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Author Topic:   Boat Weight; Using CAT Truck Scales
kjbuttleman posted 05-04-2004 03:04 PM ET (US)   Profile for kjbuttleman   Send Email to kjbuttleman  
I need to do some calculations for towing my recently purchased 1993 21-Walk Around. Does anyone know the gross weight, or know how to find out? It has a 225 Evinrude in case anyone just happens to know the weight of that motor too. Thanks in advance for the help.

I'm planning a trip from St. Paul, across Wisconsin to the Michigan UP and northwest part of the LP this summer -- several hundred miles of trailering overall. I want to make sure my tow vehicle doesn't find reason to object.

gimcrack225 posted 05-04-2004 06:27 PM ET (US)     Profile for gimcrack225    
Johnson 225 (1993) 25" shaft - 455 lbs
21 Walk Around 2600 lbs w/o fuel
92 gallon fuel tank (figure 6.25 lbs per gal)
plus the trailer and everything else
There are a lot of prior posts about Walkarounds and trailering them on the forum.
How do you like the boat?
Have fun
jimh posted 05-05-2004 09:21 AM ET (US)     Profile for jimh  Send Email to jimh     
To really find the boat weight, you have to weight the boat on a scale. Or you can try to deduce the boat weight from the published weights of the boat, the motor, all the equipment on-board, and the fuel in the boat.

When estimating towing load, also include yourself, any passengers, any gear, and the fuel in the towing vehicle. And don't forget the trailer itself, and any equipment related to it, like the hitch, spare tires, chains, etc. This is all part of the load that is rated in the vehicle's "maximum tow rating."

I find that although my hull only weighs 2200-lbs, I am probably close to the maximum 7,000 rating of my tow vehicle when we hit the road for a long vacation trip.

Moe posted 05-05-2004 10:12 AM ET (US)     Profile for Moe  Send Email to Moe     
Find your nearest CAT scale:

Fuel up and load up the tow vehicle and boat with all the people and cargo that will be in them on a trip.

Pull the rig up onto the scale pads. There are pads for the truck steer and drive axles and the trailer axle. Try not to get the tires near the edges of the pads.

Get back in the truck and call the operator. You'll probably need a broom pole to reach the call button from the truck seat.

When the scale operator asks for your ICC number, tell him, "private vehicle".

Once the operator tells you he has the weight, pull off the scale, and go park where you can drop the trailer off.

Take the tow vehicle across the front two scale pads. This time tell the operator, "private vehicle, reweigh" (cheaper)

Once the operator tells you he has the weight, pull off the scale and go inside to pay for your weight tickets.

Now you have the tow vehicle axle weights with and without the trailer. Don't be suprised if the truck's steer axle weight is lighter with the trailer than without.

Compare the individual truck axle weights when the trailer is connected with the truck's respective Gross Axle Weight Ratings (GAWR).

Compare the total truck weight when the the trailer is connected with the truck's Gross Vehicle Weight Rating (GVWR).

Compare the total rig weight with the truck's Gross Combined Weight Rating (GCWR).

The GAWR and GVWR should be on a sticker in the door jamb. The GCWR should be in the owners manual.

The trailer tongue weight is the sum of the steer and drive axle weights hitched up minus the sum of the steer and drive axle weights unhitched.

The trailer weight is the trailer axle weight plus the trailer tongue weight.

kjbuttleman posted 05-05-2004 01:32 PM ET (US)     Profile for kjbuttleman  Send Email to kjbuttleman     
Thanks for the numbers. In response to your quesstion, I really like this boat. I'm sure I'll like it even more once I get it in the water. I only got it last fall, and it's mostly sat in my driveway, looking sleek and shiny and reminding me of summer to come. It goes in next weekend.

Jim and Moe,
Thanks for the excellent advice. It turns out there is a CAT scale just down the road, so I'll verify the numbers there. I really appreciate the quick answers.

Your website is fantastic. I sold my old Montauk in a couple of days after placing a note in the "marketplace" part of this site. By the way, my new Walkaround used to live in your neighborhood. I bought it last September from Jeff and Rosie. Thanks again for the helpful information and the great website.

gimcrack225 posted 05-05-2004 04:02 PM ET (US)     Profile for gimcrack225    
That was an enlightening post. I'm going to do the same thing now that you've explained how to do it. I've always wondered how the vehicle weighing business operated. "Driven the back roads so I wouldn't get weighed"

Thats exactly where my '21WA is right now, in the driveway. I enjoy looking at it while I make breakfast. Don't they have a sharp looking hull. I think I notice a similarity to Moppie the first Ray Hunt Deep-Vee.
I also sold my Montauk last fall. Right now I'm doing some odds and ends on Gimcrack like GPS, washdown pump, kicker, new macerator, some new cushions, etc.

jimh posted 05-06-2004 07:32 AM ET (US)     Profile for jimh  Send Email to jimh     
You have a creampuff Boston Whaler--that was a very nice boat and Jeff had it in better-than-new condition. You should not have a problem hauling it on the highway if you have a half-ton truck or SUV rated for 6,000-7,000 pounds of towing capacity. Except for the western part of the Upper Peninsula, there probably won't be any elevation changes in your route greater than a hundred feet, so you towing will mainly be on level ground. That makes things much easier on the vehicle.
AQUANUT posted 05-06-2004 07:40 AM ET (US)     Profile for AQUANUT  Send Email to AQUANUT     
great post moe...again and again...great info..thanx
got two near me....I was using the states freebie near my house...udes to weigh log trucks..but it only weighs one axel at a time...certified weight ticket I think is better route..thanks again
jimh posted 05-06-2004 11:59 PM ET (US)     Profile for jimh  Send Email to jimh     
A random sample telephone call to a scale facility listed on the CAT Scale web site produced a quoted price of $8 for first weigh, $1 for a re-weigh. They seem to be distributed along interstate highways, particularly near state borders.
jimh posted 07-02-2004 08:33 AM ET (US)     Profile for jimh  Send Email to jimh     
Recently I found myself about to enter the New York State Turnpike with my new boat and trailer hitched to my vehicle. I had a full tank of gasoline in the truck, and I was at a service station that had a CAT SCALE. I could not resist the temptation to weight the rig.

The most important advice is to have a long pole to hit the button on the scale to notify the operator. It is positioned for the height of a semi-trailer tractor, not a pick-up truck or SUV.

This was the most interesting $9 I have ever spent. Here are the numbers:

My tow vehicle's
Specified limits:

GVWR = 6800
GAWR FRT = 3400
GAWR RR = 3968

Measured Weights:


Steer Axle = 2240
Drive Axle = 3880
Trailer Axle = 4860
TOTAL = 10980


Steer Axle = 2480
Drive Axle = 3120
TOTAL = 5600 (Total Vehicle Weight no driver or passenger)

Deduced Weights:

Trailer Weight = TOTAL(Hitched) - TOTAL(Unhitched)
= 10980 - 5380
= 5380
Tongue Weight = [STEER + DRIVE](Hitched) - [STEER + DRIVE](Unhitched)
= (2240 + 3880) - (2480 + 3120)
= 520
Tongue Weight = Trailer Weight - Trailer Axle
= 5380 - 4860
= 520

Comparison with Limits:
Front Axle Limit = 3400
Front Axle Meas. = 2480
Margin = 920

Rear Axle Limit = 3968
Rear Axle Meas. = 3880
Margin = 88 (Close!)

Front Axle
+ Rear Axle
(Hitched) = 2240 + 3880
= 6120
GVWR = 6800
Margin = 680 ( but no Driver or Passenger included!)

I should have had Chris and I stay in the truck during the weighing.
This would have added about 360 pounds to the totals.

I could tell from the springs that the tongue weight was considerable. I will be making some changes to reduce the tongue weight to a level closer to 5-percent of the trailer weight, which would be about 275-300 pounds. This will help reduce the rear axle loading, which is close to the limit.

Another thing to check is the tire ratings on each axle. I am using Michelin tires with a rating of 2183-pounds maximum load. This gives me a margin of 480 pounds. It is important to keep the tires inflated to the required pressure.

As a result of this analysis I have found that my current vehicle is being asked to operate at near maximum capacity when towing. This confirms the impression I got from the vehicle's response to driving, accelerating, braking, etc., with this load.

jimh posted 07-02-2004 08:44 AM ET (US)     Profile for jimh  Send Email to jimh     
I could not locate the vehicle's rated Gross Combined Weight Rating (GCWR). It is interesting to note that the combined weight of my rig will be in excess of 11,000 (when Chris and I get back into the truck). This is a rather significant amount of weight to be maneuvering on the highway, particularly when trying to stop.

The trailer has a surge braking system and has brakes on all axles. I find that this is giving good response to braking. I am particularly impressed with the DICO Model 6 brake coupler. This works very well, and this trailer actually seems to have better braking than my other trailer, which has brakes on only one axle.

Backlash posted 07-02-2004 08:49 PM ET (US)     Profile for Backlash  Send Email to Backlash     
That is a great 21 Walkaround in excellent shape. I know you'll enjoy it.

Fantastic information! I know where I'm heading tomorrow.

Very interesting...especially the 520# tongue weight! I'm afraid mine is probably similar. A weight distributing hitch would transfer weight from the rear axle to the front axle which would help in your situation.


Moe posted 07-02-2004 10:46 PM ET (US)     Profile for Moe  Send Email to Moe     
I'm glad this info helps. I personally would not tow a trailer with much less than 10% tongue weight, although I know boaters often go as low as 7%. If you've ever experienced severe sway, you'll not ever want to do that again. What tongue weight percentage is really telling you is where the center of mass is on the trailer, and the further back it is (the lighter the tongue weight), the more likely severe sway is to occur.

As Steve mentions, what weight distributing (WD) hitches do is put back on the front axle that weight that the tongue leveraged off it and put on the rear axle. In the process, they also put some of the tongue weight back on the trailer axles. Note that the weight distributed capacity of the hitch receiver on your vehicle is much higher than the weight carrying capacity.

WD hitches in themselves do not help fight sway, so the addition of friction sway controls, dual-cam sway devices, or the use of an Equal-I-Zer WD hitch, which combines friction sway control in the spring bars, can help. Two top of the line hitches, the Hensley Arrow and the Pullrite, completely eliminate the effect of sway on the tow vehicle, but are much more expensive.


jimh posted 07-03-2004 10:11 AM ET (US)     Profile for jimh  Send Email to jimh     
You will find that CAT Scales are often located near state borders. The one I found was near an entrance ramp to the Turnpike, which soon thereafter had a mandatory weight station for trucks to pass over.

Chris and I moved the boat about four inches farther back on the trailer last night. I am sure this reduced the tongue weight, but not precisely sure how much.

[Changed TOPIC: was "Finding Boat Weight."]

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