Here's a little more on trailer weight adjustments, for anyone who may need
further information. What follows is drawn from the extensive efforts I've
made to get boat/trailer combinations up to 4,000 pounds to trailer

Proper tongue weight is essential to comfort, the ability to trailer the
boat at high speeds, and safety. The effect of too much tongue weight is a
sort of lurching or bucking motion (up and down, fore and aft) felt in the
tow vehicle. The effect of too little is fishtailing by the trailer, which
will be felt in the tow vehicle as a side-to-side tugging and, in any case,
can be seen in the rear-view mirror, especially coming out of a curve. 

The heavier the boat in relation to the tow vehicle, the greater the issue,
so getting the tongue weight into the optimum range will be more critical
for an M-17 towed behind a small car than for an M-15 towed behind a large

If your combined trailering weight is high enough that 10% will not register
on a bathroom scale (or if your scale is simply not accurate in the higher
ranges), you can go to a weigh station and first weigh your car without the
trailer attached and then weigh the car (just the car) with the trailer
attached. The difference between the two weights is the tongue weight.

Alternatively, you can construct two piles of bricks (or books or whatever)
equidistant from both sides of your trailer tongue, such that they are the
same height when the bathroom scale is set on top of one of the piles. Then
put a piece of wood across the top of the two piles and lower the trailer
receiver down onto the wood exactly in the center between the two piles.

Using this system, the scale will register one-half of the tongue weight,
and you can double it to get the figure to evaluate against the 10% rule.

Note that different trailer/vehicle combinations may perform better with
slightly differing percentages. Once you settle on the desired weight, go
out driving under fairly extreme conditions (high speeds with hills and
curves). If the boat bucks, reduce the tongue weight. If it fishtails,
increase it. Otherwise, as long as the tongue weight is within the range
specified for your vehicle and hitch, you are fine.

Using these methods, you should be able to trailer comfortably at speeds up
to 70 mph or a little more on super highways, even with a heavy boat
(assuming a well-matched tow vehicle). You may not be able to control
fishtailing no matter how you adjust things much beyond 70. At high speed,
coming over a hill and starting down while going into a curve at the same
time will give you the acid test. 

The majority of drivers, I think, will be content with being able to trailer
comfortably at speeds up to 70 mph on super highways. You could probably go
faster with an M-15 behind a vehicle which weighs significantly more than
the boat and trailer, but that will depend, among other things, on your
tolerance for risk.

-- Jeff Mirus
   Precision 23 Owner
   Montgomery Fan


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