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General Forestry => General Board => Topic started by: DouginUtah on May 26, 2012, 12:20:00 AM

Title: Recovering from Fishtailing
Post by: DouginUtah on May 26, 2012, 12:20:00 AM

I got trapped in a traffic jam this afternoon on the I-15 freeway. A 2500 Chevy extended cab pulling a large toy-hauler started to fishtail and ended up with the toy-hauler on it's side and the truck flipped several times and the roof pretty much ended up crushed down to the seat tops. Traffic was moving right along at 65+ MPH. Life-threatening injuries.

In the comments (on KSL.com) a guy said when you start to fishtail step on the gas as the trailer is trying to pass you. I don't believe that, but I thought I would ask if anyone can state authoritatively what the best plan of action is when fishtailing starts.
Title: Re: Recovering from Fishtailing
Post by: Ianab on May 26, 2012, 12:46:48 AM
Using a bit of gas will usually straighten you out...

This of course depends on you having some place to go, without slowing down.

I've had to use it once, towing a friends race car on a trailer. Coming down a long, steep, but straight hill. Let the speed build up a little more than I should, and lightly touched the brakes. Trailer gave the first signs of starting to fishtail, so I got back on the gas and it straightened up instantly.

Luckily there was a big sweeping corner at the bottom of the hill that we cruised around at about 90mph, then just coasted the speed off on the flat.

If we had HAD to stop, things would have gotten VERY exciting.

Ian
Title: Re: Recovering from Fishtailing
Post by: DouginUtah on May 26, 2012, 12:49:41 AM
 

 (https://forestryforum.com/gallery/albums/userpics/10332/chevy2500rollover.jpg)
Title: Re: Recovering from Fishtailing
Post by: beenthere on May 26, 2012, 01:14:56 AM
I'd agree with that advice.
And thankfully a semi truck driver knew how to do that, or I'd a been wiped off a slippery road when helping with a car accident. Around a curve came the semi and as he slowed (seeing lights in the ditch) the trailer started coming around him. He poured the gas to it and pulled the rig straight again.

Is really the only alternative one has to save it.
Title: Re: Recovering from Fishtailing
Post by: ely on May 26, 2012, 01:42:57 AM
x3
Title: Re: Recovering from Fishtailing
Post by: bill m on May 26, 2012, 07:58:23 AM
You can also manually activate the trailer brakes with the brake controller while keeping light pressure on the gas pedal.
Title: Re: Recovering from Fishtailing
Post by: Magicman on May 26, 2012, 08:08:35 AM
I realize this is about "recovering", but "prevention" is so easily overlooked.  A tail heavy trailer is an accident waiting to happen.  That toy hauler probably had an ATV strapped in it's rear end.

I wonder what the new trucks with the computer controlled anti-sway, etc. gizmos will do.  Maybe just allow you to go faster and then really have a wreck.   :-\
Title: Re: Recovering from Fishtailing
Post by: Dan_Shade on May 26, 2012, 08:42:24 AM
giving it gas, or activating the trailer brakes can help.  my brake controller has a button that I can hit to engage the trailer brake without the truck brakes.

proper tongue weight is critical for safe towing, but the most important safety device lies between one's ears.
Title: Re: Recovering from Fishtailing
Post by: Corley5 on May 26, 2012, 09:09:05 AM
An old log truck driver told me years ago when we were talking about trailers swaying and jack knifing to "drop a gear and give it he**".  That would straighten it out.  :) :)
Title: Re: Recovering from Fishtailing
Post by: scsmith42 on May 26, 2012, 09:19:05 AM
Quote from: Dan_Shade on May 26, 2012, 08:42:24 AM
giving it gas, or activating the trailer brakes can help.  my brake controller has a button that I can hit to engage the trailer brake without the truck brakes.

proper tongue weight is critical for safe towing, but the most important safety device lies between one's ears.

+1000 on all counts.
Title: Re: Recovering from Fishtailing
Post by: Qweaver on May 26, 2012, 11:26:28 PM
High polar moment of inertia coupled with springs rhythmically  loading and unloading  spell bad times for the driver.  I've usually just slowly let the rig slow down and that has always worked for me.    But I always try to catch it before it gets bad.  I've never had a problem with a properly loaded trailer.  My wife got a double trailer pull totally sideway after falling asleep and was able to recover it.  But the trailers were properly loaded and she drove race cars sideways for years.  Makes a difference knowing  that just because you are sideways does not mean that you are out of control.
Title: Re: Recovering from Fishtailing
Post by: Polly on May 27, 2012, 03:30:15 PM
 :) :)   i probly have seen over a half dozen car pickup pulling trailer accidents over the years ,like the gentelman above so accurately stated ,load your trailer heavy enough in the front so you  see can the rear end of the veichle it is hooked to start to squate that way the towing vehicle is in control ,otherwise the trailer is , kinda like the tail wagging the dog  ::) ::)
Title: Re: Recovering from Fishtailing
Post by: Sprucegum on May 27, 2012, 03:54:11 PM
First-time trailer towers should also be told to quit looking in the mirror. They see the trailer sway a bit and over correct - it escalates from there.

I watched a young fellow towing a heavy load of drill stems behind a half-ton. He started fishtailing on loose gravel. The trailer eventually chased him in the ditch where it tipped over. Everything was almost at a stand-still when the torque on the hitch flipped the truck on its side. The young fellow popped out of the side window and landed in the middle of the road like a cork out of a pop gun  :D  :D  He had a good lesson that day  ;)
Title: Re: Recovering from Fishtailing
Post by: SPIKER on May 28, 2012, 10:52:19 AM
Came close to having one fish tail issue towing a independent suspension car on a dolly behind my F150.   Front wheels were on ground (rear wheel t-bird) hit a bridge in corner where it bottomed out suspension in car and caused it to twist about a lot little gas and kept the turn going came out good...

mark
Title: Re: Recovering from Fishtailing
Post by: Polly on May 29, 2012, 08:05:07 AM
 :( :( the last one i seen was on i-75 south of atlanta , traffic backed up several miles , when i finally got to the accident a mina van towing a home made trailer with a full sixe pick up on the trailer was off the road over in the area between the north and south lanes the trailer on its side pick up still hanging on mina- van still on its feet ,kinda felt sorry for the fellow trying to save himself a dime , probly cost a grand by the time towing co and georga police got done with him  :( :( :( 8)
Title: Re: Recovering from Fishtailing
Post by: Deedee on June 25, 2019, 03:56:40 PM
I know this is an older post but it is the only info I could find on fishtailing. We came off a bridge found downhill doing 70 when the trailer started fishtailing big time immediately. No warning. My 16 year old was driving and did an excellent job counter steering gently and getting off the gas. We thought we were going to roll. It was a very close call. Once we stopped and caught our breath we checked the trailer and saw that a tire blew. Rear driver side, back tire from a double axel. Anyway, the weight was distributed well, heavier in front, etc. my question would hitting the trailer breaks have slowed it down faster? Even with a blown tire or would it have send us rolling? We tried speeding up but it made it worse immediately, probably due to the blown tire. Scariest experience of our lives and hope we never have to experience it again but should it happen again we want to be better prepared. Any help is greatly appreciated. Thank you. 
Title: Re: Recovering from Fishtailing
Post by: barbender on June 25, 2019, 05:49:29 PM
I always hit the trailer brakes in that situation, and counters all of the forces that are in play.
Title: Re: Recovering from Fishtailing
Post by: WV Sawmiller on June 25, 2019, 06:23:30 PM
   I have never had it happen on the highway but I have often had it happen with my ATV and utility trailer, cart, Logging Arch or even when just dragging a log down my hillsides Fortunately there is generally nothing else in the area that prevents me from being able to give it the gas to get the prime mover and the load in line again then slow down gently under more control.
Title: Re: Recovering from Fishtailing
Post by: Brad_bb on June 25, 2019, 07:33:49 PM
I had a uhaul trailer with sides I rented once but the load I put in it ended up being odd shaped.  There wasn't a good way to load it to know you had the weight distribution right.  well I did 45mph all the way home (an  hour and a half at the speed limit) via back roads and it took awhile.  It tried to start fishtailing on my a couple times and accelerating got it out of the resonance.  That is what happens with fishtailing, you over correct and it grows til you can't control it.  If you brake, it gets worse.  Accelerating will help pull you out of it, but then you are going faster and you have to be very careful to let it slow down without starting a resonance again.  I had that happen on my regular trailer, though not nearly as bad once with another odd load.  I don't ever want that situation again.  This is why you have to front load the trailer to get 60% or so of the weight in front of the axle.  Remember, it's not just the weight, it's also the distance from the axle.  You want the torque around the axle to be 60% in front.  Torque is Weight x Distance from axle.  For example, if you have 100lbs 4ft in front of the axle, and 50lbs 8ft behind the axle, then that is a 50:50 loading, because 100x4=400ft-lbs, and 50x8=400ft-lbs.  So if you shift the 100lb load forward another 2ft, then 100x6=600 ft-lbs.  That is a better loading.  If you're hauling lumber, since it's weight is equal along it's length, then you need 60 percent of it's length ahead of the rear axle.
Title: Re: Recovering from Fishtailing
Post by: Sanford mizer on June 25, 2019, 07:43:44 PM
When in debut Throttle out  8)
Title: Re: Recovering from Fishtailing
Post by: Bruno of NH on June 25, 2019, 07:55:12 PM
I just reach down and hit the trailer brake a bit till it straightens out.
I had one dump trailer that never pulled well no matter how you loaded it.
Title: Re: Recovering from Fishtailing
Post by: samandothers on June 26, 2019, 11:21:56 AM
I too understood that trailer brakes applied manually would help.  I have a neighbor that stated he would get on the brakes of the vehicle and the accelerator.  He indicated this would apply trailer brakes and a pull from the vehicle to correct the fishtail.  I have never tried this.  Do you have a anti sway bar on the hitch, assume it is tag along?  A sway bar helped my camper pulling experience.
Title: Re: Recovering from Fishtailing
Post by: Ed_K on June 26, 2019, 04:10:22 PM
 Haven't driven TTs for yrs do they still have a hand brake on the steering wheel pole?
Title: Re: Recovering from Fishtailing
Post by: clww on June 26, 2019, 07:31:02 PM
Quote from: Ed_K on June 26, 2019, 04:10:22 PM
Haven't driven TTs for yrs do they still have a hand brake on the steering wheel pole?
Yes, Ed. Most companies still have the "Johnson Bar" or "Trolley Bar" for operation of the trailer brakes.
Title: Re: Recovering from Fishtailing
Post by: samandothers on June 26, 2019, 08:18:36 PM
Brake controller I installed on my previous  truck, 2004 GMC 2500HD, was made like a CB microphone and the cord plugged into an under dash control.  The hand held device that stayed on the console allowed you to adjust the brakes and had a switch on the side like a microphone key that you could squeeze if need to manually apply brakes.  The truck I have now has a factory brake controller but has a slide switch on the lower dash you can apply brakes with.