Fifty Pounder rocker

chris pearson

Michigan Canoe Nut
I know I posted on this topic on my last Fifty Pounder restoration. Anyone else notice amount of rocker on Fifty Pounders? This 1937 has about 3”!!!
 

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When that many ribs in a row are replaced, it is hard to keep the bottom from rounding out.
 
Did it very slowly over time and pretty confident I didn’t change that. You know the drill 3 or 4 spaced out over time.
 
Jerry and Andrea at the Island Falls Canoe have an original 15 foot long Old Town form that was used for the Fifty Pound, Lightweight, Featherweight, and Trapper models. I sent them a message about this thread and asked if they could measure the rocker for us. They have very kindly responded as follows.

"Andrea has attached a few photos of our 15' Trapper form. In the long view you can see that the rocker is all located in the ends.

The run along the bottom is perfectly straight until you get to the start of the stem slots. In the closer picture with the level you can see the rapid drop off - or rise if the form was right side up.

By measurement it goes like this. The piece of tape is at the end of the stem slot.

At the second rib from the end the measurement is 1/8"

Rib 4 = 1/2"
Rib 6 = 1 1/8"
Rib 7 = 1 3/4"
Rib 8 = 2 1/2" (often a cant rib)

At this point the curved part of the stem becomes the major factor.

So yes, the rocker is built into the form. But only at the stems.

Cheers,

Jerry

Island Falls Canoe
220 S. Stagecoach Rd.
Atkinson, ME 04426
207.564.7612"


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Well, there’s the proof. Me thinks mine isn’t flat between the stems. Perhaps the 85 years of broken up ribs has relaxed it a little. Not much, but a bit more than original. And thanks a ton for doing this!!
 
If you look at the area from where the stem stops, to the last can’t rib, it really is a significant drop! I wonder the design motive? Definitely more rocker for responsiveness but I’m just curious why they did it in this manner……very interesting.

Jerry and Andrea at the Island Falls Canoe have an original 15 foot long Old Town form that was used for the Fifty Pound, Lightweight, Featherweight, and Trapper models. I sent them a message about this thread and asked if they could measure the rocker for us. They have very kindly responded as follows.

"Andrea has attached a few photos of our 15' Trapper form. In the long view you can see that the rocker is all located in the ends.

The run along the bottom is perfectly straight until you get to the start of the stem slots. In the closer picture with the level you can see the rapid drop off - or rise if the form was right side up.

By measurement it goes like this. The piece of tape is at the end of the stem slot.

At the second rib from the end the measurement is 1/8"

Rib 4 = 1/2"
Rib 6 = 1 1/8"
Rib 7 = 1 3/4"
Rib 8 = 2 1/2" (often a cant rib)

At this point the curved part of the stem becomes the major factor.

So yes, the rocker is built into the form. But only at the stems.

Cheers,

Jerry

Island Falls Canoe
220 S. Stagecoach Rd.
Atkinson, ME 04426
207.564.7612"


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I’m just curious why they did it in this manner

There is no one left alive to ask so we will probably never have a definitive answer. The inspiration for this model is not clear. The information at https://www.wcha.org/forums/index.php?attachments/27616/ indicates that it may have been based on the Charles River model, which would explain the flat bottom. See https://www.wcha.org/forums/index.php?threads/11665/ for more details including the file at http://www.wcha.org/forums/index.php?attachments/24296/ which has a summary of the forms listed in the old inventories. Forms would wear out and be replaced regularly so this could also introduce changes over time.

Benson
 
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