acdii

Sounds like you got it! That is the missing link most people fail to get and wind up driving an overloaded rig. They look at the towing specs and figure because their truck has that engine, and that gearing for that particular cab/bed style that they can get a trailer that weighs that much, only to find, OOPS, it can't! Always read the fine print!

Turbo_Bimmer

Ok, so here is my new calculation, more realistic:

GVW: 4409
2 passengers: 330
tonneau cover, tools etc: 110
payload: 300
EQUALS: 5149 (new truck minimum weight)

Tongue weight 765 (9% of 8500)

GVWR: 6010 minus 5149 truck weight minus 765 tongue equals 96lbs spare , still under my maximum of 6010.

Now!
GCWR: 13300
minus 5149 minimum truck weight
EQUALS: 8151 maximum trailer weight.


If I move the boat to reduce the tongue weight to 7%:
New Tongue Weight : 595 (8500 * 7% = 595)
old tongue weight - new : 765-595= 170 lbs less in payload that can be applied to trailer
8151 + 170 = 8321 new maximum trailer weight.
Not a big difference but if it is required, why not.
**EDIT** AGAIN; gee, I made the same mistake again. The tongue weight is used only to see if the payload is not maxed out, and doesn't affect the calculation of the maximum trailer weight. So in that case, moving the boat to reduce the tongue weight has nothing to do with the trailer weight. It's hard to remove the tongue weight from the calculation when my mind always used it for many years...

The trailer weight assumes a full fuel tanks (400lbs), so, for a long trip I could keep the boat fuel tank as empty as possible to save a few hundred pounds and fuel it near the ramp.

So now I'm relieved. Numbers over 8000lbs make me happy.

Thanks all for the help. I finally saw the light LOL.

Simnut

Now....you also have to remember that the tongue weight comes OFF the GVW of the trailer also! The truck is carrying it...not the trailer wheels.

Turbo_Bimmer

Yes, that's true.
I imagine that a boat dealer should match the proper trailer to the boat they sell, but it is wise to double check, in case someone swapped the trailer during the lifetime of the boat.

acdii

I think you are over thinking it. Boats tow far different than cargo or travel trailers, their mass or CoG is centered between the axles, or on the axle depending on the number of axles. In that type of trailer configuration, sway is pretty much nicked, much the same as a horse trailer. Getting the boat balanced on the trailer is the most important part. As long as you don't make the boat tail heavy it should tow just fine. Someone on the forum tows a pretty large boat with his F150, I just don't know who, but bet if you browsed through the post pictuer of truck and trailer you will find it. Might want to PM him to get some pointers on setup.

Turbo_Bimmer

acdii, I know what you mean. The reason I'm asking all those questions, is not really for the tow ability of the trailer, but more for the legal side of it.
Where I live (Montreal), having a truck/trailer reasonably over the GCWR won't get you a ticket, and in the event of an accident, if everything 'LOOKS' reasonable, in good condition etc, it will just be treated as a regular traffic accident.

That being said, I want to tow in the US, and I read in many places that in the event of an accident, especially if people are hurt, they investigate more, and if over the GCWR, criminal charges can be used against the driver of the 'overloaded' vehicle.

So, I prefer to understand how to calculate everything and make sure I'm not over the GCWR and don't spoil the family vacations by spending a night in jail...

Jeff1024

Not sure it is considered "pretty large" but here is our 24ft boat behind our 2015. Its right at 7000lbs ready to go in the water. Rear of the truck squats a bit but handles it pretty well other than that. We only tow about 5 miles to and from the ramp but so far no problems. Hope this helps you feel a bit better?

acdii

That makes sense, and I sure don't blame you. I think the simplest way would be to load it all up ready to travel and go to a scale. Your main concern then is to make sure you don't overload the truck itself. As long as the truck is within reasonable weight you should be fine. If it is over 100 pounds, that is not something to be concerned with, if you are over by 500 pounds, now that would be something to be concerned with. If you have the boat, you can make up a bathroom scale TW scale. Get 2 2x4x7, screw or nail them together, and make 1' marks across it. Get a cheap bathroom scale, a patio paver that is the same thickness as the scale, and two 1' pieces of pipe, can be electrical conduit, copper pipe, etc. Place the paver on one side of the tongue jack, with a pipe at the 1 foot mark on the 2x4, with the joined sides facing up, place the jack at the 2' mark, and the second pipe on the middle of the scale at the 4' mark. Put all the weight on the 2x4 so it is completely off the hitch (forgot to first mention to hitch it to the truck, unless you are really strong and can lift the trailer tongue with your bare hands). Take the scale measurement and multiply by 4, the number of marks between the pipes. That will give you the tongue weight. Also put the bars on the frame if using WDH. Subtract this from your truck payload to get what the truck has left. If you have a scale ticket of the truck with the gear and people, then subtract that from the GVWR to determine how much actual payload is available and see if you have enough for the tongue weight, if not, move what you can to the boat.

Simnut

You're a smart young feller acdii!!!