Rich's Question:
I am considering building a Greenland style paddle, but I need to know if there is a specific advantage over the wider bladed paddles. Thanks.

RichJonathan's Answer:
The beauty and gracefulness of a well-made, laminated
Greenland-style sea kayak paddle would by itself justify your project. But there are genuine advantages to the design as well.
A true Greenland paddle has a very narrow, very long blade, with an aspect ratio of seven, eight, even ten to one that is, the blade is seven to ten times as long as it is wide. The shaft is often short enough that your hands ride partially on the shoulders of the blades (thus giving you a constant tactile awareness of blade orientation). A shortened style of Greenland paddle, called a storm paddle, has a shaft sometimes a foot or less in length, and an overall length of six feet or even less. These paddles are designed to be used with a sliding stroke; that is, you slide the paddle through your grip with each stroke, to keep the blade that's out of the water as low as possible.
I find Greenland paddles (or narrow-bladed conventional paddles) to be much more controllable in wind than any fat-bladed design. Many people argue this, pointing out that the total blade area of a Greenland paddle is often the same as a more conventional paddle with a large blade. However, the
Greenland blade is narrow out on the end, where the effects of wind are greatest. With a conventional paddle you've got two large sails stuck on the ends of the shaft.
Greenland paddles, since they are unfeathered, also create less joint stress than a blade that requires extension of the wrist with each stroke. The more I paddle, the less I see a need for feathered paddles for sea
kayaking. I believe their disadvantages outweigh their advantages.
A frequently heard argument against Greenland paddles (by those who have never used them) is that they are poor for rolling due to the narrow design.
This is dead wrong. The high aspect ratio of the blade in fact produces tremendous lift during a roll. Look at the wing of a sailplane, which obviously relies on lift to stay aloft, and note how closely it resembles a Greenland-style paddle! Furthermore, a Greenland paddle seems to be less
sensitive to blade angle during a roll, and doesn't need to be planed on the surface for best effect it works just as well completely submerged.
Of course, there are a few downsides to Greenland-style paddles. They don't offer much support for a slap brace (although they do very well in a low planing brace). And there certainly isn't as much power available for a forward stroke. However, I have never had the slightest problem maintaining excellent daily mileages with a Greenland paddle, and their low stress-factor is a big plus on long trips.
So good luck with your project.