Upper PWC carrier on a boat trailer

[Spades]

I want to be able to tow my 17' boat and PWC together, so im thinking of building (or having it built for me) an upper level single PWC carrier on top of a boat trailer. Im planning to upsize my trailer meant for a 19-20 ft boat for more weight capacity. I have a few ideas already, but im looking for more input and ideas. Anyone have pics want to share it and its design?

Boat weighs 2100 & PWC weighs 740 (STX-15F)

My ideas below:
1. Swiveling rack - I prefer to raise & lower the rack using a winch rather than using hydraulics
2. Rigid rack and use boom lift to raise & lower the PWC
3. Rigid rack and some kind of sliding ramp for a winch to pull up & back down the PWC
4. Ive seen the Jet trax assembly that bolts to the pickup bed of a truck, so i thought to simply buy one of those and somehow adapt it to the upper level of the rack

[steve45]

I really think that you'd be better off building a new custom trailer rather than modifying an existing trailer. That way, you can design in the extra strength you'll need in key areas. With a combined weight of about 3500 pounds (with fuel and trailer weight), you would need a minimum 3500 pound axle. You would be much better off to go with a tandem axle design. Modifying your existing trailer would require a new axle and springs. Don't know how the springs are mounted, so it may require more than that.

If you go with a winch, you would definitely want an electric winch. A manual winch will get away from you and hurt somebody. Hydraulics aren't bad, but you would have to design it properly. With either system, I'd use a trailer-mounted battery to operate it. I use a trailer-mounted battery to operate the electric trailer jack on my double PWC trailer and I mounted it inside the storage box with an external pigtail that attaches to a battery charger. You can charge the battery from the +12v wire on a 7-pin jack on your tow vehicle, too.

You would definitely want appropriate locking mechanisms in place to keep the 'Ski from moving around while driving.

You should check your state requirements for trailer brakes depending on the total weight of the trailer.

[K447]

20 foot boat
Well, how long a trailer are you comfortable with?

My initial thought is a custom trailer, with the PWC bunks mounted forward of the boat winch. Makes the trailer longer but keeps all the weight on the same plane, near the ground. The only 'moving part' would be the boat winch tower being removable or able to fold down.

The PWC bunks can be extended along under the boat hull. Maybe touching the boat hull, maybe a bit below. When the boat is floated off, the PWC can then either slide all the way down the long bunks or back the trailer in deeper and then float the PWC off.

Build the trailer with parallel frame rails for the boat (which is normal) but extend the parallel rails forward to encompass the PWC bunks. The trailer frame Y would be in front of the PWC.

I have a double axle trailer, smaller overall than you would need, but it has a center forward position for a PWC.
In addition to the center forward PWC bunks, having flat deck areas on either side up front can be really handy.

http://greenhulk.net/showthread.php?t=290011&p=3102655&viewfull=1#post3102655

[Jonesyfxr]

The other option would be to install bunks perpendicular of the tongue, then load the PWC from the side. This way the trailer tongue doesn't have to be a mile long.

[K447]

... install bunks perpendicular of the tongue, then load the PWC from the side...

Current model PWC are generally longer than the maximum allowed trailer width of 102 inches (8.5 feet).
Mounting the ski sideways would create a rather wide load.

Seadoo Spark are 110 and 120ÔÇØ long.
Yamaha EX is 123ÔÇØ


Some of the stand-up and older single seater PWC might be short enough to be legal when mounted sideways.

[Jonesyfxr]

Good point.... my buddy mounts his stand-ups sideways.

[Spades]

20 foot boat
Well, how long a trailer are you comfortable with?

No, its a 17' boat, and im planning to upsize to a trailer meant for a 20' boat for the extra weight capacity. I do not like the idea of extending lengthwise because when the boat is unloaded, all the weight of the PWC will be in the front. Also when i plan to remove the PWC at home, all the weight of the boat will be at the rear

[K447]

No, its a 17' boat, and im planning to upsize to a trailer meant for a 20' boat for the extra weight capacity.

I do not like the idea of extending lengthwise because when the boat is unloaded, all the weight of the PWC will be in the front.

Also when i plan to remove the PWC at home, all the weight of the boat will be at the rear

Yes, a long(er) trailer with PWC mounted in front of the boat will create a heavier tongue weight. The trailer load balance would necessarily be biased forward, heavier tongue weight fully loaded that a 'normal' boat trailer.

That fully loaded forward weight bias needs to be enough that when both PWC are removed and the boat is on the trailer the trailer still has enough tongue weight for stable towing.

On my three PWC trailer shown I move the winch posts for the two rear skis backwards when the front ski is loaded, and move the winch posts forward when there are only two skis on the trailer, thereby adjusting the trailer balance and tongue weight. The tongue weight with my trailer is always heavier than a typical two PWC trailer, even empty.

For your situation, how much heavier is the boat that the PWC?

[Spades]

OK i missed mentioning that there are days where i may take out only the PWC, and or the boat

I have a separate PWC trailer for when i want to take out only the PWC, so i will transfer it at home... When i do this the boat would be all the way at the rear which would cause the weight balance to shift. I cannot drive it in this condition and would have no way to slide the boat forward to correct the balance. That is the reason i am wanting an upper-deck design so that it would maintain its balance with or without the PWC on top.

[K447]

OK i missed mentioning that there are days where i may take out only the PWC, and or the boat

I have a separate PWC trailer for when i want to take out only the PWC, so i will transfer it at home... When i do this the boat would be all the way at the rear which would cause the weight balance to shift. I cannot drive it in this condition and would have no way to slide the boat forward to correct the balance.

That is the reason i am wanting an upper-deck design so that it would maintain its balance with or without the PWC on top.

My suggestion was that the boat be loaded onto the 'long' trailer such that the weight balance is stable and safe for road travel without the PWC loaded. Boat weight positioned forward enough to create proper (at least the minimum safe %) tongue weight.

When the PWC are also loaded the tongue weight increases. Heavy tongue weight does not create a handling concern as long as the trailer is strong enough for the extra forward load, and the tow vehicle is rated for the entire tongue weight of the 'forward weight biased' trailer with PWC loaded.

A refinement would be to have an adjustable location winch post for the boat. Which would allow the boat to be shifted forward when the PWC are not present.

In terms of using the trailer to launch PWC vs boat, an alternative to aligning the PWC with the boat axis would be to mount the PWC bunks at an angle ahead of the boat, diagonal to the trailer centerline. Whether this would be advantageous in your use cases, perhaps.


Regarding carrying a full size PWC up above the boat, this is not without downsides. That is almost a half ton of weight positioned quite high, not including the added weight of the lift mechanism. The center of gravity of the fully loaded trailer would be substantially higher, with negative effects for trailer handling. Not just side to side load wobble over road bumps. During hard cornering, such as emergency lane change maneuvers at highways speeds (perhaps with off camber road angle) the fully loaded high CG trailer could lean over the outside wheels and potentially roll the trailer.

A few years ago a friend was towing a double PWC trailer, which one might expect would be super stable even in a hard turn. Another vehicle pulled out from the roadway shoulder while he was approaching at highway speed (maybe 50 mph). He took evasive action and swerved to avoid collision. He did avoid contact but the trailer inside wheel lifted high off the pavement, high enough angle to break the tie down straps and drop the Seadoo onto the road. If a double PWC trailer can lift a wheel, a boat trailer with even higher center of gravity could.

The lift mechanism itself must also be resilient, not just strong. Side to side, twisting and fore-aft flexing during road travel can fatigue and weaken metal.

[Spades]

No, im set in my thinking of the upper-deck assembly. Yes both have their quirks, but the upper-level method is the lesser evil than dealing with a 30+ ft of trailer, not to mention parking space, not just at home but when out camping with it, and visiting other places in between the main destination. Its just a huge hassle

[K447]

... I’m set in my thinking of the upper-deck assembly. ... the upper-level method is the lesser evil ...

Will you be doing your own engineering and fabrication of the PWC lift mechanism on the boat trailer?

[Spades]

I have a few general designs that ive seen and liked, im trying to get more input from people, like things to avoid or watch out for. And obviously from the builder as well. Ive built an upper-level rack for gear on top of my FE double trailer and turned out really nice, its been in use for the past 4 years, but im not confident to build a PWC carrier myself. My rack typically holds about 200 pounds of gear, in fact the rack itself probably weighs as much as the load

[Team Bilford]

Since you are in SoCal, contact Fritz at Shadow Trailers.