trailer sway

[dmebaum23]

on my single axle trailer with the boat full of gas and at speeds around 65mph the trailer tends to sway back and forth. It can turn into a dangerous situation if i dont watch what im doing. any ideas on how to fix besides throwin the cooler full of beverages in the bow to give the trailer some extra tongue wieght, or modifing the trailer?
Thanks,
Drew

[chpthril]

Trailer sway is usually a result of too much or not enough tongue weight. With the boat hitched up to the tow vehicle, does it sit close to level? in other words, is the distance from the ground to the trailer frame rail the same behind the axle near end of the trailer as it is near the coupler?

Start with that, then we can go from there.

[Ewok]

I guess too light in the bow, meaning not enough tongue weight. Load the boat up like you normally do, get the trailer level and follow these instructions to determine your tongue weight. You should load the boat so the tongue weight is about 10% of the total weight of the boat and trailer (and all the other stuff in the boat).

For heavier tongue weights, place a household scale and a brick that's as thick as the scale 3 feet apart as shown. Set a length of pipe on each and rest a beam across the pipes. Re-zero the scale to correct for the weight of the beam and pie. Securely block the trailer wheels. Rest the trailer coupler on the beam , 1 foot from the brick and 2 feet from the scale. To obtain tongue weight, multiply the scale reading by 3. For even heavier weights, place the scale and brick 4 feet apart, rest the coupler on the beam 3 feet from the scale and multiply scale reading by 4.

[dmebaum23]

last saturday the tongue wouldnt go on the ball right so i just picked up the tongue it was pretty heavy, i would guess 250 lbs or so.. the boat does sit level hooked up, and it does give my half ton gmc an approx 1 inch squat.

Thanks
Drew

[somebodyelse5]

I guess too light in the bow, meaning not enough tongue weight. Load the boat up like you normally do, get the trailer level and follow these instructions to determine your tongue weight. You should load the boat so the tongue weight is about 10% of the total weight of the boat and trailer (and all the other stuff in the boat).

For heavier tongue weights, place a household scale and a brick that's as thick as the scale 3 feet apart as shown. Set a length of pipe on each and rest a beam across the pipes. Re-zero the scale to correct for the weight of the beam and pie. Securely block the trailer wheels. Rest the trailer coupler on the beam , 1 foot from the brick and 2 feet from the scale. To obtain tongue weight, multiply the scale reading by 3. For even heavier weights, place the scale and brick 4 feet apart, rest the coupler on the beam 3 feet from the scale and multiply scale reading by 4.

thats clever, its the moment about the brick! im doing this stuff in my statics class haha...

[NICKYPOO]

You should be able to move the winch post forward or backward to adjust the tongue weight. In your case, I would say try moving it forward to give yourself more tongue weight.

[Ewok]

thats clever, its the moment about the brick! im doing this stuff in my statics class haha...

Sometimes I'm surprised how much I use the basics from algebra, geometry, static and dynamics in real world situations. And knots, I learned a lot about knots in boy scouts and still use it today.

[G-MONEY]

Slow down when you tow

[somebodyelse5]

Sometimes I'm surprised how much I use the basics from algebra, geometry, static and dynamics in real world situations. And knots, I learned a lot about knots in boy scouts and still use it today.

its crazy how much it all applies in everyday life....now, how calc 3 applies im not entirely sure haha .

[chadster2]

Well……. the area under the graph is nice to know over time. Like medications or finances or heat loss but then rule of thumb counts for something too. For everything I've seen, the unaccounted for losses make the equations unrealistic anyway.

its crazy how much it all applies in everyday life....now, how calc 3 applies im not entirely sure haha .

[chadster2]

I'd say try putting some extra weight in different places and go for a test drive.... 300-400 lbs (1 fat sac and maybe full vs. empty gas tank)

[dmebaum23]

65 mph is about as slow as i can can really go...
and i even coming home with an empty gas tank there is sway but its a lot less than full.

[AdaminMN]

What trailer do you have?

[somebodyelse5]

Well……. the area under the graph is nice to know over time. Like medications or finances or heat loss but then rule of thumb counts for something too. For everything I've seen, the unaccounted for losses make the equations unrealistic anyway.

yup. as well as all the equations in physics... ignoring friction, wind resistance, ect, makes alot of that type of stuff not apply. but alot of the stuff from statics, basic circuit analysis, most of the actual engineering courses pretty much, apply in a bunch of different ways. thermodynamics, mechanics of materials, Dif EQ, and Dynamics next semester haha

ok back on topic haha.

[NICKYPOO]

yup. as well as all the equations in physics... ignoring friction, wind resistance, ect, makes alot of that type of stuff not apply. but alot of the stuff from statics, basic circuit analysis, most of the actual engineering courses pretty much, apply in a bunch of different ways. thermodynamics, mechanics of materials, Dif EQ, and Dynamics next semester haha

You might find this guy interesting, Mr. Pete Law.

"Peter worked at Area 51 as a Lockheed thermodynamics engineer associated with A-12 and the U-2 in Burbank and Palmdale. His career included the M-21, D-21, YF-12A, SR-71, F-117A, Have Blue, and Senior High , all requiring boots on the ground at Groom Lake. He worked for Lockheed as an engineer for 42.5 years, 40 years of it being at the Skunk Works which included his being the thermodynamics department manager for final 20 years. Peter retired in 2001."

This is what you get when you ask him a simple question, which I have very fortunately been able to do. Truly an amazing guy to talk to.
http://www.enginehistory.org/Convent...te/Cooling.pdf