Towing Issue - Porpoising

[YeahBuoy]

This maybe a stupid question but I am going to ask anyway. I picked up my new Pontoon boat this weekend, my issue is the trailer is porpoising when I am driving down the road. I am towing with my RAM 2500 with 35" KO2's, so its not a suspension issue because the boat & trailer only weigh about 3200 Lbs. I have a 5" drop hitch.

Here is where I get conflicting info. The dealer said the boat should sit level and it does, the net says 10%-13% tongue weight and other say 15% tongue weight.

I always thought the trailer should be pointing down slightly to keep the weight in the tongue. The trailer feels like its lifting and pushing as I go down the road. Besides being annoying I would think it cant be good for the drive train.

Any suggestions on what to try next?

Here is my set-up.

[ishoot]

Sounds like you need more tongue weight. Can you weigh the tongue of your trailer to confirm? If not, you can get a rough idea simply on how hard it is to jack up. If it jacks up real easy you probably don't have enough tongue weight. Can you pickup the tongue when boat is loaded?...not enough tongue weight if you can.

Trailer should be level not pointing down.

Proper tongue weight is between 10%-15%. Somewhere around 400 lbs should be good in your situation.

There's a couple ways to increase tongue weight. One way is to move the axles back till the desired weight is attained on the tongue. Many trailers offer adjustable axles. The other way is to move the front vertical boat stop forward if you have room to do so. Just a little bit makes a big difference! Be careful however when moving forward that your turn radius is not hindered by jack-knifing.

Good Luck!

Dan

[BobG]

I agree with the "not enough tongue weight".

And why would your dealer not want to deal with that?
Because in order to increase your tongue weight, one of two things has to happen:

1. Move the bow stop (and therefore the entire boat) farther forward on the trailer. Not a huge deal, but it takes time. Or, if the bow stop is all the way forward,
2. Move the axle(s) BACK. This is a real PITA, and easy to get wrong.

[STEVEBRENDA]

Easiest way to test it is to fill a couple of big coolers full of water or something similar. Test drive it to see if taht helps - if so, move th boat forward,.

[RcgTexas]

Tongue weight is too light, and yes why isn't the dealer fixing this??

The porpoising thing threw me for a second there.

[COTTS4x4]

It looks like you have enough bunk sticking out in front of the boat, that will let you move the boat forward on the trailer without having an issue there. I had to move my boat forward to get the tongue weight right. On a single axle trailer like yours and towing with a 3/4 ton I prefer to have a little too much tongue weight. Just loosen the u-bolts on the bow post and move it toward the truck 6", check to be sure the boat is still on the bunks fine and I think you'll find that will do the trick.

I looked at a boat through Astor marine before I bought my boat too.

[zoom650]

I used a ratcheting strap from the bow eye down to the trailer frame to keep my bow from moving up and down. It helped when towing.

[grouser]

I agree with checking your tongue weight and keeping the boat level. I will share this with you. My 30' Party Hut will act like what your saying if I don't re-tighten the winch strap after pulling her out of the water. There is a bit of flex in the trailer and if I don't cinch her down she bounces down the road. The strap should have a fair amount of load on it to hold her tight to the trailer. Let us know what you find works.

[pond tuuunes]

Atleast 10 % tounge weight, that 2500 should have no problem with 15%. Thats a single axle trailer? (Sorry looking from cell phone) i would say move the toon as far forward as possible. jt

[ishoot]

zoom650 makes a good point...I too strap down the two outer toons at their eyes both front and rear with ratchet straps. This helps make the boat and trailer ride as one load and really helps with towing and any bouncing.

[Seon]

Here's a link on how to weigh your trailer tongue.

http://hildstrom.com/projects/tonguescale/index.html

[YeahBuoy]

Here's a link on how to weigh your trailer tongue.

http://hildstrom.com/projects/tonguescale/index.html

Thank you Sir

[Bryden24shp]

Agreed, tongue weight is important, but strapping the bow down to the trailer on highway runs does eliminate a lot of the dipping too. I ratchet strap the bow down and use 2 more from the bow eyes on the nosecones to the bunk supports and take the weight off the winch strap. I've had the winch strap break while highway towing the Baja, It was a ride from hell until I could stop and fix it. Thank god for the safey chain! I eventually made a steel clip from 2 bolts with U's on the ends and a turnbuckle in the middle. Like a clothes line tightener... Worked fantastic on the Baja.

[Seon]

Speaking of front straps, who uses hold down straps at the back end?

Reason I ask is because the previous and current Toons I've owned didn't have hold down straps but I put "Eye" bolts to the cross member and trailer frame then attach the straps.

Some say they're not needed because of their weight and aren't going anywhere.

I say, they are needed in case of an accident; I don’t want a "sling shot" effect, either forward or reverse.

[BobG]

In addition to ratchet straps front and rear, I have a 2" ratchet strap that goes from the bottom of the middle tube, around the frame, and back to the bottom of the middle tube, pulling the boat forward on the trailer. That bow stop is pretty flexy!