Oar Length Formula

In the process of gearing up for this summer, I've been trying to educate myself as much as possible about aquatics skills and aquatics equipment. I think I mentioned in an earlier post that rowing is probably the one with which I'm most unfamiliar. Today, however, I've managed to learn something new about rowing.

A review of our equipment inventory revealed that we currently have only eleven 7-ft oars, one (yes, one) 7.5-ft oar, and six 8-ft oars (though two of them look questionable, and I'd rather not use them). That means that we can put only seven fully-equipped row boats in the water, with only one spare 7-ft oar. Pretty scary.

So the camp needs more oars. The problem, however, is what length of oar we are supposed to get. No one seems to know what the proper oar length is for our rowboats.  I know from reading the Rowing Merit Badge pamphlet that oar length is a function of the distance between the oarlocks, but it doesn't get much more specific than that.

The best lead I got was from Jim, who said that oar length is governed by something the Red Cross used to call "Van Claussen's formula." So I tried to search for it on Google. No dice. But I did find that there was a 1956 canoeing book that was published by the Red Cross and written by W. Van B. Claussen, and I also found that the UW had it in its libraries. I picked it up this morning, and what to my wondering eyes should appear, but information and diagrams about rowing and proper oar length.

Here are the results of my research:

So there it is, simple and elegant. There needs to be a leverage ratio of 7:18 between the inboard and outboard oar lengths. Where x is the distance between the oarlocks, the oar length should [(x/2) + 2] (25/7). The formula does ask for the oars to overlap by four inches in the middle, but it's easy to recalculate if one wants to hold the oars with the grips just touching one another, as Jim prefers.

I don't know off hand what the precise beam of our rowboats is.  My guess, however, is that it's about 60 inches, which means that we should be using oars that are around eight feet in length. This confirms my own suspicion that our 7-ft oars are too short. Granted, my rowing knowledge has been limited so far, but they nevertheless did feel pretty weak to me when I used them. Regardless, Gary Smith, our in-house rowing aficionado, will be going in a rowboat this weekend to test our oars and find out what works for him, and we'll see if this formula holds up empirically. So stay tuned for the results of this experiment (I know this just has you all on the edge of your seats)...