Link to Grumman Canoe Info via serial number?

Advice
#1

Hello All,

Just joined the community and regret having to start by asking for information regarding an older Grumman that was purchased used several years ago and will soon be gifted to my son. Also being new here I imagine this has been asked numerous times before, but have yet to find a topic search button and do see a “Similar Topic” pop up which I can’t seem to open to review responses.

Regarding mine, it’s a model G1540C and remember being told it is the rarer “lightweight” model which supposedly may be the 0.040" hull thickness weighing either 49 or 60 pounds. Can’t seem to find the information anywhere on the canoe and would like to pass on with information as to actual weight and manufacture date. With the decades long popularity and countless sales of Grumman one would think information easy to find, however from other posts here it seems impossible, or at least difficult, to access information on them. Have called Marathon Boat with no answer (or prompt return) of voice and email. Did find dealer information from an attached sticker, but they no longer sell them and have incomplete records.

Just wonder if I’ve missed something or a listing of serial numbers and information is available online somewhere.

Would appreciate any further info.

Thanks

#2

Just put a micrometer on the hull below the gunwale and measure the thickness of the skin, ie. .040".

Hang the canoe from a “fish scale” and weigh it.

#3

I just looked at the Marathon Boat website to see what info is provided about Grumman canoes, and since the last time I looked there, they have greatly reduced the number of options in terms of variations in how the different boats are constructed, and they have greatly reduced the amount of info regarding hull materials, so the current website is of no help.

Is this a 15-foot canoe (or very close to that length)? I sort of guess it might be, based on the model number. In any case, the difference between 49 and 60 pounds is a lot, and I wonder if you are providing the weight figures for lightweight and standard versions of the same boat, rather than two possible options for the lightweight version. The listed weight for what is likely the former “standard” version of their 15-foot canoe is 69 pounds, not 60, but 49 pounds sounds to me like a plausible weight for a thin-skinned aluminum canoe of that length.

Anyway, most people don’t have a micrometer to measure hull thickness and not many have a hanging-style scale with a capacity approaching 70 pounds, but everyone has a bathroom scale, and that will do the trick. Here’s how.

Set the boat on level ground, preferably concrete or asphalt, with each end sitting on two STACKED sections of 2x4 lumber (to describe this more precisely, the 2x4’s are positioned “flat” on the ground, but stacked one on top of the other to double the overall thickness). You’ll need to put the lumber for each support point a few feet toward center from the ends so that there’s enough hull width for the boat to not tip over and touch the ground at some other location. Each point of support needs to be the same distance from its end of the canoe, so that each support point is carrying the same share of the weight as the other. Now, for one of those support points, replace the lower piece of lumber with your bathroom scale (the remaining upper piece of 2x4 transfers the supported weight to a small enough area of the scale for the scale to function). Bingo! That scale is now reading one-half of the boat’s weight.

If anyone needs an explanation on why the support points should be constructed and positioned in this way, I’ll be happy to provide it. Suffice it to say, your weight reading will be wrong if one end of the canoe is sitting on the ground instead of being supported at a particular spot - a spot which does not “wander” as a result of slight changes in “levelness” of the boat.

Yeah, if you really want to be accurate you must place the scale first at one end and then the other, and then add the two weights, but the single reading taken at one point of support as described above will be really close to half the total weight. Oh, and use the shortest sections of 2x4 that you you can, so you can just ignore the weight of the lumber. If you use long pieces of 2x4 you’ll have to determine the weight of the one that is sitting on the scale and subtract that from your scale reading.

#4

What I do to weigh a boat is pick it up, get on the scale, note the weight. Then weigh myself without the boat and subtract.

1 Like
#5

The G1540C model number does refer to the lighter gauge 40 mil 15’ double-ender. The weight is 59 lbs. The standard model is 50 mil and 69 lbs. I found this information by Googling for Grumman catalogs/brochures.

Now on to the age. I think it’s 1984 or later, but you’ll have to check the hull identification number (HIN) to find out the year & month.

Pre-1972 boats don’t have a hull identification number (HIN) and were marked like this: 12345-G-5-15, where the 12345 is the serial number, G is the batch, 5 indicates 50 mil, and 15 is the length. From 1972 on, there should be a 12-digit HIN near the stern of the canoe. On ours, it was stamped into a little plate that was riveted to the side of the canoe. HIN requirements changed again in 1984, and I think this was the year that Grumman stopped using the old marking format. Since the serial number is part of the HIN, they stopped stamping it on the nameplate. I believe that’s when they started using the model designation you have.

Another clue to the age is the gauge. The original Grumman lightweight models were 32 mil (0.032"). The 15 footer was 55 lbs. The newer models are 40 mil. I recall the change happened in the 1980s, but I can’t remember what year.

Since I’m pretty sure you have a 1984 or later model, the HIN will be in the following format:
GBP 12345 K 4 85. ‘GBP’ is the manufacturer identification code. I think Grumman used GBM before 1984 and GBP thereafter, but I’m not certain about it. ‘12345’ is the serial number. ‘K’ indicates the month of manufacture (A = January, B = Feb, …). ‘4’ is the last digit of the year of manufacture. Finally, ‘85’ indicates the model year. So GBP12345K485 would indicate a 1985 model year canoe that was built in November of 1984.

Marathon’s current website is somewhat disappointing. But they are a very small operation these days, just 27 employees.

#6

That method works “as long as it works”. I find that it can be too difficult to hold steady enough while holding something as ungainly and heavy as a canoe, so that the scale reading fluctuates a lot. But if you can make it work, it’s the simplest way.

#7

Wow! Great information and suggestions. Based on this input it appears to be the 15’ model with .040" thickness weighing 59#.

It has the later model blue Grumman stenciling midships and without all the detail, the HID is OMCM××××D393.

Everyone was a great help so thanks again!

#8

OK, so built in April 1993 when they were owned by OMC. Have fun.