Determining Oar Length

[TimH]

How do you determine what length of oar to get for a particular user/boat ? I have always used what I had (my great grandfathers oars) and never paid attention to length. I am thinking of buying a set of oars from here Fancy's (http://stores.ebay.ca/Fancys-Oars-and-Paddles_W0QQsspagenameZL2QQtZkm)
http://i12.ebayimg.com/03/i/02/56/01/77_1_b.JPG
They have 7', 8', and 9' lengths, solid one-piece spruce. Seems like good prices too.

[TimH]

How do you determine what length of oar to get for a particular user/boat ? I have always used what I had (my great grandfathers oars) and never paid attention to length. I am thinking of buying a set of oars from here Fancy's (http://stores.ebay.ca/Fancys-Oars-and-Paddles_W0QQsspagenameZL2QQtZkm)
http://i12.ebayimg.com/03/i/02/56/01/77_1_b.JPG
They have 7', 8', and 9' lengths, solid one-piece spruce. Seems like good prices too.

[TimH]

How do you determine what length of oar to get for a particular user/boat ? I have always used what I had (my great grandfathers oars) and never paid attention to length. I am thinking of buying a set of oars from here Fancy's (http://stores.ebay.ca/Fancys-Oars-and-Paddles_W0QQsspagenameZL2QQtZkm)
http://i12.ebayimg.com/03/i/02/56/01/77_1_b.JPG
They have 7', 8', and 9' lengths, solid one-piece spruce. Seems like good prices too.

[Dave Fleming]

Geeze up there with all that good wood and Smalser just across on the ferry and over the bridge and you cannot make your own oars.......?????

Jes' funnin' ye lad.

Seriously, make a set fer yer self!

[ 09-03-2004, 02:46 AM: Message edited by: Dave Fleming ]

[Dave Fleming]

Geeze up there with all that good wood and Smalser just across on the ferry and over the bridge and you cannot make your own oars.......?????

Jes' funnin' ye lad.

Seriously, make a set fer yer self!

[ 09-03-2004, 02:46 AM: Message edited by: Dave Fleming ]

[Dave Fleming]

Geeze up there with all that good wood and Smalser just across on the ferry and over the bridge and you cannot make your own oars.......?????

Jes' funnin' ye lad.

Seriously, make a set fer yer self!

[ 09-03-2004, 02:46 AM: Message edited by: Dave Fleming ]

[TimH]

I would make my own, but first I have to build a shaving horse, buy a drawknife, buy some spruce, and find the time to make them. The woodenboat festival is next weekend. I want to be able to row out and look at the boats :D

http://www.woodenboat.org/regattas/boats_of_pt_bay/shipw04_sharonedwards.jpg


I found the formulas though anyway. Here they are:

Oar Length Formula
~ For Correctly fitted oars ~
* The span of your boat between oar locks.
* equals one half the span of your boat between oar locks + 2 inches, on center of the oar lock socket holes.
~ ~ ~ ~ ~ ~ ~
In short; take the span of your boat between oar locks, divide by 2 and then add 2 inches to that total.
Then, divide by 7.
Then, multiply by 25.
This gives you the length of oar in inches.
Optionally, dividing your oar length inches by 12 will give you an answer in feet.
~ ~ ~ ~ ~ ~ ~

The leverage ratio is 7:18.
Total length of the oar equals one-seventh of the inboard length multiplied by 25.

Distance to the center of the oar leather from the end of the grip equals 7/25 of the total length of the oar.

http://www.shawandtenney.com/oar.jpg

[ 09-03-2004, 03:34 AM: Message edited by: TimH ]

[TimH]

I would make my own, but first I have to build a shaving horse, buy a drawknife, buy some spruce, and find the time to make them. The woodenboat festival is next weekend. I want to be able to row out and look at the boats :D

http://www.woodenboat.org/regattas/boats_of_pt_bay/shipw04_sharonedwards.jpg


I found the formulas though anyway. Here they are:

Oar Length Formula
~ For Correctly fitted oars ~
* The span of your boat between oar locks.
* equals one half the span of your boat between oar locks + 2 inches, on center of the oar lock socket holes.
~ ~ ~ ~ ~ ~ ~
In short; take the span of your boat between oar locks, divide by 2 and then add 2 inches to that total.
Then, divide by 7.
Then, multiply by 25.
This gives you the length of oar in inches.
Optionally, dividing your oar length inches by 12 will give you an answer in feet.
~ ~ ~ ~ ~ ~ ~

The leverage ratio is 7:18.
Total length of the oar equals one-seventh of the inboard length multiplied by 25.

Distance to the center of the oar leather from the end of the grip equals 7/25 of the total length of the oar.

http://www.shawandtenney.com/oar.jpg

[ 09-03-2004, 03:34 AM: Message edited by: TimH ]

[TimH]

I would make my own, but first I have to build a shaving horse, buy a drawknife, buy some spruce, and find the time to make them. The woodenboat festival is next weekend. I want to be able to row out and look at the boats :D

http://www.woodenboat.org/regattas/boats_of_pt_bay/shipw04_sharonedwards.jpg


I found the formulas though anyway. Here they are:

Oar Length Formula
~ For Correctly fitted oars ~
* The span of your boat between oar locks.
* equals one half the span of your boat between oar locks + 2 inches, on center of the oar lock socket holes.
~ ~ ~ ~ ~ ~ ~
In short; take the span of your boat between oar locks, divide by 2 and then add 2 inches to that total.
Then, divide by 7.
Then, multiply by 25.
This gives you the length of oar in inches.
Optionally, dividing your oar length inches by 12 will give you an answer in feet.
~ ~ ~ ~ ~ ~ ~

The leverage ratio is 7:18.
Total length of the oar equals one-seventh of the inboard length multiplied by 25.

Distance to the center of the oar leather from the end of the grip equals 7/25 of the total length of the oar.

http://www.shawandtenney.com/oar.jpg

[ 09-03-2004, 03:34 AM: Message edited by: TimH ]

[Dave Fleming]

So ya snuck out and visted Shaw and Tenney did ya?

Aside from Pete Culler probably best ye could do.

AND it is 12:PM out here! Why are you, a working fellow still up????

insert big grin here

[Dave Fleming]

So ya snuck out and visted Shaw and Tenney did ya?

Aside from Pete Culler probably best ye could do.

AND it is 12:PM out here! Why are you, a working fellow still up????

insert big grin here

[Dave Fleming]

So ya snuck out and visted Shaw and Tenney did ya?

Aside from Pete Culler probably best ye could do.

AND it is 12:PM out here! Why are you, a working fellow still up????

insert big grin here

[TimH]

I am stuck on night shift hours. I am going outside to work in my shop right now ;)

What may I ask are *you* doing up at this hour? tongue.gif

[ 09-03-2004, 03:30 AM: Message edited by: TimH ]

[TimH]

I am stuck on night shift hours. I am going outside to work in my shop right now ;)

What may I ask are *you* doing up at this hour? tongue.gif

[ 09-03-2004, 03:30 AM: Message edited by: TimH ]

[TimH]

I am stuck on night shift hours. I am going outside to work in my shop right now ;)

What may I ask are *you* doing up at this hour? tongue.gif

[ 09-03-2004, 03:30 AM: Message edited by: TimH ]

[Andrew Craig-Bennett]

Wow, what a complication!

Not saying it's wrong, but, frankly, for a dinghy:

1. How long a pair of oars can you stow in the boat? Keep in mind that two oars take more space than one, and that, if the dinghy is a tender, and is towed, it is desirable to be able to jam the oars under the centre thwart with their ends inside the gunwales, so they don't jump out under tow.

2. On that basis, make or buy the longest pair of oars that you can manage.

3. Use them before you leather them; that way, you will know where to put the leathers.

4. As Pete Culler points out, if you can row with oars crossed, that's better.

[Andrew Craig-Bennett]

Wow, what a complication!

Not saying it's wrong, but, frankly, for a dinghy:

1. How long a pair of oars can you stow in the boat? Keep in mind that two oars take more space than one, and that, if the dinghy is a tender, and is towed, it is desirable to be able to jam the oars under the centre thwart with their ends inside the gunwales, so they don't jump out under tow.

2. On that basis, make or buy the longest pair of oars that you can manage.

3. Use them before you leather them; that way, you will know where to put the leathers.

4. As Pete Culler points out, if you can row with oars crossed, that's better.

[Andrew Craig-Bennett]

Wow, what a complication!

Not saying it's wrong, but, frankly, for a dinghy:

1. How long a pair of oars can you stow in the boat? Keep in mind that two oars take more space than one, and that, if the dinghy is a tender, and is towed, it is desirable to be able to jam the oars under the centre thwart with their ends inside the gunwales, so they don't jump out under tow.

2. On that basis, make or buy the longest pair of oars that you can manage.

3. Use them before you leather them; that way, you will know where to put the leathers.

4. As Pete Culler points out, if you can row with oars crossed, that's better.

[TimH]

According to that formula my oars should be 6.95 feet long. According to the formula in West marines catalog they should be 42.625/2 X 3 + 6 = 5.8 feet

I think I'll get 8 footers :D

[TimH]

According to that formula my oars should be 6.95 feet long. According to the formula in West marines catalog they should be 42.625/2 X 3 + 6 = 5.8 feet

I think I'll get 8 footers :D

[TimH]

According to that formula my oars should be 6.95 feet long. According to the formula in West marines catalog they should be 42.625/2 X 3 + 6 = 5.8 feet

I think I'll get 8 footers :D

[Andrew Craig-Bennett]

Personally, I like longer oars, so I'd go with the 8 ft!

[Andrew Craig-Bennett]

Personally, I like longer oars, so I'd go with the 8 ft!

[Andrew Craig-Bennett]

Personally, I like longer oars, so I'd go with the 8 ft!

[Jon Etheredge]

I would make my own, but first I have to build a shaving horse, buy a drawknife, buy some spruce, and find the time to make them.
A couple of comments:

1) Yeah, I bet a shaving horse would be nice. But I haven't ever used one for making any of the dozens of pairs of oars I've built. Use a saw horse or the top of a workbench or anything you've got handy.

Use a plane or spokeshave if you don't have a drawknife.

Use fir, ash, sassafras, cedar or whatever you've got laying about or can easily obtain.

The pictures that you've posted of your work show that you do nice work. So get out there and whip up a set of oars smile.gif

2) Be careful about arbitrarily increasing the length of the oars. The 7:18 inboard to outboard ratio of the Shaw and Tenney formula is effectively the "gear ratio" of the oars. If your oars are too long for the distance between the 'locks, you'll end up with too little inboard and the oars wil be very hard to pull and tiring to use.

I'm not saying that the 8' oars won't work. I am only saying that you should consider your choice carefully.

[Jon Etheredge]

I would make my own, but first I have to build a shaving horse, buy a drawknife, buy some spruce, and find the time to make them.
A couple of comments:

1) Yeah, I bet a shaving horse would be nice. But I haven't ever used one for making any of the dozens of pairs of oars I've built. Use a saw horse or the top of a workbench or anything you've got handy.

Use a plane or spokeshave if you don't have a drawknife.

Use fir, ash, sassafras, cedar or whatever you've got laying about or can easily obtain.

The pictures that you've posted of your work show that you do nice work. So get out there and whip up a set of oars smile.gif

2) Be careful about arbitrarily increasing the length of the oars. The 7:18 inboard to outboard ratio of the Shaw and Tenney formula is effectively the "gear ratio" of the oars. If your oars are too long for the distance between the 'locks, you'll end up with too little inboard and the oars wil be very hard to pull and tiring to use.

I'm not saying that the 8' oars won't work. I am only saying that you should consider your choice carefully.

[Jon Etheredge]

I would make my own, but first I have to build a shaving horse, buy a drawknife, buy some spruce, and find the time to make them.
A couple of comments:

1) Yeah, I bet a shaving horse would be nice. But I haven't ever used one for making any of the dozens of pairs of oars I've built. Use a saw horse or the top of a workbench or anything you've got handy.

Use a plane or spokeshave if you don't have a drawknife.

Use fir, ash, sassafras, cedar or whatever you've got laying about or can easily obtain.

The pictures that you've posted of your work show that you do nice work. So get out there and whip up a set of oars smile.gif

2) Be careful about arbitrarily increasing the length of the oars. The 7:18 inboard to outboard ratio of the Shaw and Tenney formula is effectively the "gear ratio" of the oars. If your oars are too long for the distance between the 'locks, you'll end up with too little inboard and the oars wil be very hard to pull and tiring to use.

I'm not saying that the 8' oars won't work. I am only saying that you should consider your choice carefully.

[Bob Smalser]

Frankly...

...I tend to make them to fit the available storage space, often the determining factor.

I also have a narrow beam work punt that requires rowing with crossed hands....a real comfortable and powerful technique once you get used to it.

[ 09-03-2004, 10:49 AM: Message edited by: Bob Smalser ]

[Bob Smalser]

Frankly...

...I tend to make them to fit the available storage space, often the determining factor.

I also have a narrow beam work punt that requires rowing with crossed hands....a real comfortable and powerful technique once you get used to it.

[ 09-03-2004, 10:49 AM: Message edited by: Bob Smalser ]

[Bob Smalser]

Frankly...

...I tend to make them to fit the available storage space, often the determining factor.

I also have a narrow beam work punt that requires rowing with crossed hands....a real comfortable and powerful technique once you get used to it.

[ 09-03-2004, 10:49 AM: Message edited by: Bob Smalser ]

[Steve Lansdowne]

I used the formula that TimH gave, which is what Shaw and Tenney recommend, for my Whisp, and came up with 6 1/2 footers, which turned out to be too short. I'm going with 7 footers, which is what the designer suggests (though I didn't learn this until I had already bought some very nice 6 1/2' oars). I suggest that you try out a given length before buying expensive oars that size. My too-short oars kept popping out of the locks. If I had them overlap, then the outboard length seemed too short.

[Steve Lansdowne]

I used the formula that TimH gave, which is what Shaw and Tenney recommend, for my Whisp, and came up with 6 1/2 footers, which turned out to be too short. I'm going with 7 footers, which is what the designer suggests (though I didn't learn this until I had already bought some very nice 6 1/2' oars). I suggest that you try out a given length before buying expensive oars that size. My too-short oars kept popping out of the locks. If I had them overlap, then the outboard length seemed too short.

[Steve Lansdowne]

I used the formula that TimH gave, which is what Shaw and Tenney recommend, for my Whisp, and came up with 6 1/2 footers, which turned out to be too short. I'm going with 7 footers, which is what the designer suggests (though I didn't learn this until I had already bought some very nice 6 1/2' oars). I suggest that you try out a given length before buying expensive oars that size. My too-short oars kept popping out of the locks. If I had them overlap, then the outboard length seemed too short.