Flatbed tilt/snowmobile converted to hold PWC

[TheBlueMartin]

First off let me say (now that I'm done with it) this is not something I recommend unless you are very limited on parking as I am. The time it took to do it right was way more than I expected. If I had the parking space, $1k for a used trailer seems like a better deal than this.
I had a 1999 GTX fall in my lap last fall, to go along with my 1996 GSX. They are usually going to stay on their hoists in the water at the lake we are next to, but occasionally I want to take them to my hometown near Lake Michigan. I have a golfcart and zero-turn that I like to be able to move when needed, and getting this trailer keeps me from needing a pickup instead of an SUV.
I bought a cheap used trailer so I could replace everything and know it was done right. I replaced the wheels, tires, hub seals, wires, and jack....as well as the plywood. I always use stainless steel fasteners.

[TheBlueMartin]

It was pretty rough when I got it home. But I stripped it down and built it back up:

[TheBlueMartin]

Mock-up was a lot of time. I do automotive research and development for a living, so I'm pretty specific on making sure everything works out. Each bunk is built to the angle and width of each hull.







(The level is perfect, per the bubble....it was just hard to hold the camera to take a photo)



First attempt at a mock-up.



K447 on here gave me the idea to tilt the bases instead of the top, changing the pressure angle. That was a huge help.



Ripped the runners



Mocked them up and figured spacing. The base boards are placed on the support beams under the decking for weight loading.


Set it on the ground to test. Found there was more curve in the hull than I expected, and the 4x6's needed to curve more with them. The middle cross-support was removed, and that seemed to do the trick letting it sag a little in the middle.


Stapled on carpeting and sat it on place to figure CG...it was a lot farther forward than I was hoping.




It sits really well. As you can see I had to put an eyelet farther forward to hold the bow hold-down. More on that later.

[TheBlueMartin]

The boy was determined to help me bolt in the E-track tonight. Took twice as long, but it was worth it.

[K447]

What will you be using to prevent the hull from sliding forward or backwards, particularly during hard braking from highway speed?

Normally this is done by the winch stand and bow roller on a purpose built PWC trailer. Not only does the bow roller support the very front of the hull to prevent the hull from bobbing up and down as the trailer flexes and bounces along, it also serves as a strong 'structure' to keep the hull in place during extreme braking events (and some level of controlled hull movement during, heaven forbid, a forward collision).

[K447]

Looking at the exposed frame structure of the original trailer has me wondering if the torsion axle could be shifted rearward. That would allow the PWC (and it's center of gravity) to also move rearward, moving the bow closer to the front of the trailer frame.

It is not unusual for PWC trailers to have the back of the hull hanging out a modest distance behind the trailer frame.

Shifting the axle and hull locations would (somewhat) increase the tongue weight, but that might be tolerable. If need be the tongue can be strengthened and stiffened by adding/replacing with a stronger/bigger box tube.

[TheBlueMartin]

Looking at the exposed frame structure of the original trailer has me wondering if the torsion axle could be shifted rearward. That would allow the PWC (and it’s center of gravity) to also move rearward, moving the bow closer to the front of the trailer frame.

It is not unusual for PWC trailers to have the back of the hull hanging out a modest distance behind the trailer frame.

Shifting the axle and hull locations would (somewhat) increase the tongue weight, but that might be tolerable. If need be the tongue can be strengthened and stiffened by adding/replacing with a stronger/bigger box tube.

Yeah I had given a lot of consideration to moving the axle back, even if I used the current rear holes for the front studs and drill new ones for the rear. 10 inches of rearward CG shift would be a big help. However with it being 20 years old and I'm nearing it's capacity limit of 1420lbs as-is, I'm not sure I want to add additional stress to the frame. Getting a new tongue made to add support seems like a waste of money on something this old. I could probably sell the trailer empty and buy a larger/newer one for less money/effort than that.

What will you be using to prevent the hull from sliding forward or backwards, particularly during hard braking from highway speed?

Ah, the famous photo of the GTX on the roof. That one never gets old.

At the moment I have the E-track with twin 500lbs straps making a V onto the rear of each hull. After I get the final configuration laid out (maybe moving the axle) I plan on adding some sort of bracing to the front of it, but I haven't made a final decision yet. Adding a winch stand with a roller on it would be the best option, but that'd take some time figuring geometry for making it all work.....going back to my first point, its better to just buy a 2-place trailer. However I only have room to park one trailer, so for now this is my best option.3

https://www.etrailer.com/Boat-Trailer-Parts/CE-Smith/CE31013G.html

[TheBlueMartin]

Got the second one mounted and moved over today. Lots of little things to do, but it’s all working so far.