oar block placement, help please!!

[Bob at Compass Boat]

Hi,

Finally getting close to finishing up my cosine wherry. Hope to be in the water by May. Ready to install cap rails and oar blocks. My question is what is proper placement of oar blocks? Thought I read somewhere(can't find info now) that oar blocks should be sized and located so that the oar locks are 6" higher then the thwart they serve and 10"-12" forward of the leading edge of that thwart. Would appreciate any input on this. Thanks in advance.

Bob V.

[John Bell]

The rule of thumb I use is when the oars are held parallel to the surface of the water, their handles should be at the same height as the rower's belly button.

They should also be 10-12" aft of the aft edge of the thwart they serve.

[Bruce Hooke]

The height above the thwart sometimes ends up being a compromise to keep the thwart from getting too close to the bottom of the boat.

[reinbilt]

Bob,

I'm building the same boat and am also about ready to install cap rail, blocks, and inwalls.
My copy of Rip, Strip, and Row show the center of the oarlock blocks 12 inches from the edge of each seat. If you have this book did you find it as vague as I did? Good luck with the finish work on your wherry.

reinbilt

[Paul Scheuer]

I'll vote for temporary, test pads, clamped in place. It'll get you in the water sooner.

[John B]

somebody who knew what they were talking about once posted here that the rowlocks should be the length of your forearm from the crook of your elbow to the ball of your thum back from the aft edge of the thwart.I can't remember who .It seems like a reasonable method and would seem to be around the 10 to 12 inches on average . I always thought about a foot was the rule so... near enough. I've tried to search for it( I asked the question myself) but can't find it.

[Paul Reagan]

I'm pretty familiar with the subject and have always used the rule of thumb that the locks should be the same distance as that "from the crook of the elbow to the crook of the wrist". John Gardner himself told me this.
As we humans are anthropometrically similar, this generally comes to about 9 3/4". Obviously, a very short person might go to 9" or a very tall person to 10 1/2' but 9 3/4' should be good for most rowers.

[Bob at Compass Boat]

HI Guys,

Thanks for the help. I am planning on selling the boat as soon as it is done. The new owner is a small person so the 9"-!0" might be good. Used a home made guide yesterday, a six inch heighth above the thwart makes for a VERY HIGH BLOCK on the center thwart where the shear line is low. Going to check 4'-5". When all is said and done will post some pictures. I won't say how long I have been working on this boat.

Bolb V

[Chuck Cannon]

I launched my cosine wherry last spring and was able to row nearly every day last summer, both alone and with another also rowing. I found that with riser block of two inches worked very well with 9 foot oars and the thwarts on raisers as per plans and 12 inches from aft edge of thwart to oarlock, but the aft blocks are closer together and the thwart seems too far aft. I plan to move the after thwart foreward about 4 inches, not wanting to place the oarlocks any further aft, and also install small knees under the aft riser blocks as they flex a bit when rowing from that position. I am 5' 10'' with forearm length of 11". I must say that I love the way this little boat rows, handles and looks! Good luck with yours!

Chuck

[Frank E. Price]

I'd go with Paul Scheuer's suggestion, with the buyer in place. Don't forget that on the back stroke, when the oar handles are at their lowest, they have to clear your thighs and knees. So if you've lowered the thwart to provide more clearance, you may be aggravating the problem by raising your knees. And I usually register my butt on the forward edge of the thwart, so the measurement of interest in that case would be from the forward edge to the oarlock. But if it's a very wide thwart (10 1/2" in my sharpie skiff), you don't row on the forward edge.

Best way to locate it for sure is to try it clamped down. Then you don't tear your hair out when it's less than tolerable.

Frank