On Sun, 7 Dec 2003 02:57:24 -0500, "Gary Warner"
wrote:
Now, you make the tongue longer. That tongue has more leverage to
the piviting point (the axel). It would be easier to lift that tongue. It
would have *less* weight when put on the ball. To get back to
the 400# you would have to move the wheels *back* more.

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

Your analysis is correct. You could either move the axles back a
little more, or bring the boat forward. I have a similar setup to
yours: 24 ft boat, approx 5,000 lbs, tandem axle trailer about 28 ft
long. Moving the boat forward 1 foot increases tongue weight by about
300 lbs. Once you get the axles about right, it's easier to adjust
the boat position.

"Wayne.B" wrote:

Your analysis is correct. You could either move the axles back a
little more, or bring the boat forward. I have a similar setup to
yours: 24 ft boat, approx 5,000 lbs, tandem axle trailer about 28 ft
long. Moving the boat forward 1 foot increases tongue weight by about
300 lbs. Once you get the axles about right, it's easier to adjust
the boat position.

Thanks.

Note: In our case we don't want to move the boat
forward. Reason is that it's a wood boat and there is
a 50 gallon gas tank right at the back going
across the boat. We want support right under the transom.
So we want the transom directly over the end of the trailer
where the risers will be.

"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.

Get the boat where you want it. Then make the tongue the length you want
it. Finally move the axle to get 10% of the weight on the tongue.

"Gary Warner" wrote in message
...


"Wayne.B" wrote:

Your analysis is correct. You could either move the axles back a
little more, or bring the boat forward. I have a similar setup to
yours: 24 ft boat, approx 5,000 lbs, tandem axle trailer about 28 ft
long. Moving the boat forward 1 foot increases tongue weight by about
300 lbs. Once you get the axles about right, it's easier to adjust
the boat position.

Thanks.

Note: In our case we don't want to move the boat
forward. Reason is that it's a wood boat and there is
a 50 gallon gas tank right at the back going
across the boat. We want support right under the transom.
So we want the transom directly over the end of the trailer
where the risers will be.

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:
Snafu wrote:

Gary, I'm not understanding the part about "the longer the tongue, the
furthur back we can put the wheels." To maintain the ~10% of the weight

on

the hitch rule, increasing the tongue length works the opposite way.

Absolutely the longer the tongue (drawbar?) the further "forward" the
wheels will by to keep the balance right.



Say you have a rig, single axel, 24' long from back to tip of tongue. The
center of gravity of boat + trailer is @ 8' from the back. So if the axel
was
at 8' the thing would essentially be balanced over the axel, no weight on
the tongue.

Then you move the wheels back until you get the desired 10% / 400#
on the tongue. Say you have to move it 1' to do that. So now the
axel is at 7' from the back.

Now, you make the tongue longer. That tongue has more leverage to
the piviting point (the axel). It would be easier to lift that tongue. It
would have *less* weight when put on the ball. To get back to
the 400# you would have to move the wheels *back* more.

By tongue I do NOT mean the draw bar on the truck. I mean
that the length of the "pole" hanging out the front of the trailer
is extended and made longer.


If I'm thinking of this wrong I'd love to hear it...but I think I'm right
and more likely we just aren't picturing the same thing / using the
same language.


Thanks,
Gary


PS: Ours will actually be dual-axel and these numbers are just a guess
at what our situation will be...I don't know the actual weights or
centers-of-gravity yet. Our boat is 3800 to 4000 lbs and I think
the trailer will be 1200 or so.



Now you say it that way yes I now totally accept you're correct all
along & my apologies. I screwed up.

K

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

"K Smith" wrote:

Now you say it that way yes I now totally accept you're correct all
along & my apologies. I screwed up.

K


Thanks for the input, no appologies ever necessary if the intent is all
good.