Re: Yuloh's and salient keels [was]

Thank you Peter; that was the place. As to be expected with Bolger,
'salient' used meaningfully.

cheers
Derek
> 1.. A military position that projects into the position of the
enemy.

e.g. The Battle of the Bulge.

Peter
sa·li·ent (sa'le-?nt, sal'y?nt)
adj.
1.. Projecting or jutting beyond a line or surface; protruding.
2.. Strikingly conspicuous; prominent. See synonyms at noticeable.
3.. Springing; jumping: salient tree toads.
n.
1.. A military position that projects into the position of the enemy.
2.. A projecting angle or part.
[Latin saliens, salient-, present participle of salire, to leap.]

sa'li·ent·ly adv.

I doubt he was referring to jumping tree toads or military positions.

Roger

----- Original Message -----
From: "pvanderwaart" <pvanderwaart@...>
To: <bolger@yahoogroups.com>
Sent: Wednesday, March 10, 2004 6:29 PM
Subject: [bolger] Yuloh's and salient keels [was]


> > And where is that writing found?
>
> "Brad added the inch and a half to her draft while lofting her...
> (He) argued that dropping the rabbet a little would make her easier
> to plank... He correctly added the same amount to the depth of the
> keel to retain the designed amount of sailent, flat-sided keel."
>
> 30-Odd Boats, pp 225
>
>
> Peter
>
>
>
>
> Bolger rules!!!
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[Non-text portions of this message have been removed]
> And where is that writing found?

"Brad added the inch and a half to her draft while lofting her...
(He) argued that dropping the rabbet a little would make her easier
to plank... He correctly added the same amount to the depth of the
keel to retain the designed amount of sailent, flat-sided keel."

30-Odd Boats, pp 225


Peter
I thought the connotation of "Salient Keel" referred to to any part
of the hull that added lateral resistance but was not really a keel.
Like an immersed chine on a sharpie, all of the hull
of a asymetrical cat, like a Hobie 14.
The denotation may be way different.

Justin
--- pvanderwaart wrote:
> In the discussion of the Story "Africa" design,
> perhaps among other places.

And where is that writing found?

Which Bolger boats have salient keels?
Micro, Old Shoe, Sea Bird '86, Swallow
[and others I don't recall.]

In the write up for Swallow, Bolger goes
on about how suitable the large fin is for
propelling a boat with a yuloh oar. The
oar needs the lateral resistance or you
get a 'tail wags the dog' effect.

Last week I sent Bolger copies of the
Micro Navigator construction photos
I shared here, and a letter describing
how I wanted to try a yuloh ,which included
my comments on what I had changed in his
design. He was neutral or positive on my
changes, :

Liking the offset bow transom steps,
Neutral on the increased roof hatch size,
Liking the reduced motor well opening size,
Enthusiastic about the use of a Yuloh,
Liking the ceiling mounted cleats,
Neutral about the changes in the windows,
Neutral about the ballast changes.

In his letter he explained how a yuloh
works "the action of a yuloh is on the
same principle as a propeller,
reciprocating instead of rotating".
This explanation makes much more sense
to me over the 'falling leaf' explanation
offered in the old Small Boat Journal
article, reprinted now on the internet.

I posted my yuloh sketches, Bolger's
letter, and my letter which is necessary
because he makes references to it...

http://hallman.org/bolger/micro/yuloh/

...and the photos are here.

http://community.webshots.com/album/121069753OCENAu
> While I vaguely recall reading the
> expression 'salient keel' in something written by PCB
> I cannot recall where. Do you perchance have the reference?

In the discussion of the Story "Africa" design, perhaps among other
places.

The keel of the SeaBird '86 is mostly filled with lead ingots, not a
single casting, as illustrated in the drawing. Offhand, I can't
remember if there are some free-flooding spaces. My feeling is that,
in Bolger's mind, the alternative to the free-flooding volume is to
have it be solid wood. The greater weight of larger-dimensioned wood
would cost more, and the solid keel would have more buoyancy (not
wanted!) than the flooded hollow keel. The drain holes allow the boat
to weigh less on a trailer. The size of the flooding ports is
relatively immaterial.

Peter
--- Derek Waters wrote:
> While I vaguely recall reading the
> expression 'salient keel' in something
> written by PCB I cannot recall where.
> Do you perchance have the reference?

I forget, sorry.

Another boat with this type of fin
keel is the Sea Bird '86, which has
1000 lbs of lead ballast. I can't
tell from the diagram if it is free
flooding, but I bet that it is.

Bolger wrote:
The keel shown
for Sea Bird �86 is like the one Day wanted
in the first place, with a minimum depth
that ensures reliable handling in had
conditions. A short, deep fin would make
her faster close-hauled with a skilled and
alert helmsman; however, the long, shal-
low keel is stronger, calls for less concen-
tration at the helm, is probably faster
reaching and running, and hangs on bet-
ter hove-to.
Hi Bruce

Salient just means "sticking out". In reference to keels it is sometimes
used as a synonym for 'effective' but the great man usually says exactly
what he means; no more, no less. While I vaguely recall reading the
expression 'salient keel' in something written by PCB I cannot recall where.
Do you perchance have the reference?

FWIW, there's a description of PCB's reasoning on the freeflooding fins to
be found in BWAOM, in the chapter on the plywood 12 1/2.

cheers
Derek