double blades in a canoe

[bcelect]

I guess it is the manufacturers that set the length in inches or centimeters. The double blade that was included with the Prism was measured by the seller as 93" I added 24". I can also quickly make another extension of 12" and try either to see which is better. Water test tomorrow.

 

[Guest]

Why does the paddling community talk in terms of centimeters for double blades but inches for single blades? This is the most important question.

Because that is the way they are typically marketed and sold. Why that is so remains the question. Perhaps to better accommodate the European market for kayak paddles?

I got tired of doing the conversions and broke down and bought a tape measure that has both English and metric scales. That tape has become my “notice” that it is time to put away tools and clean the shop before doing any more work.

That” notice” being when it is the only tape measure I can lay my hands on. I still can’t think in metric and doing any kind of carpentry or framing is a nightmare without handy markings at stud centered 16 inch increments (let’s see, in metric that’s 40.6, 81.2 ish, 122, wait, that can’t be right….

I don’t know what forces nixed the conversion to metric in the US, but I’d bet the homebuilding industry was in there somewhere, lest there be a steep learning curve and a lot of miscut studs, cripples and headers.

 

[Guest]

The 25.4mm/in (2.54cm/in) becomes the first thing you really hang onto in real world engineering. It's the bane of the machinist though.

Often times when talking about fits and tolerances the 0.4 gets dropped so that 25 microns (0.025mm)= 1 thousandth of an inch (0.001"). That makes for easy conversions for those stuck in thinking about machine tolerances in inches.

I still do the conversion all the time because my brain thinks of size in inches like many people brought up on English units. But once you do something all the time in SI it gets to the point where you think of things in mm. It still doesn't always have a good tie to reality though... same goes for Newtons of force. That's all we use these days but if I need to relate it to myself I need to convert it to pounds and relate it to my own weight, or the weight of my boat, or something familiar.

 

[Alan Gage]

Before I changed positions at my real job I was about 1 week away from quitting and starting a cabinet shop. I decided that I was going to go all metric. Both ideas have fallen by the wayside now. I did get some metric measuring equipment however and used it for a few jobs. It was kind of a hassle doing the conversions but making up a metric cut list, and then doing the cutting, was great. It made the math so much easier.

Alan

 

[Guest]

I had a piece of specialized (and pricey) plastic cut to size and shape. 3cm thick. What I got was 3mm thick.

When I checked the order it was all on me, I had inadvertently written mm. If I had been ordering inch and a quarter I’d have probably gotten it right.

 

[pblanc]

I had a piece of specialized (and pricey) plastic cut to size and shape. 3cm thick. What I got was 3mm thick.

When I checked the order it was all on me, I had inadvertently written mm. If I had been ordering inch and a quarter I’d have probably gotten it right.

Reminds me of a scene in "Spinal Tap".