Weighed my boat and trailer today. ???

tractoman

Petty Officer 1st Class
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Jul 16, 2009
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I had to go to DMV to "verify" the VIN on the trailer, don't ask, and on the way back I went by the dumps and the guy let me get on the scale. I couldn't unhitch the TV but while hooked up and with only the 4 trailer tires on the scale it was 3620 lbs. I don't know the tongue weight.
The question is how much weight should I add for the trailer still being hitched to the TV to get a ballpark on the weight of the whole rig. The boat weighs 2750 per the Sea Ray specs and its a tandem trailer. It's got about 20 gallons of gas in it now and maybe another 75 lbs of skis, ropes and stuff, so if I add 15% to the scale weight, does this seem reasonable or is this too much? It puts me at 4163 lbs which seems like it's in the ballpark. Unfortunately, it was just too busy to unhitch while I was there today.
Towing the boat sure makes me wish it was spring.
 

a70eliminator

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Sep 9, 2007
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Re: Weighed my boat and trailer today. ???

I recently weighed the trailer for my 20' bow rider boat, the trailer is a single axle steel box trailer and weighs 830lbs. I would guess yours weight at least that unless it's alluminum, add your 2750lb boat and your at roughly 3500lb add fuel gear and tongue weight and it sounds about right, but i don't know about the tongue calcualtion.
 

smokeonthewater

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Dec 3, 2009
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Re: Weighed my boat and trailer today. ???

is there some reason you need to know? if it is for trailer tags or trailer axle weight rating then it's the weight on the trailer tires that matters..... if it's for some other reason another trip to the scale will tell you..... weigh the tv with the boat hitched to it and then drop the boat somewhere out of the way and weigh again... subtract the two numbers and add that to your trailer weight from before and viola presto alacazam or alluvpeanutbuttersandwitches!
 

jeeperman

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Aug 2, 2001
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Re: Weighed my boat and trailer today. ???

You already have the 3620lbs that was the four trailer tires on the scale?
Can you lift the trailer off the ball? If yes, you can probaly guess pretty close.
Or
No need to go back to the scale if you have a bathroom scale, a length of 2x6 or simular and something else as thick as the bathroom scale.
Place 2x6 on top of bathroom scale and the spacer at each end of 2x6.
Place trailer jack in center of 2x6 and lower until trailer is level.
Read weight on scale and multiply by two.
Add that to your 3620lbs.

I think that is the SilverTip Tip.
 

Silvertip

Supreme Mariner
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Sep 22, 2003
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28,771
Re: Weighed my boat and trailer today. ???

If all you need is an approximation, you have 3620 for sure so tongue weight will be in the 7 - 15% range. That means tongue weight is 253 - 513#. My guess is it will be in the 10% range or 360# range which is why the 2x6 trick is used. Most bathroom scales don't go that high so you use the board and multiply by 2. Just basic physics.
 

reelfishin

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Mar 19, 2007
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Re: Weighed my boat and trailer today. ???

http://www.iboats.com/Safety-Trailer-Jack-800lbs/dm/view_id.685891

At $106+ Shipping, that's an expensive option, not to mention that the actually tongue weight on the ball itself or its effect might be quite different than where the jack is mounted. (The jack on my boat is nearly 40" back from my trailer coupler).

I take it your after the weight for the entire boat and trailer combo for registration purposes? If so I'd round up to the next even 500lbs to cover you for added weight and fuel in your boat in the worst case scenario.
If the reason you couldn't unhook the trailer was that the scale used left and right pads all you need to do to get total weight would be to take two blocks or jack stands and a piece of wood to bridge the weight onto both scale pads or ramps. If they won't let you unhook, then have them weigh the whole rig and simply subtract the known weight of your tow vehicle. This can usually be had from a sales brochure, be sure to add for the amount of fuel in the tank.
I'm not knocking the bathroom scale method but they don't always tend to be all that accurate and it's much easier to get a complete weight taken all at once on the same scale.

If you need the weight for DMV purposes, then they usually don't need you to be all that precise as they will often round up to the next 1,000 lbs or next weight class it falls under.

I have a 3100lb rated tandem axle 24 roller Load Rite trailer here with a manual winch which is 22' 6" long and it weighs 987 lbs on the a scale empty. It has 14" steel wheels, steel fenders, and is about 20 years old. It has no side bunks, no guide on posts, and no mounted spare. The tires are 14" and it has no brakes.
 

truckermatt

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Mar 29, 2009
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Re: Weighed my boat and trailer today. ???

ok..... i am gueesing that you were on a scale that only allowed each axle to be weighed... If the weight on your trailer axles is 3620 lbs, then to find the amount on the tongue.. all you have to to is rescale twice....
----once with the boat and vehicle together, but just weight the rear axle of the veichle... a
----and then unhook the boat somewhere safe.
----then weight just the vehicle rear axle.

then subtract the two... then you will know for sure.
 

j_martin

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Sep 22, 2006
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7,474
Re: Weighed my boat and trailer today. ???

ok..... i am gueesing that you were on a scale that only allowed each axle to be weighed... If the weight on your trailer axles is 3620 lbs, then to find the amount on the tongue.. all you have to to is rescale twice....
----once with the boat and vehicle together, but just weight the rear axle of the veichle... a
----and then unhook the boat somewhere safe.
----then weight just the vehicle rear axle.

then subtract the two... then you will know for sure.

That'll be off because weight on the trailer hitch also transfers weight from the front axle to the rear axle. You either have to unhitch and weigh the trailer alone, or weigh the whole rig, then unhitch and weight the TV.
 

smokeonthewater

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Re: Weighed my boat and trailer today. ???

this was solved in posts 3 and 4..... He clearly stated in the first post that the reason he couldn't drop the trailer was because he would have taken too long on the scale.
 

tractoman

Petty Officer 1st Class
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Jul 16, 2009
Messages
370
Re: Weighed my boat and trailer today. ???

I did weigh the trailored boat and TV together so I have that number. Just not the TV alone. I'll try to run by there with the TV alone sometime and get that weight too. I am just trying to get the ballpark weights so I know what I am trailering and so that when I load more gear I will have a rough idea of the total weight. Also makes me feel better that I don't have a bunch of water logged foam.
Thanks for all the input. DMV has the trailer down as 400 lbs by the way but they don't jack you up for more $$$ until you're over 6000 lbs so it really doesn't matter.
 
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