Tongue Weight Adjustment

Just a thought: to increase the weight on the tow hook it might be easier to move the boat forward on the trailer, or failing that take off the outboard and place it in the bows during the road journey. Or failing that fill the bows up with supplies.

"A statistician uses mathematics in the same way as a drunk uses a lamp-post - for support rather than illumination."

It might be worth checking with the original equipment manufacturer that the rear suspension of the towing vehicle is stiff enough for the application and whether the correct grade tyres are in use, at the correct pressures.

If buying a four wheel trailer is out of the question then try a tow-hitch damper. We found that to be effective with a two-wheel car trailer. I've towed all sorts of things with all sorts of weight distribution and conclude that loading the tow hitch isn't very effective in stoppong the tail wagging the dog.

What are you towing with? The inertias of the vehicle and trailer must be the main factors. I like the suggestion of moving the motor and the stowed equipment around, it'll affect the inertia, never mind the weight on the hitch.

Neglecting wind resistance for the moment, if the trailer were to be perfectly balanced, then only a minor disturbance to the alignment of the trailer by some pot-hole or roadkill for example would cause its direction to change. This would carry on until all the slack in the mechanical doobries have been used up. The towing vehicle then tries to correct the alignment by applying a restoring force, changing the alignment again, and again, and again, and again (the tail wagging the dog). and if the tail is heavier than the dog, then the tail will win........

The problem is that the trailer cannot align itself along the same axis as the towing vehicle unless the centre of gravity is well forward of the axle, in which case the 'system' can be said to be 'damped', by observation. Such an arrangement places a significant part of the trailer's weight upon the tow hook of the towing vehicle. 10/3550ths is way too small! However, too much weight can cause the nose of the towing vehicle to lift, adversely affecting steering and stability.

There is some mathematics one can use to sort it out from a theoretical standpoint. Its called S-plane algebra. Good luck with it!

On a more practical basis there's a load of stuff on the 'net about towing, vehicle weights, tongue weights, etc., which is well worth reading.

[Background info: there are 'grandparent rights' on some driving licences in the UK that permit the longer-licensed driver to tow a trailer legally without taking an additional test and upon the basis of driving experience; someone who passed a car driving test after 1st January 1997 needs a separate practical assessment and licensing for some trailer towing as the regulations have been tightened since then with a view to reducing road accidents. The weight of the trailer and load stated above is way over the non-assessment criteria for UK roads and, were such a combination to be considered here, training and practical assessment would be the only legal route available.]

Tail wagging the dog is often caused by misalignment of trailer wheels. Have you checked that?

I have the solution.

I had the same problem for years on a piece of equipment and tried all the above mentioned ideas.

The way to fix it is very simple drop the height of the hitch,trust me it will work.

If you have a receiver it is easy to get different drops or get an adjustable type.

Or simply try a different vehicle with a lower hitch to prove the theory.

There are many benefits to propber hitch height. For farm vehicles, the advice was to never have a hitch higher than 13", due to stability and potential rollover issues. A lower hitch point lowers the force lines closer to the ground to promote stability.

I'm wondering if your tires are radial type? I've had problems with those type tires with a heavy weight like your pulling. They can start the fish-tailing and wind up getting worst as the tires flex back and forth. Something with a 4 ply sidewall won't do this as bad. Also 10 lbs. is not enough on the hitch. I would go to at least 50-75 lbs. and like another fellow mentioned keep the front down a little if possible. I built my own trailer for a steamboat that is over 2000lbs. and it trailers just fine. I have a construction article on my website as to how I built the trailer and also how I placed the single axle under it for the correct balance. Just hit trailer in the sidebar and it will bring you there.

http://www.mysidewheeler.com

Ken Brockway

I forgot to mention that the normal tongue weight should be between 10-15 percent of the gross weight making yours well over 300 lbs. I found mine was fine at about 60lbs according to a scale used to measure it. I also make sure I load everything forward of the axle.

Ken Brockway

300 lbs tongue weight would be highly illegal in Europe.....50-75 Kgs or between 100 and 150Lbs is normal.....

Thats interesting because 300lbs on a 3000lb trailer is safe assuming the hitch and vehicle are rated for such. Low tongue weight or overloading vehicles can create unsafe situations. Check this out for a laugh.

http://www.youtube.com/watch?v=Tx0xzqQyMUY

A ball hitch in Europe is seldom allowed to have more than 100 KG or 200 lbs on it....no matter how beefy the tow car is......

Generally 75 kg is max.....

But Europe is not America......so I am not certain that 300 lbs is necessarily wrong in the USA as I don't know that....

Also, most of the cars in Europe probably aren't rated to tow more than 2000lbs (I'd imagine) so those tongue weights make sense.

I'm from Boston, however today I'm in Rome getting reminded of how small the cars people drive are. No F350 Superdutys here! When's the USA going to wake up and realize that small can be practical! Small cars such as the "Smart" would be perfect for major cities. They can park perpendicular to streets the same way cycles do!

A UK motoring organization recommends 4% or 25 kg, whichever is the greater as a possible starting point for nose weight.

I tend to agree using my own experiences over many years...

I would think bolting extra weight to the tongue would be easier than moving the axle, springs, mounts etc. Spare tire holder, water can, anvil, rebars, 1ft square by 2"-4" thick steel step would also keep your feet dry when hooking the tow cable. The math is alot easier, 1 water can + 1 gal H2o + 1gal H2o + ...

Ditto on lowering the hitch, worked for my skidsteer.

Assuming you are towing the trailer level. You mentioned, "highway speed," and that is most likely the answer to your problem. Far to many folks these days are no longer aware that non-commercial combinations should never be driven more than 45 mph, 55 max.--as the thousand of accidents will attest to. When a trailer starts to fish tail simply ease of the gas (never brake) until the trailer gets in line and maintain that speed or lower and your problem should go away. It is doubtful that you would be able to gain any significant difference (assuming the load in the boat is trimmed) moving the trailer axle...and you could impair steering of the tow vehicle. Safest to assume that the trailer is balanced correctly if it's not home made. Further word: if you are towing in California, better be on guard for Highway Patrol to pull you over. Seems that just a few days ago an entire family was wiped out trying another common trailer pulling stunt: trying to tow a loaded car tailer with a car...always a no-no. So now the highway patrol is really cracking down.

I'm aways amazed at what i see people towing with their cars.

I have a 3/4 ton truck and would tow some of the stuff I see being towed with the small trucks they sell these days.

Aways check your allowed weights before hauling anything. Cars & truck are only deigned to carry so much weight. And secure the loads properly. I've seen boats come off trailers because the idiot towing it did not bother to tie it down to the trailer.

I'm not saying this is your problem with the boat. Just that this thought popped into my head when I read this post.

Dear Guest, if you look at the recommendations from such services as the British AA or the German ADAC (if you can read German) plus many magazines who cater for people who tow, you will find that what you said was and is completely wrong:-

When a trailer starts to fish tail simply ease of the gas (never brake) until the trailer gets in line and maintain that speed or lower and your problem should go away.

You should brake firmly. I know it takes guts the first time, but it works INSTANTLY!!! I know I have been there several times and it just works. Tow cars with ABS and ESP work even better....

No matter how well setup your rig is and no matter how well you drive, this will happen to you occasionally, so be prepared to brake firmly.....not violently. Hard, but not hard enough to cause any squealing (except maybe from your passenger(s)!!! from tires or brakes....

Thanks Andy. British AA???

I would certainly hope to see the guidelines you recommend. But, let us assume...that the brake firm advise is the way to go. Better still...that it is preferable but that either way done competently will result in curtailing of a "wild trailer" hazard. That being the case, I would be very hesitant to advise anyone to brake firmly in such a situation...for fear that they might apply the advise when, say, towing down a steep mountain road, and/or in icy or wet conditions...where the trailer could lose traction and pass the tow vehicle in a jack knife maneuver. But again, as I said, I would hope to see the guidelines you mention in order to get the entire story about how the braking maneuver accomplishes the result you speak of with no chance of unexpected loss of control.

If you are ever in the situation, do not forget my advice.....as you really do not have much time to play about testing what will work and what does not.

The general advice of just taking your foot off the gas and steer a straight line (impossible to do!) will only work if :-

a) you are not on a downhill stretch of any sort (in fact you need to be going uphill with the wind in your face!)

b) You do not have a strong following wind

c) you are not say clocking 20mph or more, MORE than your trailer should be doing, as just taking your foot off will not bring a good result before you and the trailer are upside down in the ditch!

I was in a a) + c) situation with a strong side wind.......!!!!

I hope none of you ever get in the situation, but if you do, you MUST stop the oscillation within probably 4 - 8 seconds max......or you are Toast!!

Tail wagging the dog is not enough tongue weight or hitch too high.

*** Rule of Thumb is 10% of trailer weight on the hitch.

*** The trailer should also be level when towing.

Adjust the ball height, use a bathroom scale under the trailer jack.

I have been towing trailers for over 40 years with everything from a motorcycle to a tractor-trailer rig rated for 500,000#

I have a couple of a adjustable ball mounts so I can tow a motorcycle trailer, a log splitter, a small boat trailer, a dump trailer or any one's trailer that needs to be moved.

Most of the time I see guys with "High Rise" trucks trying to haul a small trailer at about a 15-20 degree angle and they are all over the road.

Or the trailer is so heavy that their rear bumper is almost dragging on the ground and they are all over the road.

Get your hitch weight right, make it level and maybe you can top the ticket I got in Texas once while towing a 32' camp trailer. 115mph! No wagging though.

10lbs of tongue weight! HOLY COW MAN! That is your problem. When accelerating or going up hills you will have negative tongue weight when your CG shifts back.

You probably want 5-15% depending on your trailer and hitch rating. You only have 0.3%!!! Yes, move the boat forward or the axle back. Your problem will stop.

Thanks everyone for your responses. They are much appreciated and I will move ahead and tackle the problem.

Since I do have room to move the axle aft that will be the first modification. In order to move the boat forward it would mean some changes to the roller setup at the bow due to the Load Rite trailer having a centre tongue that would hit the bottom of the bow of the boat if the boat were simply moved ahead. Guess I'll jack the trailer and loosen the axle clamps then use the 5 lb persuader to inch back the wheels about 6 inches.

In answer to some of your questions:

The tow vehicle is a Chevy Tahoe 4x4.

Boat is an 18ft Boston Whaler Outrage with a 135 HP Merc (450 lbs on the stern)

No gear stowed in the boat to offset the balance.

I'll report back on the new tongue weight and the 'success.'

Thanks

Brian

Those are awesome boats. I had a 17 Montauk. I felt safer in rough seas in that then I do in my 26ft runabout. Just be gentle as a good whack can damage the hull quite easily. Those boats are like hard boiled eggs. Foam wrapped in fiberglass so a good tap from a rock can cause a soft spot.

Feel free to play around with the trailer, they are very adjustable. Your Tahoe can tow way more boat than that and probably has a class 3 or 4 hitch that can carry a 500lb TW. Never use an OEM bumper hitch.