24' Pontoon with sever sway, why?

Big O_24

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Sep 2, 2010
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I have a 24' pontoon that I trailer to different locations and it sways really bad on smooth flat hwy's, adjusted the pontoon further forward for more tongue weight, helped slightly.

Trailer- 24' under deck type trailer, dual axle. Purchased the trailer seperate from the pontoon. Oh yah, has a 115HP Merc on for a motor, lot's of back end weight.

Need advise.

Making people nervous and using up a whole lot of road. :)
 

jtmarten

Master Chief Petty Officer
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Aug 2, 2004
Messages
825
Re: 24' Pontoon with sever sway, why?

You need more tongue weight. Move it forward, spare tire, etc.
 

jeeperman

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Re: 24' Pontoon with sever sway, why?

One thing to do is to have the bow of the pontoon angling down some when it is hitched to your tow vehicle.

Otherwise the faster you go the more air you might be trying to pack in under the deck.
Which will make the tongue weight less.

Like a kite.

And welcome to the fray.
 

dockwrecker

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Mar 10, 2006
Messages
1,392
Re: 24' Pontoon with sever sway, why?

The tongue weight is the first place to check. Also give a look at the spring shackle bushings. Are you using st type trailer tires? If all of the above is good, an equalizer type hitch may be in order.
 

jfadool

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May 25, 2009
Messages
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Re: 24' Pontoon with sever sway, why?

Lack of tongue weight is most likely the cause. You could add anti-sway bars, but make sure that you have enough weight on the hitch first.
 

H20Rat

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Mar 8, 2009
Messages
5,199
Re: 24' Pontoon with sever sway, why?

One thing to do is to have the bow of the pontoon angling down some when it is hitched to your tow vehicle.

Otherwise the faster you go the more air you might be trying to pack in under the deck.
Which will make the tongue weight less.

Like a kite.

And welcome to the fray.

most pontoon trailers don't have a walking axle/bogey design, if you aren't perfectly level you are going to either have an unusually large artificial tongue weight, or a lot less. Angling it down below level will basically give you the same affect as moving the axle forward, reducing tongue weight. More or less if it isn't level you are putting most of your load on one axle only.

On my pontoon, the only way to get the hitch to touch the ground is to stand on it. The hitch will hover a couple inches off the ground with zero tongue weight. But, when at vehicle towbar height, it has 200+ pounds of tongue weight.


With all that said, is your trailer as level as possible when connected to the tow vehicle? If it isn't, that will most certainly cause some fun issues.
 

jeeperman

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Aug 2, 2001
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Re: 24' Pontoon with sever sway, why?

most pontoon trailers don't have a walking axle/bogey design, if you aren't perfectly level you are going to either have an unusually large artificial tongue weight, or a lot less. Angling it down below level will basically give you the same affect as moving the axle forward, reducing tongue weight. More or less if it isn't level you are putting most of your load on one axle only.

On my pontoon, the only way to get the hitch to touch the ground is to stand on it. The hitch will hover a couple inches off the ground with zero tongue weight. But, when at vehicle towbar height, it has 200+ pounds of tongue weight.


With all that said, is your trailer as level as possible when connected to the tow vehicle? If it isn't, that will most certainly cause some fun issues.

After second thought, I can agree that angling the pontoon and trailer downward could also result in a lighter tongue weight at highway speeds. Via the airflow over the top and pushing down on the stern much like a rear spoiler on a racecar. Level is better than being nose high.

Is this trailer also one of those scissor lift type, under the deck trailers? Is it built for highway use? A lot of those type trailers were/are built for use around marinas and such just to pull pontoons from the water to the storage yard and nothing more.
 

matt1982

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Aug 31, 2010
Messages
14
Re: 24' Pontoon with sever sway, why?

either get more drop at the tongue so you are angled down slightly past level at the front ( nose down) or take your trailer to a fab shop and have them move the axles back a few inches... both will help, i recommend having someone who builds trailers take a look to make sure yours is adequately designed for what you are hauling
 

Big O_24

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Sep 2, 2010
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Re: 24' Pontoon with sever sway, why?

Gents, thanks for all the recommendations. I will make a list and work through them to resolve my problem.
 

Bondo

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Messages
70,468
Re: 24' Pontoon with sever sway, why?

Ayuh,.... Tongue weight should be 7% to 15% of the gross weight....
Also,...
Measure the alignment of the wheels to the coupler hitch...
 

rwidman

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May 27, 2004
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1,396
Re: 24' Pontoon with sever sway, why?

Ayuh,.... Tongue weight should be 7% to 15% of the gross weight.......

Well, I would say more like 7% to 10%, but that's from reading the trailer manufacturer's recommendations. I don't know if a pontoon boat would be different.

The only way to know is to have the boat and trailer weighed on a scale. Look in the phone book. Once you know the weight of the rig, move the boat or axles until you have the correct tongue weight.

The trailer should be level when connected to the tow vehicle, not angled up or down. This is especially important with tandem axle trailers.

One other thing - What are you towing it with? Not a Honda Civic, I hope? Is the tow vehicle rated for and capable of towing the boat and trailer?
 

Mr Crabbs

Petty Officer 1st Class
Joined
May 28, 2010
Messages
267
Re: 24' Pontoon with sever sway, why?

When we bought our pontoon I asked the tech what height my hitch needed to be and was told 19" for my boat and trailer. It's a single axle and we've been up and down country roads and I-71 with no issues. It actually sways less than my PUP did.
 
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