Weight Distrubution and Sway Control for boat trailer
 

Has anyone ever used a weight distribution and sway control hitch and installed it on their boat trailer?

Yes!

We have used one towing a 42 Fountain and I must say that I am truly impressed. It improves the ride, handling of the truck. It also reduces any swaying of the trailer. I would highly recommend! By the way, once the kit is installed, removing the bars is a very quick process. No I do not sell these. The comments are from actual use.

I have never installed weight distribution or sway control on a boat trailer. Weight dist. is usually required when there is extreme tounge weight, and the tow vehicle's suspension is compressed too much. Sway bars also help when towing trailers in excess of 20' long, and 2 axels or less on the trailer.
Most of the larger boats are now trailered on tripple axel trailers, and the weight is distributed properly, and they tow/track very well. Also, boats dont usually have a lot of tounge weight since most of the weight is the engine and fuel.

Just my two cents...

never on a boat trailer but on a 31' toy hauler....it should be the same...I won't tow without it...how long and how much wight???

I have a 12K lb trailer with 1,400 lbs on the tongue (I put it on a truck scale). With the added leverage on the hitch, it really taxes the rear tires limits (unless you have a dually).

I installed a Reese WD setup, and when I re-weighed it on the truck scales, it had moved around 400 lbs to the front wheels.

Tows much better than before. The only downside is that you have to remove the bars for tight turns.

Read your car/truck owners manual for maximum tow capacity.
MAx capacity requires a WD hitch . Weight carrying hitches drop towing capacity considerably!

Example ; a 1998 Grand Cherokee has 6500lbs cap with WD hitch, 5000 with weight carrying.

I have seen them but don't understand how it changes the weight around. Is there a simple explanation?

The same concept as a truss vs a rafter when both are supported at the ends (front tires and trailer tires) and in the middle (your rear truck tires/suspension). The rafter will bow under weight where the weight is applied putting more weight on the rear tires only, for discussion. It's easy to bounce the rafter up down, making it spongy on your rear tires and springs.
The truss won't deflect giving that bouncing feeling and will distribute more of that center force to the far ends, which would be your front tires and trailer tires for a more even weight distribution. The bars and chain in the WD setup a work on the same principle as the diagonal bracing in the trusses, basically. The wieght is always the same with or w/o the WD setup. You are just changing where it is.