Conference unifix::sailing

    
    	There is a formular of sorts but I do not know what it is.  It is
    based on beam of boat, oarlock height above water and some other
    factors that I forget.  I tried to get the oar maker to tell me what
    his formular was, no luck.  I did not press him real hard for it maybe
    if I did I would have gotten it.
    
    Forrest

    I have a homemade (by Paul Sears and Evan Suits) 8' dinghy of Phil Bolger 
    design.
    
    His plans call for 6.5' oars. I took an 8' pair and cut them down
    by cutting, boring, dowelling (1"), pinning with 1/4" dowels and
    glueing/filling with polyester resin. They seem to feel about right
    for rowing.
    
    Bill
    
    
    

    For rowing, oars should be about as long as possible. I like 8' on my
    smallest boat, a 12' peapod. I have 9' on my 17' dory.
    
    For storage and handling, especially in a dink, you usually wind up
    with oars sized to fit inside the boat. Wrong reason, and why most
    people think rowing is lousy and buy those damn little outboards.
    
    In one of John Gardners books he has a quote something to the effect
    "if people treated horseback riding like they view rowing, they would
    teach it on water buffalos, and no one would think riding fun". Rowing
    a normal dink, with two short oars, usually placed too low on the
    rail and too close together, makes a lousy trip.
    
    The second thing wrong with most oars, is their construction. The junk
    you buy in boat stores wouldnt make good clubs. The handles are
    shaped wrong- your hands are not barrell shaped, they dont fit on
    barrell shaped handles. Handles should be made cone shaped, with the
    apex toward the blade, large end out. NEVER put any kind of finish on
    an oar handle- only bare wood. Finished handles cause sliding and
    blisters.
    
    Oars should also be counterbalanced. The area between lock and handle
    should be left square, and as large as possible to help ballance the
    blade. Sometimes we even add lead into the loom.
    
    Oars should also be light- ash or oak is about the worst possible
    material. If you intend to use your oars as a general stick or club,
    then oak or ash is ok, but if you intend to row with it, use spruce. My
    better oars have spruce shafts with cedar blades.
    
    Unfortunately, you cant buy a decent oar, you must make them. Shaw and
    Tenny in Maine do a close job, but not quite. Shew and Burnham in S.
    Bristol Maine will make custom oars for not bad prices, but they dont
    stock anything, only make to order, usually with a boat attached :-)
    
    In case you havent guessed, rowing is a hot button for me! It offends
    me to see the usuall dink being yanked across a harbor with the
    misshappen clubs most people have for oars. 
    
    If anyone is interested in good oars look for a book BOATS, OARS AND
    ROWING by Pete Culler, published by Internation Marine. I can also
    expound on oars and rowing at length- although I havent done one of my
    oar making seminars for a few years.

    
    	As if 2 more � is needed-
    	Just like a powerboat makes a lousy sailboat & vice versa, a good
    	pulling shell is no fun with 2 kids/ spouse/ dog/ ice/ baggage/
    	waves/ etc. which all exist out there. The basic flatbottom tou
    	see towed around will come to pretty much a dead stop when you stop
    	pulling for your life- but you can climb aboard your 4-feet-above-
    	water deck with a minumum of teetering. Aso, is a pretty peapod
    	gonna last long on the Vinyard shore in July? Ugly is more secure.
    
    	Scott_who_drools_at_the_wooden_boat_show_but_owns_warped_oars

    I agree a shell would make a lousy tender, but there are many nice
    designs for small boats which will both row and tow well. My 12' Peapod
    is one example, Ive towed it a few hundred miles (behind a Friendship
    sloop) with no trouble, and its a delight to row. 
    
    A pram is about the ugliest possible choice ( I dont even view Zodiacs
    as choices), and wont row or tow worth a damn.
    
    I have no answer to the 'ugly prevents theft' argument. Sadly its
    probably true.

    Ron,
    
    Although this is straying from the basenote I am interested in your
    recommendations for tender designs which both row and tow well.  We are
    considering buying a basic fiberglass shell and finishing it ourselves.
    Suggestions?
    
    Cheers,
    
         Howard

    Shaw & Tenney describes the formula for oar lengths in their catalog.
    I'll post it here when I get a chance.
    
    Lou
    
    P.S. I'm also interested in a discussion of rowing tenders.  I'm
    thinking of building the Catspaw Dinghy or something similar.
    Does Ron have any comments on this design?  Perhaps someone should
    start another note on tenders.
    

    
    re : .8
    
    Since I haven't been inside MIT,I only use to pass by when I was living
    in Cambridge, I 'll ask :-)
    How do you find the lenth with that formula.
    Let's assume X (inboard lenth) = 8 feet
    
    Oar lenth = (8'/7)*25=28.57. Cannot find 28 feet Oar.
    What I do wrong.Before I posted this note I sawed the formula to a
    couple engineers recently graduated from colledge.
    They solve it the same way as I.They only questioned what the inboard
    lenth is?
    Thanx everybody for your help.I do appreciate it.
    I was going to get a 6.5' as it was suggested on one of the notes,but
    I would like to know what lenth the formula of the professionals calls
    for.
    
    

re .8:

Inboard length may refer to the length of oar inboard of the rowlock,
ie, the distance from the rower's hand to the rowlock. This inboard
length might be about half the beam of the dinghy. For a dinghy with
beam of 4', the formula would then give an oar length of (2/7)*25 =
7.1'. This sounds about right. 

There are some tradeoffs regarding oar length. Shorter oars mean shorter 
strokes and more strokes per minute for the same speed (more or less). 
The blades of shorter oars are closer to the water on the back stroke, 
making catching them in a chop much more likely (which is why I need to 
raise the rowlock height on our dingy_rows_tows_and_powers_poorly 
dinghy). Lomger oars may require more strength to row. Our oars are 6' 
and I'd like them to be longer.

Alan

    I think Alan's explanation is correct.  However, I'll check the 
    Shaw & Tenney catalog again and post another note. Sorry to have 
    caused confusion.
    
    Lou

    Here's a formula requiring a less rigorous educational background:
    
    Length of oar = longest dimension of car interior with all doors and
    windows closed.
    
    With my compact car this yields a length of about 6 feet.  The oars
    work very well on my 8.5' pram.  
    
    As a plus, the oars are short enough so that two people sitting 
    abreast can row.  This has to happen when there are four persons in my
    two person rated dinghy.
    
    - gene

    I really hesitated a lot before I posted .8.  As a matter of fact that's
    why I went and ask the college guys just to make sure I do not make
    a complete fool of myself. Because I knew the formula had to be correct
    otherwise Alan would have jumped in  :^)  That's the reason I waited
    so long also. Thanks Alan.If you only knew how much I depend on you..
    
    re: .3 
    
    Ron,
    I cannot afford  that kind of money for oars for a plastic dingy.
    I believe you have a wooden boat,wooden dingy wooden everything.:-)
    Gee.. you must roll in money :-)
    
    
    re: .12
    
    Gene,
    I like your method. As a matter of fact I use similar methods myself.
    That's the reason you read in this file my many questions for help.
    On the other hand people that they see what I actualy do they kind
    look strangely at me. What's the matter with them?
    
    Thanx all again.
    
    P.S. Dingy width appx. 4'  Decision : Buy Oars 6 1/2'-7'. 
    
    
    
    

re: .10

Alan,
	How did you raise the hight of the oarlocks?

	In my dingy with two people and gear, the oars are parallel
	to the water and about 1/4 below the top of my knees!

	Mike

    Re: .13, I dont roll in money, to the contrary, I have all wood things
    because Im to cheap to buy others. My oars cost only about $5 per pair,
    plus a few hours of shop work, which I find very relaxing. All my boats
    are wood, because I build them as well. 
    
    As to raising oarlocks, one method is to make a shaft extension. Ive
    seen rowlocks with shafts of 10-12". You could make a set of extensions
    form old prop shafts, by turning one end to pin diameter, and boring
    the other to fit the lock. These could be brazed to the oar lock. All
    this assumes you have a small machine shop available - doesnt everyone
    :-)
    

    Hi All,
    
    Here's the fully explained formula from the Shaw and Tenney catalog:
    
    	Oar Length = (X/7)*25
    
    	where X equals the Inboard Length (IBL).
    
    IBL is defined as 1/2 the span between rowlocks plus 2 inches.
    So, a boat with a span of 48" would have an IBL of (48/2)+2 or
    26".  The recommended oar length would be (26/7)*25 or about 93".
    
    I would use this as a guide and try to experiment with different
    sizes to see what felt comfortable for you and your boat.  Of course,
    this is not always possible, especially if you are ordering your oars
    via the mail.
    
    The address and phone number for Shaw and Tenney is:
    
    	20 Water Street
    	Orono, Maine  04473
    
    	207-866-4867
    
    

Hi Mike,



>      The dinghy is 8 1/2 ' long and needs a pair of oars.

>    Are there any rules or specks for the lenth of the oars in regard
>    to the dinghy or the rower? 

In the limit condition: long oars are heavy and take energy to lift, 
overcome wind resistance etc.....


In the limit condition: short oars will need to be moved over a wide angle to 
dip them into, and over, the water.


The ideal oar length will let you sway back-and--forth at a comforatable rate;
whilst the dingy is travelling at its best speed.
i.e. you arn't thrasing the waves because you cannot maintain boat speed with 
short oars, etc.
 

So, depending on the taper (and weight distribution) of the oar and how you 
intend to row. (e.g. Shorter oars work bestter in choppy seas) It's up to you.


One practical limitation worth considering.  Can you stow them?  Oars which 
will not stow will eventually become snagged on a warp and be flicked out of 
the boat when your back is turned.  

Advise,  Start with the longest ones you can stow. Try them for a week or so 
then shorted them a few inches. If you find that does not improve them then 
leave them alone.



	Best regards



		Gregg


P.S.   I got axed before Xmas; so unless I find something before March this may
be good-bye.


If you're sailing in Solent waters please call me on channel 16 and  77.  

 "Sandpiper"  

    I have a 9' dinghy (Livingston) and use 8' oars. They are fine.

 re: .17
    
    Hi Gregg,
    
    
    I did have deside between 6 1/2'-7.00' but from the later responses
    I redecided that the oars are going to be at least 7 feet in lenth.
    By the way, I am on the other side of the pond but when I was younger,
    that is much younger,I spent some of the most beautiful months of
    my life in Harwich Essex aboard laid up tramp cargo vessels on Stoor
    River. God bless England and the Queen but I don't believe I'll be in
    in Solent in the near future.Maybe Bahamas....
    Sorry to hear you been " axed". Hope you find something else.
    Wish you the best.
    
    Mike K.