TB's custom PWC trailer build/conversion

[TimeBandit]

Join me on this custom trailer build-thread.
I decided that I'm going to build a custom trailer for my fishing Waverunner. As I look around the garage and the backyard, I might just have enough parts to get a decent trailer realized. My goal is multi-faceted; 1) I am looking for the lowest resting profile possible as the ski sits on the trailer. This is going to help me deploy in shallow ramps and/or beach access areas.2) I want to utilize a Timbren axle-less suspension. I've had these laying around over 4 years now, and I think this is a perfect application for them. Don't know what Timbrens are?? Stay-tuned. 3) strong - I'm a fan of over-engineering where it counts, and since this trailer will be getting a lot of use, I want to insure I end up with something a bit more substantial than the A-typical pwc trailer. 4) Fit inside my garage! It's going to be tight, for sure.

Here's what I have to work with:

(above) Its a massive 23ft+ aluminum I-beam trailer. ÔÇ£TriumphÔÇØ trailer. I grabbed this thing derelict and dirt-cheap a few years back with the intent of provisioning it for my 18ft Starcraft bug-out boat. Well, lets just say not all projects of mine get finished, so it's now destine to become one helluva stout PWC trailer. The ONLY things good here are the two I-beams, the receiver, and the wench leg/tongue. The I-beam are in great shape, 3ÔÇØ wide & 4ÔÇØ tall, 1/4ÔÇØ thick aluminum. It measures over 23ft long and 6ft wide (nearly 8ft if you include the original axle/tires. Let's just say its got to go on a serious diet to get it down to being anywhere close to being PWC-friendly.

So I've measured the thing head to toe, so that I could scale-down a drawing up on the PC. While the above image is just a bitmap, the original version on my PC is a vector drawing of ÔÇ£objectsÔÇØ that I can just resize and drag around the screen. I also added the basic footprint of my Waverunner so we can get some perspective here. Top-half of the drawing, section (A) on the pic above is how the existing trailer would line-up with the Waverunner. Yeah, not realistic. So, the added ÔÇ£red linesÔÇØ depict where I intent to chop the beams. When put back together, I should be closer to what section (B) represents, which should be closer to 15ft long and 4ft wide.

The hard part now is figuring a safe way to cut these I-beams

[TimeBandit]

I made decent progress this week. I got a hold of a portable band-saw, and with some patience I was able to cut these I-beams down to a more manageable size. Above pic, the two cut-down beams along with two v-bend 3ÔÇØ aluminum cross-members I picked up at my local trailer supply store, the layout offers a rough idea of where I'm going with this.



Ok, so the 1st hurtle to get over is how to reintegrate/attach the two beams to the galvanized tongue. Rather than added top/bottom plate brackets, a can of fiberglass resin caught my eye on the shelf. So fab'ed a pair of wedges, which will function as tapered spacers (see above).





Ok, so these wedge spacers installed. I ran a bolt all the way through everything to the other side. Along with construction adhesive, this is quite a sound connection ÔÇô more than I thought it would be in-fact. Due to the beams being 4" tall & the tongue 3", I'm going to need another spacer for the bottom.



(above - excuse the mess - this is a construction-zone) So here's what I have roughed-out so far. Looking a lot like small boat trailer . . . yup !

Now it's on to figuring-out the suspension parts & how exactly I'm going to do the bunks. . . . . .

[CFLFX]

Any more progress? I was thinking of doing a similar project.

[TimeBandit]

Thanks for following this thread . . . yes, made a little more progress.

I've been battling it out, trying to find a way to adapt these Timbrens to I-beam ÔÇô something they were not designed for. These axles are best suited for box-trailers, aka utility lawn trailers. If this were the case ÔÇô they'd bolt right-up. But since I-beam have no sides, I can't use the side fasteners. Now I could go the real easy-route & just drill through the I-beam bottoms, BUT I don't know where the balance-point is going to be yet. I won't know until the ski get loaded, so I'd like to design this so I can side the axles forward/rear to fine-tune tongue-weight.



These are (above pic) 2,000lbs Timbren axles. So my solution was to clamp the axles to the bottom of the I-beams. I welded a pair of bracket "ears" which will allow me to use U-bolts. But the welding heat destroyed the original powder coating. So in an effort to restore, if not make better, the corrosion protection, I first hit them with zinc paint. Heavy coats applied. I believe this is called cold-galvanizing. Once that cured, I added a coating of spray rubber bedliner, which made them black again.
BTW, I see now Timbren has gotten smart (since me buying mine 5 years ago) as they now offer them in hot-galv treatment.



So in the above pics, the U-bolt brackets worked great! They only need to stabilize the axles to the under-side of the I-beam, as the main load weight is supported naturally.




ok, so a "problem" I have realized when mounting Timbrens to I-beams, is that one must utilize the cross-beam support option !! There was way way too much side-to-side sway & wheel bowing as the I-beams want to twist under load. Therefore, a last-minute fabrication-job, I whipped-up this steel cross-beam (above pic), which will plug-in to each of the Timbrens. I had to notch/step the center beam unfortunately, as my measurements indicate I may not have room to clear the ski's keel once loaded due to how low it is planned to ride.

I feel like the biggest hurtle is past now, with the suspension settled. Now it's onto the bunk design and fabrication. . . . .

[TimeBandit]

Progress:

So this update will be on the bunks.
I decided to go traditional wood with bunk carpet. Sure, I thought about rollers, and composite slicks, but considering everything has a trade-off, you can't go wrong with what has been proven to work.
That said, I aim to turn the wood up on the long-ends, as depicted below, for the added strength. I know what your are thinking ... while this does risk having greater pressure-points / less-flex against the hull, a) I think the older & solid 2005 SMC hull can handle it, b) plus I'll be adding a keel roller up forward ÔÇô that's in addition to the bow-stop support. I'll also trim the board ends to exactly match the hull rise, so I estimate I'll have two 7ft beams of 2" wide each distributing the ski's weight, plus the two additional forward supports.



Above pic. I found some scrap tubing pieces. These are .25 inch walled, and the best part is that a typical 2x4 fits inside !! So I cut them into really nice U-channel brackets for which I'll use U-bolts to secure them to the cross-members.



Above pic. Here are the bunk brackets mounted up. I fitted pressure-treated 2x6 (yes 6 inch) lumber for added rigidity than just 2x4s. As you might see, I tapered (cut) each end down to a 2x4 dimensions. Why? Well, once again I'm trying to keep the ride height of the ski as low as possible, and 2 inches is 2 inches.



Above pic. Here is a shot of the bunks completed. All black. Here's what I did. Rather than wrap the entire board with the carpet, I decided to first primer/paint it gloss black. Next, I added a strip of rubber (toolbox liner) to the top edge. BTW, found a new product by LiquidNails called Fuze*IT. Sticks to anything/everything, so I use this to affix the rubber strips to the lumber. Next, I wrapped a section of bunk carpet over the bunk tops to cover the rubber & top board portions ÔÇô once again Fuze*IT along with stainless staples. The end-result are bunks that comfortably support the ski, add a degree of resistance, yet allow the ski to slide-off without excessive abrasion to the clear-coat of the Yamaha hull. Hit the bunks with a bit of Fluid-Film with keep them slick enough for shallow deployments.

[K447]

... The end-result are bunks that comfortably support the ski, add a degree of resistance, yet allow the ski to slide-off without excessive abrasion to the clear-coat of the Yamaha hull. Hit the bunks with a bit of Fluid-Film with keep them slick enough for shallow deployments.

The Fluid Film application may attract and hold road grit which could scratch the hull over time.

Consider a spray lubricant that dries such as Liquid Rollers.

[spaceman]

I use WD40 on all my bunks, have for almost 20years, cheap and works.

[TimeBandit]

Actually, for my past boat setups, I've used pure Silicone spray, the quick-dry aerosol type, and while it worked great, I found out the propellant was a bit of a solvent towards plastics. And given that bunk carpet is synthetic - I did not want to take the risk.
Then switched to DuPont Chain Saver (aka dry lube) with very very good results. It has Teflon, and one application lasted for several launches at a time.
Agreed that FF would likely attract sand/dirt more so, thus I'll be sticking with (or not sticking - haha) with DuPont.