How do you avoid a crash like this?

[2biguns]

Last weekend, a good friend had a big boo boo while pulling his boat. He has (or at least had) a 28 foot Boston Whaler Walkabout that he had repowered with new 4 stroke 225 Yamaha long shaft engines. Total boat weight about 11,000 pounds.

While pulling the boat home (with 2002 Chevy 4WD 4 door 3/4 ton diesel w/ Allison tranny) on I-65, the boat started fishtailing while going down long straightaway. He tried speeding up, slowing down but nothing worked. The boat flipped, truck rolled and both are totalled (he's fine, a bit banged up but fine). Trailer was an All American tandem with surge brakes with at least a 12,000 pound capacity. Truck rated for 12,000 pounds.

This man is the most careful boater I know. He has probably logged more trailer miles than some folks have ever driven in their lifetimes (plus having logged a few thousand miles on a battleship during Vietnam). It now has me thinking about pulling the boat and what I would do if this happened to me.

What's the answer? How do you prevent fishtailing and if it starts, what's the best way out? We suspect that the new engines weighed a bit more than the old and it resulted in a bit less tongue weight on the truck.

Any thoughts?

[Digger]

"there but for the grace of God go I" comes to mind.

what a nightmare, that is horrible to hear...for what its worth, armchair quarterbacking here, but I think the proper course of action faced with fishtailing is slow down and stop, measure the tongue weight accurately (I posted a diagram a while back, search for tongue weight if interested). Get the tongue weight where it needs to be before attempting highway speed.

very glad to hear your friend is OK-

[Forrest]

Proper tounge weight is very important. Once the trailer starts severely fishtailing, it's almost impossible to get it under contol. I think the best thing to do is to back off slowly at the first sign of fishtailing, and drive slowly until you can get the tounge-weight problem resolved. Some trailers, but very few boat trailers, have electric brakes with an independent trailer brake control. In this case, if he could have applied the trailer brake only, I'm sure that would have brought it under contol. Yea, speeding up can bring it under control as well, but if it doesn't, your trailer could be fishtiling worse at a higher speed, which appears to be the situation that you discribed.

[RickSE]

This happened to me while pulling a 33ZX from L.A. to Flagstaff, all but the crash part. Very similar rig, long wheel base 3/4 ton pickup, 11-12,000 lbs on a tripple axle Myco trailer with surge brakes. I was being conservative but started down a big hill too fast, 60-65 MPH. The trailer began to wag, I tried the truck brakes but it just got worst. At some point I decided to just ride it out. I certainly learned my lesson and backed off on the down hill runs from then on. As the others stated tounge weight is very important, a rig with sufficient tounge weight will resist wagging. In addition, keep the speeds down on downhill runs.

Rigs pulling trailers typically wag becaues with light tounge weight the ass heavy trailer begins to push on the tow rig. A heavy trailer (heavier than the tow rig) will want to roll faster than the tow rig when going down hill. When this happens the trailer trys to push around the tow rig and begins to pivot on it's own wheels. You need the heavy tounge weight to keep the tow rig's rear suspension and tires firmly seated on the pavement to maintain sufficient traction and control.

[2biguns]

Great thoughts. I talked to him again--he tried everything. First he braked, downshifted the truck, sped up, all to no avail. His old engines were 2 stroke Yamaha 200's and I'm sure he had the tongue weight perfect. I'm really surprised that upgrading engines would have this dramatic an effect on tongue weight.

My 29 is, if anything, too far forward and I pull it with a Ford F250 PSD and have never had any swaying. I'm going to find Digger's formula and do my calculating before towing on the interstate again.

[Digger]

yet another 2 cents. I am a firm believer in a dually tow vehicle for heavy boats. The dually doesn't gain me anything as far as payload goes over a single rear wheel, but the intangible statistic: "towing stability" is the payoff. The duals help dampen out any sway very quickly. My rig (F350 dually powerstroke/triple axle slideon/810 lbs tongue weight) allows me to go as fast as I want with no sway or fishtail. Safety considerations, of course, dictate max allowable speed. However, on the open highway, little traffic, going down a hill and a big hill coming up I'll basically get that momentum going as much as I can, up to 80 mph, to help carry the hill.

[Jamesbon]

My pop experienced the same thing due to too little tongue weight. You have to move the boat forward on the trailer.

I hope he was fully covered :rolleyes:

[2biguns]

He's my insurance agent so I'm sure he had coverage. Luckily he had removed all the electronics prior to taking the boat for repower. The only thing left is the steering wheel.

Digger--I've sung the praises of my Ford to him but one of his best customers is our local Chevy dealership. His nephew has a '01 GMC 4 door dually 1 ton that I think he may consider but it's heck trying to park and get around town.

The sad part is that he had a 1 week-long boat trip to the Bahamas planned with a large group. He may still go and take his 18 foot Whaler as alternate transportation. He's done the trip before in the "Baby Whaler" and is salty enough to handle it.

[CDMA]

I have one of them. That 18 Whaler Outrage is SOME boat. It goes through anything. I have over 2000+ hours on it in about 10 years and it is a tank.

Chris

[Bob]

A great way to stop a fishtailing trailer is with the use of electric brakes on the trailer. This will not compensate for not enough tongue weight but putting on the trailer brakes without putting on the tow vehicle brake will stabilize the rig. It also works if an 18 wheeler blows by you on the interstate.

[MOP]

Maybe I scrolled through a little to fast but I did not see any mention of anti sway hitches. We use to install them on alot of customers boat, so you do not need as much tounge wieght which keeps the front end of the tow vehicle down where it belongs and not on the light side. Ever have the front slip in a turn in the rain? A few dollars more they are well worth it if you tow heavy.

[Woodsy]

Just my .02 worth

If it were just a tongue weight problem, accelerating should have pulled the trailer back in in line. I would look to a trailer failure of some sort. Maybe an axle broke, or one of the bolts that hold the axle square to the trailer maybe loosened up. If this guy was the careful person 2Biguns made him out to be, and he had an excessively light tongue weight, he probably would have noticed it. To cause a fishtailing event like that, with that kind of energy release, he would have to have almost no weight on the tongue whatsoever. I think I would look to some sort of mechanical failure.

Woodsy

PS: Glad he is ok!

[Bryan Tuvell 33ZX]

Wow what a story, and lets not forget tire inflation, I learned on a NEW trailer last November..." yep all tires at 50PSI, sway, sway...
NOT! Checked them hot and they were at 35PSI!

You almost need to know as much about your trailer and tow rig as you do about boating etc....
I sure have learned allot here, great thread...
And thanks MPOODLE for all your help!
Bryan

[Formula Jr]

The center of gravity was to high for the suspension (sp) system of the trailer to deal with.
Why trailers do not usually have shocks, just baffels me......Even travel trailers don't usually have them.

Or.......
The road may also have been very troughed. The three rigg guys will speak to this. If a wheel is pulling on a rise it will do so till it hits a crest, then the trailer will fall back into the trough cause it wants to run inline with the tow car. But the inertia will toss it back on to the other rise. And the whole cycle will repeat. There isn't a cure. You just slow WAY down and look for alternative routes. Obviously I don't have as much experience as your friend, towing stuff and all, but road conditions are a factor. :D

[steve simon]

Balance is everything!! Who set up this trailer? These new 4 stroke engines weigh approx 145lbs more than carb or efi engines. Balance is the key. Good luck-
Steve Simon

[RickR]

I agree with Bryan about tire inflation.

Tow vehicle tire need to be correctly inflated also.

Stiffer sidewalls on the trailer and tow vehicle help also. My truck uses load range E 10 ply tires and 8% tongue weight and I have NO sway problems :D