Tongue weight / gross weight questions

Boat trailers and trailering

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Mark-NJ
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Tongue weight / gross weight questions

Post by Mark-NJ » Sun Apr 01, 2018 8:58 am

OK...confusion reigns.

Last year I finished my Ski-Tow. I bought a Load-Rite 14F1000WT (1000 pound capacity), on the recommendation of the local dealer, based on the specs of my boat. I asked him about tongue weight & balancing the load, etc., and he said "this is a small boat....you'll be fine just the way it is." With that notion in mind, I trailered the boat from NJ to Maine and back again. No issues, no problems, no noticeable change to steering or breaking. All good!

We trailered it without the 15HP engine on the transom....it was wrapped in packing blankets and strapped down inside the hull of the boat. Total weight of the boat & engine is right around 875 pounds.

This winter I've rebuilt a '57 35HP Johnson that will be on the transom when we trailer it. That engine weighs 135 pounds. Being that the increased weight will be behind the axle, I was concerned that it might decrease my tongue weight......and too little tongue weight is dangerous.

So yesterday, with no engine mounted, I measured my tongue weight. I couldn't believe my eyes! With a 4' fulcrum and the tongue at the 1' mark, I was reading 75 pounds on the scale!! That's 300 pounds of tongue weight!!!! My boat's weight is WAY too far forward. Any notion that the trailer is "just fine the way it is" strikes me as suddenly absurd. Putting the 35HP on the transom didn't have much effect on the tongue weight at all. My distribution is way off.

(This is how I weighed it...)

Image

Options:

- I can move the axle forward, but only by a few inches. Will this small movement make much of a difference? Not by my calculations.
- I could move the boat back, but only if I make new, longer bunks...because on a plywood hull, the transom shouldn't hang over the bunks.

But here's my real questions:

- Does it matter? The gross weight of the trailer & boat is way below the vehicle's limit (2009 GMC Acadia).....and the tongue weight (ratio notwithstanding) is also way below the vehicle's limit. Yes, my ratio balance is wrong, but the numbers themselves would seem to indicate there's no major problem here.

Before I start adjusting axles & making bunks, can I get a reality check? Am I ok as-is? Or do I need to be shifting balance?

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Bill Edmundson
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Re: Tongue weight / gross weight questions

Post by Bill Edmundson » Sun Apr 01, 2018 9:45 am

Mark

The tongue weight should be 10% of the total weight. For your drawing the scale will read 1/3 the tongue at 2', and 1/4 the tongue at 3'. This is at the ball. This may seem simple to you. But, others may be confused.

Bill
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Mark-NJ
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Re: Tongue weight / gross weight questions

Post by Mark-NJ » Sun Apr 01, 2018 11:09 am

Yeah I get the math.....and at the ball, I have 300lbs. (4' arm, ball at 1', scale at 3' from the ball.....reading 75 pounds.)

For my boat, 10% would be about 85-100 pounds. I would have to move the boat WAY back or the axle WAY forward, neither of which I can do to the required extremes.

I know the magic formula is 10-15%, but all my readings (gross & tongue) are well within the truck's capabilities, ratio notwithstanding. My question is: does it matter?

Too light of a tongue weight and the back will sway uncontrollably. But as I understand it, too much tongue weight is only about the towing vehicle's abilities, and I'm well within what the truck can do. So am I worrying about nothing?

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kens
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Re: Tongue weight / gross weight questions

Post by kens » Sun Apr 01, 2018 8:00 pm

how much weight does your tow vehicle react with that?
In other words, how much does your vehicle lower with that tongue weight?
If you say it already tows good, why bother.
I towed a uhaul one time, moving household goods, and it towed funny, I found it was light on the tongue. I rearranged the load for more on the tongue.
Oak is over rated, everything about it takes extra time; then it warps, splits or checks !!! :roll:

Mark-NJ
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Re: Tongue weight / gross weight questions

Post by Mark-NJ » Mon Apr 02, 2018 4:16 am

Driving the GMC Acadia with the trailer doesn't feel any different at all from driving without the trailer. The truck doesn't seem to even notice that there's a trailer attached. Nor is there any noticeable downward movement of the rear of the truck.

If there's a problem here, I can't find it. Yes, I realize that the tongue weight should ideally be 10-15%, but i'm asking "why?" I recognize that too little is very bad.......but being over 10-15%, as long as the numbers are within the capabilities of the truck, where's the problem?

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Bill Edmundson
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Re: Tongue weight / gross weight questions

Post by Bill Edmundson » Mon Apr 02, 2018 6:18 am

Mark

I think you're alright. I think the 10-15% guide line should read at least 10-15%.

Bill
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hoodman
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Re: Tongue weight / gross weight questions

Post by hoodman » Mon Apr 02, 2018 7:20 am

I think too much tongue weight is only a real problem if you go over the tongue weight rating of the vehicle. That's when you can the "tail wagging the dog" problems.
Matt

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Mark-NJ
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Re: Tongue weight / gross weight questions

Post by Mark-NJ » Sun Apr 08, 2018 5:44 am

Update:

I've never liked my trailer's bunks: too short, too narrow, and covered in that cheap "rat fur" carpeting that traps water against the hull. So I made new bunks: treated 2x6, capped with 3/4" vinyl, and they're longer, extending a foot further forward & 10" further aft. That allowed me to move the boat back, and with the engine mounted, tongue weight is now 185 lbs. A smidge over 15%, and I'm a lot happier now.

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Bill Edmundson
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Re: Tongue weight / gross weight questions

Post by Bill Edmundson » Sun Apr 08, 2018 6:40 am

Mark

I'm sure you feel better now. :wink:

Bill
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hoodman
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Re: Tongue weight / gross weight questions

Post by hoodman » Sun Apr 08, 2018 2:22 pm

That's gotta at least make it easier to hitch up.
Matt

Building a Geronimo......!
viewtopic.php?f=2&t=25139

PeterG
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Re: Tongue weight / gross weight questions

Post by PeterG » Sun Apr 08, 2018 6:00 pm

Nicely done, problem solved! I'm taking notes for my own project...
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Griffin's Law: Murphy was an optimist.

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billy c
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Re: Tongue weight / gross weight questions

Post by billy c » Mon Apr 09, 2018 6:50 am

Mark-
Much better! Now if you load the bed of the truck up with all your toys and stuff for the day, you will be towing at the optimal balance and braking performance of the tow vehicle
Billy
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