Trailer sway problems

[fokker416]

I have begun to experience some sway problems. I'm not sure if this is a new problem, or that I'm beginning to drive far and fast enough to discover an existing one. When I first bought the boat we went to a local lake, road speeds rarely went over 50mph on low traffic roads. Now we are driving out to the Gulf on busier roads at higher speeds. On our last trip we began to have some substantial sway until we slowed under 50. I can't reproduce the sway with speed or turns, it seems to happen ramdomly. On our last trip we had some sway problems on the way out, but none on the way home. I can't say for sure that passing traffic causes it. Any suggestions and/or solutions? I have a 1993 H23.5 with the original trailer with no modifications to it. The tires are pretty new (few months old), the balast is empty, I don't have an inordinate amount of gear. We have a Merc 9.9 motor.

 

[MrUnix]

Sounds like you might be loading the boat differently and causing the tongue weight to change (and therefore the trailering characteristics) between trips. Do you stow the outboard in the boat when trailering? Any other substantial weight that gets moved around?

Check your tongue weight next time you go out. It should be, depending on who you ask, somewhere around 10-15% of the total weight (of boat+trailer+gear).

Cheers,
Brad

 

[Dan H]

What you are using to pull the trailer with has a huge impact on trailer sway. Nothing short of a substantial truck is safe.
Envoys and the like really don't have a long enough wheel base to pull a 23' boat.
I have a 3/4 ton truck.

 

[Andy1237]

I thought I had read that sway is usually caused by too much tongue weight, bouncing or rocking is caused by too little tongue weight. Perhaps you loaded the boat further forward or more in the front of the boat?

 

[Sumner]

In my experience towing different trailers sway is usually a result of too little tongue weight and/or more weight at the ends of the towed trailer, especially at the rear of the trailer, in this case the boat. Kind of like the tail wagging the dog or a pendulum effect.

We pull with a 9.8 outboard on the back of the boat and also the dinghy outboard back there without problems, but also now have 2 axles and are pulling with a Suburban. When we first got the boat and the trailer had 1 axle and I tried to pull with our 4000+ lb. '83 Jeep Scrambler that has a long wheel base it was a disaster. Then we pulled the same trailer with the Suburban to Canada and back and it was ok, but not great, especially since the trailer didn't have brakes. Then I added the second axle with surge disc brakes and it....

.... towed like a dream to Florida and back, 5000 miles.

One thing I would try is to get more weight ahead of the axle. If that doesn't do it then I would put on a hitch...

http://www.harborfreight.com/8-in-1-adjustable-ball-mount-hitch-95991.html

....like above and try lowering the ball down a step at a time. If you find a ball height that works good then you could buy a hitch with that drop to it if you didn't want to leave the one above on. That will in effect transfer some weight forward and have hopefully other positive results. If that doesn't work and you have the outboard on the boat I'd take it off. One way or the other you need to fix it. As you are probably aware, you just aren't safe with it swaying.

Good luck and let us know what worked,

Sum

Our Endeavour 37

Our Trips to Utah, Idaho, Canada, Florida

Our MacGregor S Pages

Mac-Venture Links

 

[Benny17441]

Yes, check your tongue weight. Ball height will affect tongue weight. Ideally the desired tongue weight should be reached with the trailer rails parallel to level ground. That would denote that the weight of the load is correctly balanced on the trailer. Loads are seldom in perfect balance so adjustments can be made by lowering or raising the towing ball. An adjustable ball mount is used for this purpose. Raise the ball and your tongue weight decreases or lower the ball and tongue weight increases. It is also important that the tow vehicle's rear suspension be strong enough to support the the tongue weight. The rear suspension should not give more than a couple of inches and should definetily not bottom out. If the rear of the vehicle squats too much it will be prone to sway with reduced steering and braking performance. If the tongue weight is too light it will also sway. I would roughly guess that the weight of your rig is around 4,300 lbs and that your tongue weight should be around 450 lbs. Check you have the correct tongue weight and that the trailer and tow vehicle are fairly in balance and that should minimize any sway.

 

[woodster]

Yes, check your tongue weight. Ball height will affect tongue weight. Ideally the desired tongue weight should be reached with the trailer rails parallel to level ground. That would denote that the weight of the load is correctly balanced on the trailer. Loads are seldom in perfect balance so adjustments can be made by lowering or raising the towing ball. An adjustable ball mount is used for this purpose. Raise the ball and your tongue weight decreases or lower the ball and tongue weight increases. It is also important that the tow vehicle's rear suspension be strong enough to support the the tongue weight. The rear suspension should not give more than a couple of inches and should definetily not bottom out. If the rear of the vehicle squats too much it will be prone to sway with reduced steering and braking performance. If the tongue weight is too light it will also sway. I would roughly guess that the weight of your rig is around 4,300 lbs and that your tongue weight should be around 450 lbs. Check you have the correct tongue weight and that the trailer and tow vehicle are fairly in balance and that should minimize any sway.

Benny is correct about this......you may use between 300 and 450 lbs TW for that weight .....also check your tire pressure you may be low ...you will find that radial tires have a soft side wall and that will cause it some times as well so make the pressure a little higher and see how that works for you ....


regards

woody

 

[tkanzler]

Folks often report big improvements with little weight shift. That 9.9 doesn't weigh much - try moving it into the boat, or into the car even. Also make sure your tire pressure is up, possibly to maximum depending on their load rating and the actual tire load. Same with the tow vehicle - watch the tire pressure.

Some folks add a second axle, which is what the previous owners of my 26X did. I have no hint of sway, at any speed, and I only have about 200 lb of tongue weight with a 3500 lb (approx) boat and trailer. Since both axles are 3500 lb rated, the tires are loafing, and sidewall stiffness is effectively increased.

I do keep the speed down for the most part, though - too easy to get into trouble at high speeds, and the potential for disaster increases exponentially with speed.

 

[soling42]

I towed our old 240 with a single axle trailer just like yours for 1000's of miles with a Suburban and as was mentioned you'll need to (#1)weight the tongue, (#2)check your tires and (#3) have a good tow vehicle. Tail weight and low tire pressure on radial tires will be a killer. Bonafide trailer tires properly inflated with stout sidewalls are a must, but may still fall short for your issue. If it's not a tow vehicle that's too small, load imbalance or tire issues then it's just too much boat for a single axle trailer.

All that said I've pulled much bigger trailers my entire life and couldn't fix how terrible our 240 and its single axle trailer towed at speeds over 55mph until I bought our 260 with a dual axle trailer. Our 260 and its trailer is 30% heavier but far easier to tow. So do what you can, be safe and don't get in a hurry.

We've trailered our 260 all over your neck of the woods and loved it up there. Here's a pic from Silver Glen on the St johns at lake George. Have a good season. Mike

 

[Winkfish]

If you want to measure your tongue weight, if you have a trucking weigh station near you, they will let you weigh in if it's not busy.

 

[Sumner]

If you want to measure your tongue weight, if you have a trucking weigh station near you, they will let you weigh in if it's not busy.

I've used this method before...

http://www.etrailer.com/faq-trailertowtips.aspx

Sum

Our Endeavour 37

Our Trips to Utah, Idaho, Canada, Florida

Our MacGregor S Pages

Mac-Venture Links

 

[watercolors II]

Tongue weight is just a little light. Moving the boat forward just a couple inches will make a big difference. I’ve pulled by boat with a Ford Ranger, F150 and now a conversion van and no problems until last fall when I extended the trailer tongue 18 inches to keep from getting the carpet wet in the van.

The boat was still positioned over the axle the same, just the tongue is now 18 inches longer next to the tow vehicle. This lowered the weight on the trailer hitch by 26 lbs. I moved the boat forward 1 1/8 inches to recover 25 of those lbs. I used the bathroom scales at the coupler, 3300 lb boat and trailer with tongue weight of 315 lbs.

Check your trailer, after market trailers are built to handle many sizes of boats and what they do is the axles and springs are attached to a separate frame and then attached to the mainframe of the trailer. If you have this then just move the axle back, if you have boat mfg’s trailer then move the boat forward on the bunks. See photo of trailer with movable axles U-bolted to the main trailer frame.

 

[fokker416]

Thanks for all of the information. I've been offline for a bit, sorry I was slow to respond.

The load in the boat is a possibility. Sometimes when I load up to leave I leave the coolers at the very back (toss them in instead of moving them forward. I keep the standard 25qt under the seat, but I also have a large cooler that I keep in the front of the deck between where the main sheet attaches and where the "spine" in the deck ends. When it's full it usually has about a case of bottled water plus some other drinks, snacks, and a bag or two of ice. When I go home the coolers stay where they are when sailing. That could be a weight shift like what you guys are talking about.

I will double check tire pressure. I check them regularly, but not every trip. Yes, I will change that habit. The tires themselves are trailer tires made for this load.

I tow the boat with a Chevy 1500 Silverado V-6 so I don't think the towing vehicle is an issue.

I will also check the level of the trailer the next time we're hitched up. I think it's pretty flat but I'll take a close look. Is it better to have it angled up or down compared to the hitch?

I've always towed with the outboard attached, but I can put it in the truck bed when trailering it you guys think it will help.

My ultimate goal for this boat is to have a stable enough platform that I can take it up on the interstate for longer trips. The Keys immediately come to mind. If that means a tandem then, that's what I need.

What is an approximate cost to put on a second axle? Can you do it yourself without welding?

thanks again for the great help, keep the advice coming!

 

[MrUnix]

[...]
My ultimate goal for this boat is to have a stable enough platform that I can take it up on the interstate for longer trips. The Keys immediately come to mind. If that means a tandem then, that's what I need.

What is an approximate cost to put on a second axle? Can you do it yourself without welding?

Sounds like the weight distribution is your culprit.. sometimes just the smallest change can make a big difference. Best bet is to check your tongue weight and try to load the same way once you have it dialed in. You may find that you can tow just fine with the trailer as-is. Have not priced adding a second axle in a while, but they are pretty reasonable and you can get ones that bolt on without the need for any welding. A lot depends on how the existing axle is attached and what you have to work with.

The Keys are great for sailing.. my favorite route is to put in at Black Point Marina (Homestead/Florida City) and take the ICW south. Particularly spectacular at night cruising under Card Sound bridge. I generally get down as far as Tiki Bar in Islamorada, load up on Rum Runners and island music, then start the trip back north. Lots of little out of the way coves and bays that you can anchor in for the night. There are also a lot of hotels on the water that you can dock at if want a good shower and soft bed There is some good sailing south of that, but it gets pretty thin on scenery... Not much other than Marathon and Key West.

Cheers,
Brad

 

[Rick Webb]

Adding a Second Axle

I added a second axle using these:​

​

From here:

http://championtrailers.com/UNDERCARRIAGES.htm


I did not have to weld anything on but I did have to cut the old hangers off.​

 

[sinnettc]

I've marked the keel support on my trailer so I get the boat in the same place every time. It's amazing what a difference an inch can make.

 

[LordNelson]

Sway Bars

you can also add sway bars to the trailer hitch if you don't have them already. might be a good idea for a boat this side

 

[Bob 04 H260]

If you can get enough tongue weight it should tow fine without a second axle if the truck and trailer are not overloaded.

I think ball height is very important. I don't think it effects the static tongue weight but as speed goes up the air pressure under the hull will often be causing a sway problem. I like to keep the front of the boat down a bit, either by changing ball height or height of trailer bunks.

With the bow up a few degrees and an 18 wheeler goes by the wind will lift all weight off the ball, if the drivers window is open you will hear the hitch come up on the ball, this will often result in a little sway at this point. If the trailer speed increases further, tongue weight will continue to go down until sway begins.

With the bow down tongue weight increases with speed because of the air pressure on the foredeck. When a truck goes by there will be no sway.

This works with no change in staic tongue weight.

I think adding a second axle can cure this problem too, if you have ever tried lifting the tongue on a double axle trailer you will know why. I tow with a double axle trailer but keep the bow down on it and think it works better that way.

Bob