[bolger] Re: [boatdesign] question on LWL
my Micro hit 8 knots once - that was measured by "knot stick" a contraption
that looks like a test tube has has spring and plunger inside attached to
small elastic that you throw overboard and has a disk on the end. We were
really bookin it. Trees on shore were bending. We were 3 in the boat under
full sail, white caps everywhere, on a reach. I don't know how accurate the
knot stick is. I figure hull speed is about 4 knots as measured by that
thing.
george full
-----Original Message-----
From: Jeff Gilbert <jgilbert@...>
To:boatdesign@onelist.com<boatdesign@onelist.com>; bolger group
<bolger@egroups.com>; Bolgerlist <cnoto@...>
Date: Saturday, September 18, 1999 10:31 AM
Subject: Re: [boatdesign] question on LWL
that looks like a test tube has has spring and plunger inside attached to
small elastic that you throw overboard and has a disk on the end. We were
really bookin it. Trees on shore were bending. We were 3 in the boat under
full sail, white caps everywhere, on a reach. I don't know how accurate the
knot stick is. I figure hull speed is about 4 knots as measured by that
thing.
george full
-----Original Message-----
From: Jeff Gilbert <jgilbert@...>
To:boatdesign@onelist.com<boatdesign@onelist.com>; bolger group
<bolger@egroups.com>; Bolgerlist <cnoto@...>
Date: Saturday, September 18, 1999 10:31 AM
Subject: Re: [boatdesign] question on LWL
>Pippo,25
> its going to depend on the load. In "Boats with an Open Mind" Bolger,
>talking of a Micro undertaking a long cruise 2-up, says that "while the
>boat is nominally all of 4.67m long, each end is a free-flooding well, more
>of cutwater & stern platform than boat proper; the actual watertight
>envelope is barely 3m long." There is a fair old range there, but this
>comes down to surprisingly little when you apply the formula I've often
>seen, viz Hull Speed in Knots (Max) for a very efficient displacement boat
>(Lets give Bolger that!) = 1.33 X sq rt (WLL imperial). (Wharrams go to 2.2
>X)
>This gives 4.2-5.2 knots, which obviously is a far narrower range than
>3-4.67 meters.
> Your best bet for performance is probably to use the conventional tandem
>of SA/D (sail area/displacement) for power available (good cruiser=15;
>gets powerful & quick) & Disp:WLL for ability to haul ass(Cruisers 300,these
>150 gets light & quick.). These are not straight ratios - formulae are in
>every Yachting World boat test. If you can achieve a good trade-off of
>two, you could get good speed out of a tea chest with a mast. The beauty ofachieve
>it I think is it solves your dillemma...because in both formulae the gains
>of the extra waterline are nullified by the extra weight required to
>this increase. All you need is to know what weight of micro gives what
>waterline!!
> Alternately ring some one who has one, & ask em how fast they go!!. (If
>its for sale , divide by 1.5)
>Cheers
>Jeff Gilbert
>Down Under in the land of Vegemite & sunburn.
>
>----- Dear all,
>I'm facing some ambiguity in defining Phil Bolger's Micro's LWL. Most
>sources report a value of 12'2" (3.71 m), while Hullform 6S finds a
>value of 14' (4.3 m). This is clearly due to the fact that the Micro
>keel cuts the water before the canoe body. Now, which one is the correct
>value to use for speed computation and other strange stuff? I'm limiting
>myself now to the dead upright position (0 degrees of heel). Thanks, and
>best regards
>
>Pippo
>
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>
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>------------------------------------------------------------------------
>
Pippo,
its going to depend on the load. In "Boats with an Open Mind" Bolger,
talking of a Micro undertaking a long cruise 2-up, says that "while the
boat is nominally all of 4.67m long, each end is a free-flooding well, more
of cutwater & stern platform than boat proper; the actual watertight
envelope is barely 3m long." There is a fair old range there, but this
comes down to surprisingly little when you apply the formula I've often
seen, viz Hull Speed in Knots (Max) for a very efficient displacement boat
(Lets give Bolger that!) = 1.33 X sq rt (WLL imperial). (Wharrams go to 2.2
X)
This gives 4.2-5.2 knots, which obviously is a far narrower range than
3-4.67 meters.
Your best bet for performance is probably to use the conventional tandem
of SA/D (sail area/displacement) for power available (good cruiser=15; 25
gets powerful & quick) & Disp:WLL for ability to haul ass(Cruisers 300,
150 gets light & quick.). These are not straight ratios - formulae are in
every Yachting World boat test. If you can achieve a good trade-off of these
two, you could get good speed out of a tea chest with a mast. The beauty of
it I think is it solves your dillemma...because in both formulae the gains
of the extra waterline are nullified by the extra weight required to achieve
this increase. All you need is to know what weight of micro gives what
waterline!!
Alternately ring some one who has one, & ask em how fast they go!!. (If
its for sale , divide by 1.5)
Cheers
Jeff Gilbert
Down Under in the land of Vegemite & sunburn.
----- Dear all,
I'm facing some ambiguity in defining Phil Bolger's Micro's LWL. Most
sources report a value of 12'2" (3.71 m), while Hullform 6S finds a
value of 14' (4.3 m). This is clearly due to the fact that the Micro
keel cuts the water before the canoe body. Now, which one is the correct
value to use for speed computation and other strange stuff? I'm limiting
myself now to the dead upright position (0 degrees of heel). Thanks, and
best regards
Pippo
--------------------------- ONElist Sponsor ----------------------------
Share your special moments with family and friends- send PHOTO Greetings
at Zing.com! Use your own photos or choose from a variety of funny,
cute, cool and animated cards.
<a href="http://clickme.onelist.com/ad/zing7">Click Here</a>
------------------------------------------------------------------------
its going to depend on the load. In "Boats with an Open Mind" Bolger,
talking of a Micro undertaking a long cruise 2-up, says that "while the
boat is nominally all of 4.67m long, each end is a free-flooding well, more
of cutwater & stern platform than boat proper; the actual watertight
envelope is barely 3m long." There is a fair old range there, but this
comes down to surprisingly little when you apply the formula I've often
seen, viz Hull Speed in Knots (Max) for a very efficient displacement boat
(Lets give Bolger that!) = 1.33 X sq rt (WLL imperial). (Wharrams go to 2.2
X)
This gives 4.2-5.2 knots, which obviously is a far narrower range than
3-4.67 meters.
Your best bet for performance is probably to use the conventional tandem
of SA/D (sail area/displacement) for power available (good cruiser=15; 25
gets powerful & quick) & Disp:WLL for ability to haul ass(Cruisers 300,
150 gets light & quick.). These are not straight ratios - formulae are in
every Yachting World boat test. If you can achieve a good trade-off of these
two, you could get good speed out of a tea chest with a mast. The beauty of
it I think is it solves your dillemma...because in both formulae the gains
of the extra waterline are nullified by the extra weight required to achieve
this increase. All you need is to know what weight of micro gives what
waterline!!
Alternately ring some one who has one, & ask em how fast they go!!. (If
its for sale , divide by 1.5)
Cheers
Jeff Gilbert
Down Under in the land of Vegemite & sunburn.
----- Dear all,
I'm facing some ambiguity in defining Phil Bolger's Micro's LWL. Most
sources report a value of 12'2" (3.71 m), while Hullform 6S finds a
value of 14' (4.3 m). This is clearly due to the fact that the Micro
keel cuts the water before the canoe body. Now, which one is the correct
value to use for speed computation and other strange stuff? I'm limiting
myself now to the dead upright position (0 degrees of heel). Thanks, and
best regards
Pippo
--------------------------- ONElist Sponsor ----------------------------
Share your special moments with family and friends- send PHOTO Greetings
at Zing.com! Use your own photos or choose from a variety of funny,
cute, cool and animated cards.
<a href="http://clickme.onelist.com/ad/zing7">Click Here</a>
------------------------------------------------------------------------