How we calculate

Loaded trailer weight

1. Boat weight from the boat maker's own spec page. If the maker's figure is "dry" and doesn't clearly include the engine, we assume it doesn't and add one, which can double count (that's on purpose: it errs heavy).
2. Engine: the heaviest Yamaha outboard variant in the boat's maximum-HP class, from Yamaha's published weights (Yamaha notes weights are for the shortest shaft and exclude oil and prop, which is another reason we round up via the gear allowance):
   • Up to 40 HP: 223 lb (Yamaha F40, source)
   • Up to 60 HP: 247 lb (Yamaha F60/F50, source)
   • Up to 70 HP: 253 lb (Yamaha F70, source)
   • Up to 90 HP: 362 lb (Yamaha F90, source)
   • Up to 115 HP: 386 lb (Yamaha F115, source)
   • Up to 150 HP: 566 lb (Yamaha F150 (heaviest listed variant), source)
   • Up to 200 HP: 568 lb (Yamaha F200 (heaviest listed variant; also used for 175 HP), source)
   • Up to 300 HP: 588 lb (Yamaha 4.2L V6 F225-F300 (heaviest listed variant), source)
   • Up to 350 HP: 653 lb (Yamaha 4.3L V6 F350 (heaviest listed variant), source)
   Jet boats (Yamaha) and inboard ski/wake boats already include engines in the maker's weight.
3. Fuel: full tank x 6.1 lb per gallon of gasoline.
4. Gear: +10% of boat + engine + fuel for batteries, anchor, coolers, safety gear, T-tops and options.
5. Trailer: the maker's published figure when there is one (Yamaha lists "dry weight on trailer"; Tracker/Sun Tracker list an average boat+motor+trailer package weight). Otherwise a clearly labeled estimate of 35% of boat + engine (minimum 400 lb). We picked 35% because Yamaha's published boat-on-trailer weights show factory trailers adding 26–34% of the boat's weight. Use the real trailer weight in the checker if you know it.

Live-well water, a full freshwater tank, wake-boat ballast and a cooler full of ice are NOT included beyond the gear allowance. Drain ballast and livewells before you tow.

Truck ratings

We use the conventional (ball-hitch) ratings printed in each truck maker's own towing guide or spec sheet for the model year. Each engine/package shows the lowest and highest published rating across cab, bed, drive and axle choices, because your exact truck could be the lowest one.

Pass / Caution / Fail

• PASS: loaded trailer is at or under 80% of the lowest published rating for that engine/package, and payload checks out where it's published.
• CAUTION: within the rating but with less than a 20% margin, over the lowest rating but under the highest (only some versions qualify), or tongue weight at 15% would exceed the payload.
• FAIL: heavier than every published rating for that engine, or tongue weight + two adults exceeds payload.

Tongue weight and payload

Tongue weight is 10–15% of the loaded trailer (Ford says 10%; Chevrolet says 10–15%). It counts against payload, along with everyone in the truck. We assume a 300 lb driver + passenger (the same 150 lb-each assumption Ford uses). Toyota and Ram publish payload ranges, so we use the low end. Ford publishes only a best-case max, so Ford results say CHECK until you enter your sticker payload. Chevrolet and GMC's towing charts don't list payload; use your sticker.

What this isn't

It's not a substitute for your truck's Safety Compliance Certification label (door jamb), Tire and Loading label, owner's manual, hitch label, or a trip across a CAT scale. Brakes, weight distribution, tires and state trailer-brake laws also matter.