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wrote in message
...
On Wed, 30 Apr 2008 14:59:21 -0700 (PDT), wrote:

"Jay" wrote...
1--I've already bought the Suzuki 2.5 hp outboard for our open utility
boat.

2--The boat is 14' 6" long with a 61" beam, 50" bottom width and
approximate 26" side depth.

Not wanting to argue with the Shaw & Tennys formula, but 1.5Xspread
+freeboard is a good starting point. It will be closer to a minimum
for a boat with much weight, if the the oars have even half-decent
balance.

3--In case the ultra-dependable Suzuki should fail or (gasp) run out
of fuel with no more present in the boat, I would have to row the
$#@#$
% thing back to shore.

4--The oars I currently possess are 7' in length and they worked fine
for the dinghy we previously owned.

5--My concern now is that they may be too short with the wider beam
and higher side depth for my monkey arms to maintain a grip on them
while they dip sufficently into the drink and propel us forward.

Is there a guide anywhere that would determine proper oar size (i.e.
length) for an open rowboat that would take into account the
measurements of said rowboat?

Yes.
Have you tried rowing the boat with your oars & the likely load in the
boat? The usual cheesy dinghy oars are likely to break your heart
trying to make any progress rowing. IMHO the reason why so few people
take rowing seriously as a means of practical movement is that so few
have any experience with practical gear.

"Glenn Ashmore" wrote:
Shaw & Tenny has a formula for the proper length for a pulling oar.

Inboard length should be 1/2 the beam between oarlocks + 2"
Total length should be 1/7 the inboard length times 25.

And that's for "pulling boats" most likely, fairly light & low drag,
fairly low freeboard. A good guide especially if Jay is going to the
expense of getting decent oars.

An oar with an efficient blade and good balance is more complicated
than the pole with one end flattened that are usually sold as "oars."
Like all technology, it has developed considerably... the basic
simplicity of the device can be misleading... consider the difference
between different types of hammers, for example.

Assuming your oarlocks are aft of the maximum beam (and make the
calculation
easier) call the distance between oarlocks as 52". Inboard length would
be
26+2 or 28" . 1/7 of 28 is 4" times 25 is 100" = 8' to 8'6" in
standard
lengths. For your maximum beam 9' would probably be better but measure
the
oarlock beam first.. That will put the pull just above waist level.
Much
shorter and the slope gets to steep. You will be pulling up at shoulder
level which in inefficient and uncomfortable. Any longer and it takes
to
much movement to clear the water on the back stroke.

Agreed, but in the absence of high-priced well-balanced oars, too
short by a little is better than too long. And the beam of the boat
matters less than the spread between oarlocks, not quite the same
thing.

At $250/pair a set of 8' spruce Shaw & Tenneys with a good set of
leathers
might be overkill for a working dink but they are a work of art and a
joy to
pull with.

Dunno about "joy" the way most people go to great lengths to avoid
physical exertion... however, they are certainly a heck of a lot more
rewarding than the cheapos from your local discount marine outlet, or
(shudder) those stupid plastic & aluminum things they give away with
inflatable dinks.

Back in the Victorian era, there were quite a number of rowing
cruisers intended for inland waters & rivers; elegant craft with
elaborate tent enclosures and hulls that slipped thru the water
easily. Great for fishing & exploring.

My cousin's husband has a Dovekie. He loves it. Probably rows it more than
he
sails it.

Fresh Breezes- Doug King

I carry two sets of oars for my dinghy. One is a typical short set of
collapsable oars which I use as "backup" when I will be mostly motoring. I
also
find that they are preferable for poking around docks and such. The long
oars
can get in the way sometimes. If I'm really going rowing, I take the long
oars
instead, which really do make a huge difference in my speed and the effort
required to attain it.

If you do not have an outboard engine and only use oars to move your rigid
dinghy you need a good set.
Around here you can buy long oars and cut them to right length and shape to
suit you and your dinghy.
In my case I prefer to make my own oars. I don't save any money but it
give me more flexibility to configure the length and shape to suit the beam
of my dinghy, the oars locks, the size of my hands and the propulsion.
Normally it takes me three dry runs before completing a set. Meaning that I
first use the oars then I adjust them until I am satisfy.