Replies to This Discussion

Permalink Reply by AJ DeRosa on January 9, 2011 at 7:08pm

Something is very wrong here.  Ten foot oars on a small boat like this are not right.  Seven pounds of weight on an oar is a really bad idea.  A boat of this size should row just fine with an oar of 8'-8 1/2' max.  I would suggest that your problem might be the position and height of your rowing seat.  If your seat is very low it might seem that you need longer oars.  Try a few boat cushions on your seat and you might find that a much shorter oar works just fine.

 

While you have my attention with the mention of couterbalancing your way too long oars I am going to ask the forum what they think about adding weight to an oar to make it  "better".  No offense to you Peter,  your question is a very good one and is asked quit often.       Personally I think the idea of adding weight to counter balance an oar is a very, very bad idea with absolutely no benefit whatsoever.  A properly balanced oar is the result of the right right length andd the proper seat position.  Guys who talk about using oars over 9 feet long on any drift boat make me scratch my head in wonder.  Some say it gives them more power but the mechanical advantage goes in the opposite way when you move the fulcrum (oarlock) closer to the power( the rowers hands).  We have three 20' drift boats that carry up to 6 adults and a boatman.  We use 9'oars on these boats and the y row like a dream.

Permalink Reply by Lawrence E. Long on January 9, 2011 at 7:41pm

Peter;  What is the distance between oarlocks  and what is the measurement from the top of the seat to the oarlock?  This might help get some answers.  Whats the height from the oarlocks to the bottom(waterline) 

Good Luck

Permalink Reply by Peter Foster on January 9, 2011 at 11:17pm

The boat specs are:  28" side height gunnel to bottm, 6'-2" beam,  I don't have the exact seat Ht, the boat in storage at a buddies garage.  I can speculate the ht. The rowing seat has a 2" cushion  (not shown) and is approx 12" to 14" below the oarlocks.  I'm 6'-4" tall and the 8' oars we had first barely hit the water. The only way to row w/the 8 footers was to stand up.  Most drift boats I see have much lower sides.

I'll call the bud and get exact dims and repost.

I really appreciate the help. I did find some rough formulas that help predict the oar length but these did not account for the tall sides.  Second pic is daughter rowing on the Clackamas, she is 5'-7".The seat bench is adjustable to slide forward and back but I haven't found that helped. 

 

PS: the botton is only 3/8"plywood, I was thinking another layer of 1/4 or 3/8 or would that be too heavy?  We (the bud) already punched the bottom up once rising on a wave and dropping on a rock.

I'm getting the feeling this Ken Hankinson design is not the greatest, other than light weight- Note there are no vertical ribs in this stressed skin design.

Permalink Reply by Lawrence E. Long on January 10, 2011 at 5:45am

Peter:  I think AJ is right as to the seat height.  The Tracy O'brien 17' guide boat  is about 74" at the locks and the seat is about  6"-8" below the gunwale  and the front of the seat is around 10" from the oarlock.  These dimentions are just looking at the plans here in Maine.  The boat is out in WA  near the Klicitat River at my sons place.  I will call him and get the exact measurements.  This boat uses 9" Sawyer oars and does just fine.    AJ has more time on the river in various boats in a season than most of us get in a lifetime-the long oars are for the white knuckle Grand Canyon guides.

 

Just looking at your pics it seems like the rower is way too deep in the boat- like sitting in the bottom of a claw foot bathtub and trying to  pick up something  off the floor.  Will post more when I hear from the son.

 

Just one mans .02 worth.  Good Luck

Permalink Reply by Riverman on January 10, 2011 at 6:04am

My opinion... Raise the seat height, it looks way too low.

Permalink Reply by Kevin C. on January 10, 2011 at 8:04am

quick and easy solution when you raise the seat,4 pieces attached low on the seat corners with notches for the rails.3 or 4 seat cushions as a tester is the way to go...

Permalink Reply by lhedrick on January 10, 2011 at 8:25am

I am 6 4 also, oars, seat hight etc cause me trouble too.

 

If the seat is too high my knees get in the way when trying to lift the oars out of the water and move them forward.  I raised the locks with raft oar stands bolted to the deck but then 9 foot oars were not long enough and it moved them inside to much.  I moved to lighter composite 9 foot 6 oars and dropped the locks down a bit, re-welded the stands, got them moved out more and that length is working out well.  I am building a new boat with higher sides and have a feeling it will take some tuning when it's done.

 

On a previous boat I used 1 inch wide tapered blocks on the outside of the plywood and then added the out side gunwale.  That moved them out about 1 inch on each side.  More then that sounds like a lot.  My current project will have the oar lock going down through the side material, in the center of the gunwales.   There will be a cutout on the side under the gunwale for the bottom of the oar lock shaft and the pin.  I have 3/8 inch spacers inside and out under the gunwale for the socket drill out so the gunwales will not be touched.  With longer oars I can feel the lose of leverage when the oar locks are inside too far.  The common construction of spacer blocks inside with the locks mounted on them just don't feel right to me.  With 10 foot oars and a few inches of space between the handles it takes some real pull to work that setup.

 

I have been in dories with 10 foot ash oars and for me they are too long and heavy.  

 

 

Permalink Reply by Peter Foster on January 10, 2011 at 10:29pm

Peter here again. I had my buddy measure the seat platform to  gunnel ht.,  it is 13.75".   Our standard 2" boat cushion would raise me up and inch.   I'll build an adjustable ht box to raise the seat 4" to 8"  and see what I get. any body else with some standard seat to gunnel Hts let me know please.  one of my co-owners is 5'-6" so we need to keep it adjustable.

Any comments about the 3/8" ply bottom? too thin??

 

and what a great web site  & forum!!!!!!

Permalink Reply by Lawrence E. Long on January 11, 2011 at 5:17am

Peter:  I would lay on another 3/8" or even 1/2"  on the bottom.  Our sides are 3/8" and the bottom is 3/4"- 1/4" over 1/2"..  Don"t know what your boat weighs but adding to bottom will help stability and mimimize damage from rocks.

Good Luck