.

The two possible rail configurations

The two possible rail configurations (Please click the image to see the animated gif)

The original design had the pockets 4’ apart on center from front to rear. My cousin pointed out, though, that if we made this distance only an inch or so longer, then the rack bars could be “rotated”, thus placing them out of the way when hauling things other than kayaks and not requiring them to be stored somewhere other than on the trailer. Also, having these sturdy rails along the side of the trailer provides additional tie down locations for strapping loads when hauling. The pockets were welded into place per design and an additional bead of weld mounted the tops of the pockets to the steel sides, giving the sides additional stability.

Padded rails

Padded rails

My original sketched design called for 5’ long cross bars on the rack itself. Without sacrificing strength or drivability, I chose to make them 6’ long, thus making it possible to haul two kayaks side-by-side without the need for additional uprights for vertical loading. The uprights of the rack are 22” high, giving the rack just a few inches clearance over the tops of the side panels. The rack itself was constructed from 1 1/2” square tubing with an 1/8” thick wall. This steel is strong enough for kayak hauling yet not overly heavy for the trailer and handling. I then padded these rails with rubber pipe insulation from my local big box hardware store.

Rod rack installed

Rod rack installed

One last modification I made for kayak fishing duties was to add two Berkley Twist Loc horizontal rod holders, one to each side. I positioned these so the butts of my rods would be towards the front of the trailer, hopefully eliminating any tendency for the wind to want to catch the rods and whip them out. With two of these, I should be able to easily haul 8 rods out of the way of anything else in the trailer.

So Far, So Good!

This trailer is still very new. I’ve now used it for two trips to the dump during which it performed perfectly with the rack positioned alongside the trailer. I’ve done a single, short shakedown run with the kayak strapped on the rack. It also did a great job for this. So far, it seems like this trailer is doing exactly what I intended it for despite the initial frustrations caused by wanting to use the side panel kit. In total, I was able to purchase the trailer, the side kit, and all parts and accessories used for just shy of $350. If you’re considering this trailer, keep your eye out for the frequent 20% off coupons. They’ll apply to this trailer, even when the trailer is on sale. If you’re considering the side panel kit, prepare to be amazed that it ever made it to market.

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14 thoughts on “Hacking a Harbor Freight Trailer Kit – Kayak Edition

  1. Great post, very helpful!
    I realize that the side panels are discontinued, but I was wondering what you originally paid for them from Haul Master.

    Thank you,


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  3. Did you have to do anything with extending the tongue of the trailer? I am trying to find out if any modifications need to be made so there will be enough clearance for a 12 foot kayak to be trailered.

    • I made no modifications to the tongue and have had no clearance issues with 12 foot kayaks. When carrying a single kayak, I use the center of the trailer, thus there is no concern with turning. I’ve also hauled two 12 foot kayaks side by side and had no problems when making turns. You should be just fine.

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  5. I like your trailer. When did the side kit get discontinued and do you know why? I found a used folding trailer that has a side kit installed for $250 but it’s rusty and in need of some TLC.

    • This particular kit made no sense if you followed the directions. It was hinged in the middle for use on the folding trailer, but the way it sits, the hinge in the middle would be in the way so that you wouldn’t be able to fold it. Additionally, if you bolt down the sides, you’d have to unbolt one half for it to actually fold over. In other words, none of the engineering worked for what it was engineered for. The directions also called for the lip of the side to be underneath the wood floor, but doing so would have kept you from being able to use the lift out tailgate, or for the tailgate to match up with the sides. It was basically a piece of baffling engineering and quite likely a highly-returned item.

      • Thanks for the response. What year do you think the kit was discontinued? Trying to justify the purchase of this older one knowing there is some work to get it in shape vs. spending probably $100 more and having to build the trailer and my own side rails. I was planning to fold it and store it in my garage and remove the sides each time. Here is a link to the old trailer: http://lincoln.craigslist.org/grd/4794463179.html

        • I’d say that if you need to fold the trailer to store it, don’t buy a trailer with this side kit. You’d be frustrated for sure.

          As for when it was discontinued, I don’t know for sure, but when I bought mine in early 2013 it was already discontinued.

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  7. The rod racks on the inside of the trailer walls is a great idea. I’ll have to adopt that one. Thanks for the write up.

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