"Steven Shelikoff" wrote

That's assuming it's a perfect theoretical lever where the weight of the
lever itself is 0, which it's not. The actual answer is "it depends".
For example, if the tongue weight is currently 10lbs and you double the
length of the tongue but the extra length weighs 20lbs, you'll be
increasing the tongue weight. But if the current tongue weight is
1000lbs and you double the length same as above, you'll be decreasing
the tongue weight.

With a real world trailer, doubling the tongue length would cause the
new tongue weight to be somewhere between (old weight+weight of new
tongue length) and (old weight/2) but never actually being equal to
either of those unless you use some sort of extra load leveling device.

Steve

Right. And in most cases the added tongue material (in our case about
7 lbs/foot) is minimal compared to the tongue weight 400#.

"Wwj2110" wrote in message
...
If you increase the tongue length, you will increase the tongue weight
by exactly the amount of weight of the added tongue material. Leverage
has nothing to do with the tongue weight. If you move the axles
backward you will increase the tongue weight, forward will decrease the
tongue weight. Tom.

I disagree. A trailer is just a class 2 lever. If the distance
between
the wheels & the ball were doubled, the tongue weight would be cut in
half.

I'm sorry, I'm just not following this train of thought. Let's forget a
trailer for a moment. Take an object that is long, like a 10' piece of pipe
for instance, and lay it on the ground to simulate the trailer. Support the
pipe at say 60% of its length with another object, say like a 2x2, to
simulate the axle. The longer end of the pipe is the tongue end; weigh the
very end of the long end. Now move your 2x2 so that the tongue end is 90%
of the pipe's length. Now weigh the long end. Won't the weight at the end
of the long end be greater that it was when the 2x2 was at only 60% of the
length?

It really depends upon the center of mass of the boat in relation to the
axle position. If the center of mass is directly above or behind the
axles you will end up with neutral or negative tongue weight(dangerous
situation). Ideally, the center of mass of the boat should be just ahead
of the axles, just enough to give you the tongue weight you're shooting
for. All else being equal/unchanged increasing the tongue length will
increase tongue weight by the amount of extra material in the tongue.
However the longer tongue does have advantages in more predictable
maneuvering/backing, and in longer reach at a shallow angle launch ramp.
Tom.

On Sun, 7 Dec 2003 16:31:25 -0500 (EST), wrote:

It really depends upon the center of mass of the boat in relation to the
axle position. If the center of mass is directly above or behind the
axles you will end up with neutral or negative tongue weight(dangerous
situation). Ideally, the center of mass of the boat should be just ahead
of the axles, just enough to give you the tongue weight you're shooting
for. All else being equal/unchanged increasing the tongue length will
increase tongue weight by the amount of extra material in the tongue.

Sorry, but that's just not true. Even if you discount the fact that the
tongue is acting like a lever, not *all* of the extra weight of
lenghtening the tongue is supported by the hitch. Some of it is also
supported by the trailer wheels. The only way this would not be true is
if all of the added weight of the new length of tongue was centered
right over the hitch, which isn't likely. Now, if you take into account
the fact that the extra tongue is lengthening the lever, the only way
the tongue weight will be greater by doubling the tongue length is if
the extra material in the tongue weighs more than over half the original
tongue weight.

Steve

wrote in message
...

Ideally, the center of mass of the boat should be just ahead
of the axles, just enough to give you the tongue weight you're shooting
for. All else being equal/unchanged increasing the tongue length will
increase tongue weight by the amount of extra material in the tongue.

That's true, the tongue weight will increase by the weight of the
added material. (Actually, as Steven pointed out, some of that
added weight will also be supported by the whels.) But most
of it is nearer to the ball, and most will be supported there.

BUT, the weight of the added material is very small
and I believe can essentially be forgotten about. In our
example, an extra 3 feet of tonge would be maybe 20 lbs
of material. When we're looking for a tongue weight of
400#s, thats nominal.

What is ALSO true is that that longer tongue (all else
staying the same) moves the end of the tongue farther
away from the pivot point (axel). A longer arm (tongue)
gives more leverage. It would be easier to lift that
tongue off the ground or up off the ball. There would
be "less tonge weight".

On Sun, 07 Dec 2003 19:43:58 GMT, "Snafu"
wrote:
Now move your 2x2 so that the tongue end is 90%
of the pipe's length. Now weigh the long end. Won't the weight at the end
of the long end be greater that it was when the 2x2 was at only 60% of the
length?

======================================

When you move the 2x2 in your example, that is comparable to moving
the axles towards the back of the trailer. Thats not the same thing
as increasing your tongue length and leaving everything else the same.

"Gary Warner" wrote in message
...

So, any other problems with having a longer trailer tongue?

I have had this argument before, and don't wish to get back into the
mechanics of stability arguments again. BUT......


First word of caution: The 10% tongue weight is a "rule of thumb". Having
10% tongue weight won't necessarialy result in stable rig. Not having 10%
won't necessarialy make it unstable. Having too much will certainly load
down the tow vehicle, which could create problems. Not having enough will
certainly make a receiver type hitch rattle a lot more, and could make the
tongue pop off the ball when you hit bumps in the road.

What makes a trailer stable is the stiffness of the connection between the
axels and the load (springs, center of mass, trailer rigidity, etc.) and the
stiffness of the trailer with load to the tow vehicle (trailer rigidity,
distribution of mass).

For the purpose of discussion, take two trailers, each 20 feet long, axels
in the middle:

Trailer A has all its load located essentially over the axel Tongue weight
could be neutral. Other than the risk of the hitch popping off the ball,
this trailer could tow very nicely.

For trailer B the load is separated into two sections. A little more than
half of the load is centered 5 feet forward of the axels, the remainder of
the load is 5 feet back of the axels. This trailer has the "desired" 10%
tongue weight. Unfortunately, it is likely to sway terribly as you go down
the road.

The difference between these two trailers is the moment arm of the mass. It
isn't a "statics" problem, it is a "dynamics" problem.

To address your exact question: you could have possible problem with a
longer tongue if you don't compensate for the extra "spring". A short
trailer would be "stiff". If you use the same construction and stretch it,
the trailer will become more flexible. This can be very bad. You can avoid
this by making the tongue section more robust. When you figure the load on
the trailer you should consider more than just how gravity effects it. You
need to also consider the side loads during cornering, or when hit by the
wind blast of a passing truck.

You can have a long tongue, there is nothing wrong with that. But it is a
different trailer design than just taking a short trailer and extending it.

Rod McInnis

Everybody else seems to have gone off on the relative tongue weight.

Other factors:

A longer tongue will back up more stable, but be less maneuverable when backing.

A longer tongue will help keep your truck out of the salt water.

With a long tongue, I'd consider adding trailer running lights under the bow
somewhere. It can be a long way between the back of your truck and
the first running lights on the trailer. Several years ago, I damn near
center-punched a Corvette on a trailer with no lights between the back
of the truck and the back of the trailer. He came out of a blind side street
on a rainy night, and it sure looked like just the tow vehicle. I got all kinds
of sideways avoiding the trailer, no harm, no foul, but some running lights
on the trailer would have kept my adrenaline level down. My Shorland'r
trailer has a long tongue from the factory, and I added running lights under
the bow (there was already a set at the front of the trailer fenders).

Finally, several folks have said 10% on the tongue. I've seen lots of recommendations
of 5-10%, mine is 5% and OK.


--
Chuck Tribolet

http://www.almaden.ibm.com/cs/people/triblet

Silicon Valley: STILL the best day job in the world.


"Gary Warner" wrote in message ...

Designing our trailer it looks like for our 22' boat we could have the
tongue as litle as 2' from the bow -- or 24' total rig. But we'ld like to
put the wheels (tandem) as far back as possible so less boat and
less weight is hanging out past the wheels. This should help
stability. SO, the longer the tongue, the furthur back we can
put the wheels. ~ Storage of the trailer is no problem and though
a longer rig makes tight manuvering harder I don't think we'll
have any major prolems with that.

So, any other problems with having a longer trailer tongue?

It is a great suggestion regarding adding lights to the extended tongue. I
never thought of the sideways "blind spot" due to an extended trailer
tongue. I added 3 feet onto my little trailer and do NOT have any lights
forward of the aft end of the boat. You've given me a project for the
weekend. .......thanks....

p.s. regarding an extended tongue making backing up "less
maneuverable"...yes, but, the longer the trailer/tongue, the BETTER the
trailer backs up. Think of an 18 wheeler backing up in Wal-Mart's parking
lot and think of you backing a short boat on a short trailer down a ramp. It
is true that the 18 wheeler needs MORE ROOM to maneuver ( and that is
probably exactly what you said) but I'll back down an 18 wheeler anytime
versus a 14 foot boat trailer. regards. RichG


"Chuck Tribolet" wrote in message
...
Everybody else seems to have gone off on the relative tongue weight.

Other factors:

A longer tongue will back up more stable, but be less maneuverable when
backing.

A longer tongue will help keep your truck out of the salt water.

With a long tongue, I'd consider adding trailer running lights under the
bow
somewhere. It can be a long way between the back of your truck and
the first running lights on the trailer. Several years ago, I damn near
center-punched a Corvette on a trailer with no lights between the back
of the truck and the back of the trailer. He came out of a blind side
street
on a rainy night, and it sure looked like just the tow vehicle. I got
all kinds
of sideways avoiding the trailer, no harm, no foul, but some running
lights
on the trailer would have kept my adrenaline level down. My Shorland'r
trailer has a long tongue from the factory, and I added running lights
under
the bow (there was already a set at the front of the trailer fenders).

Finally, several folks have said 10% on the tongue. I've seen lots of
recommendations
of 5-10%, mine is 5% and OK.


--
Chuck Tribolet

http://www.almaden.ibm.com/cs/people/triblet

Silicon Valley: STILL the best day job in the world.


"Gary Warner" wrote in message
...

Designing our trailer it looks like for our 22' boat we could have the
tongue as litle as 2' from the bow -- or 24' total rig. But we'ld like
to
put the wheels (tandem) as far back as possible so less boat and
less weight is hanging out past the wheels. This should help
stability. SO, the longer the tongue, the furthur back we can
put the wheels. ~ Storage of the trailer is no problem and though
a longer rig makes tight manuvering harder I don't think we'll
have any major prolems with that.

So, any other problems with having a longer trailer tongue?

"RG" wrote in message
...

p.s. regarding an extended tongue making backing up "less
maneuverable"...yes, but, the longer the trailer/tongue, the BETTER the
trailer backs up.

That depends on your tow vehicle and what you consider to be "better".


The shorter the distance between the hitch and the trailer wheels, the
faster the trailer turns. This can be GREAT for maneuvering in tight
quarters, IF your tow vehicle can turn to match it. If you have a long
wheel base tow vehicle (slow turning) and a short wheel base trailer you can
end up having something that is a bitch to back up. If you are really good
at handling it you can prevent the trailer from getting into a turn that you
can't recover from (without pulling forward). Such a driver might not mind
this trailer characteristics.

A fair percentage of the people I see at the boat ramps would be much better
off with a much longer wheel base trailer!

Rod McInnis