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Sway issues 2007 Avalanche towing boat.

chetcpo

Full Member
Joined
Jan 15, 2015
Messages
12
I towed my 2012 Chaparral H20 19 Sport to the lake this summer and it was a harrowing experience.  For whatever reason when I went over 60mph I would develop this sway that would amplify and the only way to get out of it was to floor it or coast till it quit, braking seemed to make it amplify.  Anyone know what I'm talking about?  The boat isn't really heavy at around 3000# and the Avalanche is supposed to tow up to 8000# so I'm baffled at what the problem is.  Any ideas?
 
You need the sway control added to your hitch. I had the same problem towing an off road rig and it was much better when I moved the rig forward on the trailer. It was rock solid with the sway control though. Not very expensive. Do you have a load leveling hitch?
 
raiderron said:
You need the sway control added to your hitch. I had the same problem towing an off road rig and it was much better when I moved the rig forward on the trailer. It was rock solid with the sway control though. Not very expensive. Do you have a load leveling hitch?

No, just a standard hitch as far as I can tell. This is a picture of my model boat and trailer. Not mine, but identical.  That long hitch doesn't look compatible with what I saw when I googled "load leveling hitch".   The tongue on this thing is so long I can pick up the front of the trailer with one hand when it's not hitched up. The boat is almost perfectly balanced over the trailer wheels. I wonder if my trailer wheels are out of alignment.
digi48424657_l.jpg
 
What's the tongue weight?

 
But looking at the pictures of the sway control it connects to the trailer sides after the "spit" of the rails.  On this trailer (pictured above) that's a very long ways from the actual hitch. Like over ten feet.
 
10 to 15% tongue weight is a good rule-of-thumb.

Too light a tongue weight on a trailer like that will cause it to sway.

If that trailer is a total of 3000 lbs then the tongue needs to weigh between 300 and 450 lbs.
 
http://www.seasense.com/index.php?option=com_content&task=view&id=86&Itemid=204
 
EXT4ME said:
10 to 15% tongue weight is a good rule-of-thumb.

Too light a tongue weight on a trailer like that will cause it to sway.

If that trailer is a total of 3000 lbs then the tongue needs to weigh between 300 and 450 lbs.
Well it's way lighter than that. 
 
Looking at the picture you need to lower the front of the trailer, my guess is air is getting under the bow and causing it to lift and transferring weight to the back wheels of the trailer.

Try getting a drop hitch, just a 2 or 3 inch should help you.

image_13320.jpg


 
Unfortunately a single axle trail is more prone to sway..

It does sound like you need more weight on the tongue although hard to see in the picture it looks like the boat is sitting to far back on the guides (red arrow at rear), it should be just over the end of the guide (blue arrow at rear). If the stop at the front (red arrow front) is bolted on you can move it forward (blue arrow front) so the rear of the transom is just over the edge of the carpeted guide. If it's welded on then it would have to be cut off and re-welded. Take it to the boat shop you bought it or to a good marine shop and have them look at it. The boat looks to be an IO so all the weight is in the rear of the boat

This will put more weight forward and may help with the sway. You can also add a sway control device, their only about $50 if you don't have surge brakes, hard to tell in the picture.

Also if the boat is hanging over the carpet guide it can cause a hook to develop in the bottom of the boat just ahead of the transom and that is not good for performance.


 

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I agree with Randy.

At first glance, I could see the boat is too far back on the trailer.

I have been towing boats with single axle trailers for close to 40 years without ever using any kind of fancy device to control sway.

Get the weight forward onto the hitch and this trailer will settle down nicely.

Too much weight on the hitch can cause it's own set of problems but your are not even close to being in that kind of situation.

If you can get that 10-15% of the total trailer weight onto the tongue and the frame of the trailer and the truck are perfectly level, then you will be golden.

Most likely, the only thing you will have to buy is a trailer jack on the front of the trailer if you do not already have one and a different drop receiver hitch to keep everything level once mounted.

Someone just didn't set up that boat properly on the trailer.

There is no way you should be able to just pick up the tongue without using a jack and move it around freely.
 
05snopro440 said:
You guys realize that's not his boat and trailer, just the same model?

Not that the advice isn't good, but dolling out advice based on that picture might not be that applicable.

This!

Also you shouldn't be getting much if any sway with a boat that small.  I have a 22ft wakeboarding boat that weighs significantly more than your boat and I get 0 sway unless it is windy.  I know this isn't very helpful info just reconfirming your thoughts that this isn't right.  How old are your trailer tires?  Do you move your boat around in the winter so they don't get flat spots?
 
05snopro440 said:
You guys realize that's not his boat and trailer, just the same model?

Not that the advice isn't good, but dolling out advice based on that picture might not be that applicable.

Mine is just like that, same trailer and everything and it sits in the same position.  When it's loaded and cranked all the way up to the stop it sits that far back.  I guess Chaparral doesn't give much thought to trailering these small boats.  (trailer that comes with the boat is made by Karavan but has Chap logos on it)
It does have brakes on the trailer which makes it a pain in the ass because every time I try to back it up the brakes lock up and I have to get out and insert this little key thingy to keep the brakes from engaging. I'll try to load more stuff in the front of the boat next time and see how that goes.  
Thanks guys for all of the helpful information!
 
Also you shouldn't be getting much if any sway with a boat that small.  I have a 22ft wakeboarding boat that weighs significantly more than your boat and I get 0 sway unless it is windy.  I know this isn't very helpful info just reconfirming your thoughts that this isn't right.  How old are your trailer tires?  Do you move your boat around in the winter so they don't get flat spots?

It's a 2012 and I've only towed it a few hundred miles and it sits in a rack facility 90 % of the year so the trailer gets very little use.
 
I realize that's not his boat I was just pointing out the set up on that boat was not right and if his tongue weight is low he might have the same situation and should check it.

Randy
 
I'll throw in my 2 cents.

First of all, I think most of the time the 10 to 15% rule needs to be thrown out when towing boats.  Any good boat manufacturer designs their trailer to be a perfect fit to the boat, regardless of the weighting.  I have a boat that weights about 6000lbs on the trailer and the hitch weight was 340lbs (I measured it).  It tows like a dream.

Secondly, single axle trailers are prone to sway.  That is simply a matter of fact and it sucks.  A lot of this can be negated because the boat is highly aerodynamic, as opposed to a TT or a car hauler.  This aerodynamic effect is another reason why I don't buy the 10 to 15% rule.

Now in your case, it sounds like the boat manufacturer did a bad job matching the trailer to the boat.  So that sucks. I think your best plan of action is to get a sway controller designed for a straight hitch and move as much weight forward as you can.  (towing with less fuel in it could also help).

Pole%20Tongue.jpg

http://www.hitchsource.com/equalizer-pole-tongue-adapter-p-27444.html

You don't want the weight distribution, just the sway component.  Weight distribution will be the opposite of what you want.

I'd also recommend going to a dedicated shop for this and asking what they would do.  I'm sure they see this stuff all the time.

 
I stand behind what I said.

http://www.gmc.com/trailering-towing/tongue-weight.html

http://www.gmc.com/boat-trailering-safety.html

Best of luck to you.
 
chetcpo said:
Mine is just like that, same trailer and everything and it sits in the same position.  When it's loaded and cranked all the way up to the stop it sits that far back.  I guess Chaparral doesn't give much thought to trailering these small boats.  (trailer that comes with the boat is made by Karavan but has Chap logos on it)
It does have brakes on the trailer which makes it a pain in the ass because every time I try to back it up the brakes lock up and I have to get out and insert this little key thingy to keep the brakes from engaging. I'll try to load more stuff in the front of the boat next time and see how that goes. 
Thanks guys for all of the helpful information!

Are they surge brakes or electric?
 
chetcpo said:
Mine is just like that, same trailer and everything and it sits in the same position.  When it's loaded and cranked all the way up to the stop it sits that far back.  I guess Chaparral doesn't give much thought to trailering these small boats.  (trailer that comes with the boat is made by Karavan but has Chap logos on it)
It does have brakes on the trailer which makes it a pain in the ass because every time I try to back it up the brakes lock up and I have to get out and insert this little key thingy to keep the brakes from engaging. I'll try to load more stuff in the front of the boat next time and see how that goes.  
Thanks guys for all of the helpful information!


The first thing I would do is get the boat sitting on the trailer correctly before doing/buying anything and then take it for a test drive and see how it performs.
 
I like the idea of the drop hitch to get the weight more forward and the sway control I suggested is still my choice. It would not connect 10' back. Like I said in my earlier post, the weight is too far back and contributing to the sway. Especially with the single axle trailer.
 
2 inch drop hitch works well. No need to buy an expensive anti away device. Works great on my 2008 pulling a 20ft Sea Ray.
 
mvalen said:
2 inch drop hitch works well. No need to buy an expensive anti away device. Works great on my 2008 pulling a 20ft Sea Ray.

(y)
 
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