A buddy used silicone spray on the Bunks ..He usually would unhook everything on the boat and back the trailer down into the water and the boat would float loose and he could take a line and pull the boat free .... first Time with the silicone he backed down the ramp and the boat flew off the trailer out into the river!!!

Don't forget you need to have the tongue the same height on the scale as it will be when hitched to the truck.

Any pics of when this didn't work so well? Like when a 35 Fountain is sitting in the back of the pickup or laying in the street!

weigh the trailer empty, then weigh it with the boat.

do the math to determine where the cg of the boat is, and where the cg of the boat needs to be to get 10% on the tongue.

the boat pivots around the axles, so when you go to the scale, pull up so the rear bumper of the truck is hanging onto the scale, and weigh it with it hooked to the truck, then weigh it with it resting on the trailer jack. the difference is your tongue weight (doesn't matter that the trailer jack is further back than the actual hitch)

you need to know tongue weight empty, tongue weight loaded, axle weight empty, and axle weight loaded. consider all the axles together, it doesn't matter if there's one, two, or three. call these numbers twe, twl, awe, and awl. you will also need the length of the distance from the axles to the tongue (average of the 2 or 3 if a multi-axle trailer)... call this d, and call the location of the cg in front of the axles cgd (cgdl for loaded trailer, cgde for empty trailer, cgdb for boat without trailer, but still referencing trailer)

twl/(twl+awl) = cgdl/d -> twl+awl is not going to change as you move your boat, twl will though. d doesn't change. cgdl/d has to equal .1, but it doesn't now, so do this calculation twice, once with cdgl/d = .1, solve for twl, call this twl1, and once with your actual measured twl solve for cgdl (cgdl = twl*d / (twl+awl).

twe/(twe+awe)=cgde/d -> twe, awe, and d are measured, calculate cgde -> cgde = twe*d / (twe+awe)

(twl-twe)/((twl+awl)-(twe+awe)) = cgdb/d = (cgdl-cgde)/d -> it follows that cgdb = cgdl-cgde.

measure everything (twe, twl, awe, and awl, and d), calculate cgdl, cgde, and cgdb as is. be consistent in units, the way i wrote everything, it's all unitless, but when you actually start calculating you need to stick with lbs or stick with kgs, and stick with inches, feet, or meters.

set cgdl/d to .1 and solve for cgdb. subtract the calculated cgdb of your boat the way it is sitting from the cgdb you calculate when you set cgdl/d to .1, and that's how far you need to move your boat forward.

or something like that. I think i got it right but i'm not garaunteeing i didn't miss something. Also, if you have a multi axle trailer, as you move the weight forward more weight will go on the front axle of the trailer, slightly throwing off the calculation by effectively reducing d. Shouldn't be enough to invalidate you calculations, as you're only looking to be in the ballpark of 10% anyway, a little less even.

Must be getting real close to launching the Formula if you're down to the tongue weight dialed in. :D:D