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Jim Redding
03-04-2015, 11:33 AM
I am in the process of building a Cosine Wherry after admiring this rowboat for many years but, until last year, living at a place without room to store the boat. I am almost to the point of taking the hull off the molds, turning it over and starting to work on the inside. Before long I will need to get my oar/oarlock situation in hand and I am reading up trying to understand what would be best regarding oar length, oar lock types, etc. I have read a bunch of forum threads on these subjects and see that there is a range of opinion, not surprisingly.

One experienced Cosine Wherry rower I talked with has recommended that I use caged sculling type oar locks and D shaped, feathering sculling type oars long enough to row cross handed like sliding seat rowers do. I own a pair of 9'-9" spruce sculling oars, which seem a little long for a Cosine Wherry, though they have the advantage of my already owning them. I understand that using these long oars on this 4'-4" beam wherry would only be possible by cross handing. While I believe that rowing cross handed rowing would probably work well in calm water, I am planning to row my boat in choppy as well as calm water and I am wondering if cross handed would be problematic in chop. I know that most people seem to favor horn type oar locks over Douglas or sculling oar locks for fixed seat rowing but I haven't read much informed opinion about cross hand rowing on rougher water than sliding seat sculling is usually done on.

After the time and energy I am putting into building this boat and after admiring the Cosine Wherry for twenty years, I want to use oars and oar locks that are really appropriate for the boat and conditions and won't use my long sculling oars just because I have them if they really aren't right. I am wondering what opinions any experienced fixed seat rowers might have about this idea of cross handed rowing of a Cosine Wherry in the salt water around Anacortes, Washington.

Gerarddm
03-04-2015, 11:55 AM
Thorne is very knowledgable, having owned one for years. Hopefully he will chip in, or perhaps you can PM him.

Rick in Pender Harbour
03-04-2015, 12:08 PM
I row mine with 8 foot oars and ring oarlocks. I had some 9 footers and Douglas locks, but found the balance off, and the extra load was hard on the arms. I don't row cross-handed unless I'm in the forward or aft rowing positions. My friend, uses 9 foot spoon blades on his wherry, with ring locks and I think that he finds that about right for him unless he is against a headwind, wen he changes to to 8's. I seem to be able to keep up with him. I recommend 8's from barclay sound oar to my clients as they work well and are easy to get here in either straight or spoon blade.
Best rgds

Rick

oysterbayboats

Ben Fuller
03-04-2015, 12:12 PM
Since the pins for the D oars and pins for other oar locks all are the same size, there is nothing that keeps you from dropping some in and seeing how you like it. The open topped D locks found on Ocean shells may be a little easier to handle. You can then always make a second set of oars......

Seriously the spread on a single scull is pretty much 60 inches which gives a handle over handle overlap. The only folks I know that go much more than that are the Adirondack guide boat rowers. You may be able to adjust the collars on your single scull oars to the handle over lapped standard which works pretty well, because height off the water also affects things; you are higher than a single scull. An example, I have a 60 inch spread in my Harrier, and hoped to use my 9'6" sculls, but they were too short because of the height off the water.

John DeLapp, designer of the Cosine probably has some recommendations. My guess is that you will find that 8 footers will give you handle over handle overlap which I find just fine for open water.

Jim Redding
03-04-2015, 02:08 PM
Thanks for the feedback, guys.

asloth
03-04-2015, 08:00 PM
Jim, if you are interested in building your own oars, here's building instructions for oars John DeLapp designed. I've built many pair and they are a very good design. http://www.tsca.net/puget/resources/oars/delapp_spoon_oars.html

Steve C.
blindeyeboats

Jim Redding
03-04-2015, 11:04 PM
Thanks, Steve. Interestingly, I was just looking at this oar design a couple of days ago. I was thinking, the shafts being only 1-11/16" thick, that these might be pretty springy if you made them longer. How long have you made oars by this design? Did you use spruce like John DeLapp specified? Have you made any longer than his 7'-6"? Did you have to add thickness? Or they might be made from Douglas fir to stiffen them, I guess. One thing for sure, these would be a lot easier to make than carving out the spoons the old fashioned way. How do they look?

asloth
03-04-2015, 11:46 PM
Jim, Briefly I"ve built John's designed oars from redwood, shelving pine, and Doug. Fir. Haven't broken a one yet. And yes, I"ve lengthened them to near 8', but usually keep them to the designed 7'6". And I've taken some liberties w/ John's dimensions for looms and blades. My latest pair have epoxied 2X3mm. blades w/ very skinny Doug. Fir looms. Used lumber yard D.F w/ a few knots. I'll try to post a pic or two.
BTW: will you be attending the PT Palooza in July of this year? Should be lots or oars there.
SteveC.
blindeyeboats

Jim Redding
03-05-2015, 12:16 AM
Thanks for the info, Steve. I would like to see some pictures of your oars. Hard to say if I will make it to PT this year. It is always worth ones while, for sure.

James McMullen
03-05-2015, 12:33 AM
I wouldn't want oars that long. I think 8 or 8-6 is a better fit in that boat for open water. I also think you'll want relatively narrow blades and round looms with open top oarlocks, not D's and sculling type oars. Smooth water rowing is a different animal. A lot of that flatwater stuff is just plain uncomfortable when you're rowing in the chowder.

Jim Redding
03-05-2015, 09:54 AM
Thanks, James. What is Rowan's spread at the oar locks? What length of oars do you typically use in open water? Do you row with any handle overlap?

James McMullen
03-05-2015, 10:55 AM
Rowan is 5-4 at the locks. I use relatively short 9-6 oars, with long leathers with plenty of adjustment inboard and out so that I can vary the leverage and balance at will. I do not row against the buttons, nor do I feather my oars unless necessary. Typically, I will row with about a half-hand overlap when I'm chugging along for the long haul.

This is all somewhat contrary to smooth-water, go-fast, short-duration rowing practices, but that's not really what I'm all about in Rowan. I do enjoy rowing in a fast flatwater shell once in a while for contrast, I must admit. But the techniques in open water require a somewhat different focus.

Thorne
03-05-2015, 12:18 PM
John DeLapp designed the Natoma Skiff, a very nice variation of the Herreshoff Rowboat, not the Cosine. His oars are great for uber-light pulling boats, but not for uses like pushing off rocks, docks or mudflats. If I was cruising the San Juans I might be tempted to use heavier straight-blade oars rather than the DeLapp or standard spoons, with standard "Y" oarlocks and leathers with collars.

DeLapp oars in a DeLapp boat on Lake Natoma many years ago -
https://farm8.staticflickr.com/7434/9648396158_a0ff86314d_b.jpg

I've tried various length oars in my Cosine, and find they work better for certain types of rowing. For calm water (as would be experienced in most sculling races) the longer oars ( 9'10" carbon fiber looms are the longest I own) **seem to me** to provide a bit more speed. As the wind and swell pick up, shorter oars (8'6' or 8') work better and catch fewer crabs. And this is rowing mostly from the center position, not cross-handed.

8'6" spoon oars on Richmond Inner Harbor (rowing into a rainstorm - DOH!)
https://fbcdn-sphotos-c-a.akamaihd.net/hphotos-ak-xfa1/v/t1.0-9/q85/s720x720/1509299_10152423143028646_84824103_n.jpg?oh=61f2cd 5de756299a60b7e7a9bccccd54&oe=55783C70&__gda__=1434406462_c22c7a33c0a3b84c2dda1158ec93e24 1

Being a lazy rower and not a purist, I often use the Douglas oarlocks with home-made leather "D"-shaped pads and collars. These hold the oar at the best angle, but usually don't allow feathering / dory-stroke / etc. They are also **very difficult** to get oars in and out of, requiring you to pull the oar right up to the neck above the blade before you can squeeze the wood through the gap between oarlock tips.

(Newly-made and in use on my Chamberlain Dory Skiff on Lake Sonoma) -
http://www.luckhardt.com/douglas_lock1.jpg

Jim Redding
03-05-2015, 01:35 PM
James and Thorne,
Thank you, your comments are very helpful.

Eric Hvalsoe
03-05-2015, 01:39 PM
Your 9 9's would have to sit on outriggers to use even cross handed on a cosine. My boat is 4' 6" and I use 8's, no overlap. If I wanted overlap maybe I would use 8'6". I think overlap is mostly a matter of habit and preference. I understand there is a mechanical argument for it. I use narrowish spoons, all conditions. They are sensitive to angle of attack. Round looms. I do feather against appreciable head or crosswind. D might be handy for that, have not tried them on my sail and oar boat. No captured oarlocks.
Really long oars are awkward in the chowder zone.

Ben Fuller
03-05-2015, 02:09 PM
The mechanical issue is really a biomechancial issue. Idea is to keep the pull inline with shoulders or inboard as much of the stroke as possible. If hands are a shoulder width apart at the catch they will overlap mid stroke, then out again.

Jim Redding
03-05-2015, 10:05 PM
Thank you all for your comments. These were just the kind of perspectives I was after.

Eric Hvalsoe
03-06-2015, 10:36 AM
The mechanical issue is really a biomechancial issue. Idea is to keep the pull inline with shoulders or inboard as much of the stroke as possible. If hands are a shoulder width apart at the catch they will overlap mid stroke, then out again.

To tell the truth ben I got used 8's in this boat because they are a locally available off the shelf good quality, good value oar. I'm used to rowing with overlap in other sliding seat vehicles. The next boat maybe I'll make a pair with overlap.

Jim Redding
04-09-2015, 12:10 AM
Rick,
I have another Cosine Wherry question for you, if you don't mind. Since you build them professionally, your opinion about this would be as good as they come. I am at the stage of being about to glue 8'-6" stringers inside the hull to set the ends of the thwarts on and I am wondering whether I need to screw through the hull into the stringers or if just epoxying them on would be sufficient. Bob and Erica Pickett of the former Flounder Bay Boat Lumber in Anacortes, who published the original how to build the Cosine Wherry book back in the '80s, are still in Anacortes and have the second Cosine made. I talked to Erica about this and she said that way back when, she and Bob just didn't trust the epoxy to do the job without the screws being there too and that is why they said to screw through the hull in their Cosine Wherry book. But I really don't want to put holes through the hull. I have steam bent the stringers to take the "bind" out of them when glued on. What do you think about this issue? Do you epoxy and screw the thwart stringers on the Cosines you build? If you epoxy only, have you ever seen delamination happen?

Jim Redding
Anacortes, WA

Thorne
04-09-2015, 09:27 AM
Jim - I didn't build my Cosine but did restore it and replaced / repositioned the thwarts. The stringers are both glued and screwed, and the screw head placement is visible since the hull is finished bright inside and out. I suspect that glue would be enough, depending on how hard you row & use the boat.

Here's the thread on shifting the thwarts around based on my (and my wife's) weight. It worked very well, and I've taken both heavy and light passengers in the stern sheets when rowing from the forward thwart -
http://forum.woodenboat.com/showthread.php?88766-Cosine-Wherry-repositioning-thwarts-for-1-rower&highlight=thwarts

http://www.luckhardt.com/launch_test3.jpg

https://farm8.staticflickr.com/7641/17088058271_daba90c3b5_b.jpg

Jim Redding
04-09-2015, 09:55 AM
Thanks for the feedback, Thorne

Thorne
04-09-2015, 11:31 AM
Sure. Here's what I'm suggesting you consider -- finishing the boat with sternsheets and risers, but not oarlock bases or thwarts. If it won't be visible, tape or mark the waterline.

If you'll have a "usual" passenger in the stern, put that person there, and sit yourself on a movable box. Get someone to take photos from a dock or another boat. Shift the box to the forward rowing position, then to the center. See how the boat levels out -- you want a slight bow-up position in most cases. If you plan for two rowers and a possible passenger / cox, try another person on a box.

That way you don't rely on the designers guess / averaging on crew weights - you'll **know**. As you can see from the thread, I found the designer's thwart location to be a bit off, but then again I'm a lot heavier than my wife... ;-)

Rick is the pro builder so I'd go with his recommendations for sure. I'm just sharing my experience with this one Cosine.

Jim Redding
04-10-2015, 10:41 AM
Thorne,
I have read your previous thread on repositioning the thwarts with interest. In fact, I have read all of your Cosine Wherry threads with interest. When I first started building my boat, it occurred to me that I might tune it for my and my wife's weight difference and I originally intended to do that. But in thinking about it further, I decided to go with the designer's guess/average on crew weights. My reasoning is this:

It is my understanding that this boat was designed for two 200 pound rowers to put it on the design water line. I have about 45 pounds or so on my wife. The boat will mostly be crewed either by both of us rowing tandem, with us sitting on the fore and aft thwarts, or by either of us alone in the boat sitting on the center thwart. With us both rowing, it would certainly be ideal for the boat to be tuned for the 45 pound weight difference between us. However, this combination of she and I rowing will not be the only combination of people who I expect will row this boat. If the thwarts are positioned as designed, with her sitting fore and me aft, the boat would be somewhat stern down. It probably won't be unbalanced dramatically though and stern down is better than stem down. In contrast, if the thwart positions are such that it is perfectly balanced for us, it would ride stem down if rowed by two people with less weight contrast than my wife and me. This strikes me as making the boat less flexible. It seems to me like the boat would be best situated so that any two people could sit on the fore and aft thwarts without putting the boat stem down.

Jim Redding
04-10-2015, 11:05 AM
Incidentally, if anyone was interested in my question to Rick in Pender Harbour, BC about gluing and screwing the thwart stringers, versus epoxying them on only: I private messaged Rick in case he didn't notice my question to him in the thread. He told me that he epoxies only on the Cosine Wherries he builds and has not had a problem with that.

Jim Redding
04-11-2015, 10:08 AM
Thorne,
Did you find anything wrong with the designer's original position for the center thwart? According to thr original design, the center thwart is 10" wide with the aft edge of it located 86" from the leading edge of the plywood stem. In your finished boat, the stem will be buried way under the small deck but you must have estimated its position fairly accurately when you were measuring everything for your thwart repositioning. Did you end up positioning the center thwart significantly different from the design position?

I expect that there are subtle differences in hull shape between different Cosine Wherries and so differences in where the center of floatations falls. Not only did the strips spring out away from the molds to a certain extent during my stripping processs but I found that the #2 and #10 station molds as shown in the original plans were just wrong. I had to alter both of these molds a fair bit in order to get a fair hull. I suspect that different builders have dealt with these two wrong mold designs in different ways and come up with slightly different hulls. The pictures in the original Cosine Wherry book-Rip, Strip and Row - show the boat being built without even using the #1 station mold. I understand that because I found that the designed #1 and #2 molds as shown in the plans would make for a wasp wasted bow and I had to make the #2 mold larger.