The New York herald., 1878-03-10
THE LECTURE SEASON.

monicos, before the members of the Seawanhaka
Yacht Club and their friends The subject Tor the
evening the taking OF sections OF existing vessels
aud delueating them on paper The Professor said,
II vessel could be hauled out dock so that the
load water line would be le,el with the horizon It
would be u very easy thing to measure her; but as
vessels vary in their draught OF water ana have
centreboards and others keels, we need some for
mula shat will bo accurate aud At the same time
flexible enough to suit all cases.
The hrst theory necessary to make o draught is
base line and this Is the first thing we need when we
take oil the sections OF vessel 10 do this we hang
aplummet linc from the stem At the extreme end OF
the load water line, and lower the plummot until it
will range along the keol to the stsrnpost, and low
down on the s,ernpost as possible We now 90 ait
and nail piece OF wood to the sternpost or, IL tho
water line goes beyond the sternpost nail the rud
der; perpendicular TO the sides OF ssrnpost or rud-
der as inc case may be, this piece should bo low
enough TO the base line just between the bot
tom oi keel aud the cardboard streak. Hang plum
met ue from the end OF water line wherever found
allow the line to hang low tho above named
piece, and measure The length OF water line along
the bottom Of keel, from the mark al the alter end
10 the limo at the fore end OF water line rs
near parallel with water line possible The
measurement should be taken with q steel tape
line, as the common tape varies too much for
long measurement. Next sol or on tue keel the
number Of sections intended to be taken oil and
number them, commencing at the stern as No.
and put up peco Of wood ut the foreward plummet
at right angles to tho keel Then stand at the
ward side Of the piecc range the one aft IN vue
then let the assistant 90 10 No aud hold
piece wood into the end against The Keel ana At
right angles to H. raising or lowering until IL ~
actly in ue Win the forward and alter piece. Make
PLAIN mark here the the top touches tho Keel anu
SO 10 tue mex, ono alt and SO ON to the stern.
HINTS FOR PECULIAR CASES.
II the vesseI Is very long Is better 10 go TO the
post wnen tne stations have been marked lar
the middle oflrngth OF keel, as when the day Is
bright IL very hard 10 plainly under the bottom
tho boat TINS is tue base hne Ior the measure
line ~ can be made. Next take a straight piece oi
stuff and lay ~ ayaost the Keel from aection NO l. or
iine may be level Alter marking It IN feet hang
plumb lne IRON The face Of the stern az euch mark
md note The measurement IN mo book. rms will
give the outline Of the stem and figure head. Some
we'll to take OF the ine 0i rabbes also.
Now take straight piece OF stuff hall the width Of
bout aud put II at section NJ. Al the side vi the
keel and perpendicular " IT, and make square with
the keel and level II with spirit level. sometimes
level u piece the forward emu OF the water line,
square 1t and use level all the other base boards
AS keels OF all centreboard vessels taper good
DEAL making u difficult 10 use square 10 regulate .he
boards good way is TO marx OIL on the side Of
the keel eight eet from The edge VI The base bOard
Take of the exact ~dth OF the keel aud add the diner
0f taper to the smaller width ~ the eight ieet
mark. then hold tape Iine from tho added taper
the six feet mark the base board--and when it
centre line oil keel. Now note how aUove or below
the iine the rabbet line AMI hang plumb
from the nrst loot mark on the base board aud set
10 the plank on the bottom. Continue ,ts
until the plumb line just touches The plank
sheer and put the measurements down; then
nolo how far above or below the rabbet tue
top OF the base board IL. Then 20
10 the next section and The sternpost whore
the side .'tumbles in'' from plumb line ut plank
sleor the distance must be noted. Alter measuring
VII the sectops note In the sternpos The vi ns
sreE tnWn nlrhA hAr IN Ahn hn
base line take the measurement from the stern
post at base line TO tatfrail ~ mddle OF same. hen
measure from tnis line 70 alter edge OF the stern
post Ths brings US TO the method 0f hndng the iu-
key to the whole meas urement and must be carefully
done.
GETTING BASS LINZ.
The OF this is, that We want TO got line
the paper TO set oil ali our from, aud the
inclination OF the base line gives 10 us. rne method
OF dong this tOows:Inkc straight pieco Uf stuff
marked pace u al the sido ol The keel from
the end OF the base line forward level correctly
aud mark the upper edge on The Keel With u pencil,
and measure tho distance from the forward sna 10
the post. The longer the piece is tho moro
cirate IL viii be. Note how high above Or below the
base line the pencil marx Is At each Of piece
and take the measurement from where the stern post
GUS the say, ieet forward OF the post
and also to bottom o tho Keel. This measurement
the ~ nypothenuse OF the angle formed by the
post bottom Of the keel, and determines the rake
The length deck. then take of the width a. plank
sueer, at from SIX TO len ioet apart; squarng from
nail In the rail- at middle vi same ut
ihs wood cnds forward, setting of the dis
each side and measuring across. II The rail-
project outside the plank sheer hang n plumblipe
IRON the rail and measure in at The plank sheer Al
you 20 aft In tina plank sheer raIl,
tins will give The li9e OF The ra as well us the plank
sheer.
The Professor, after EXPLAINING how to take the
meas uremeut Of the spars, continued as loilows-
Having settled on the scale Tor The drawing, which
SHOULD be as lurgo AZ possible, we lay down base
line parallel to tho edgo Of the drawing board. put
point where tho stern post Is 10 bo aud down
wa,sr nne. ,nen iay down from this point Inc level
line lad OF on the side ot the Keel anu the
departure from the base line at the end Now set oil
Tho distance, take straight edge, hold II the limo
oil both ut stern post and forward end OF the level
line and continue the line to the end Of the paper.
INCLINATION OF THE BASE LINE.
This gives US the actual inclination oi the base line
to tue horizon, measured all The cross sec
iions with plumb llne-ncre we use the squarc-we
now measure tue length ot water line and sci of tho
distance Of the water line above the base at stern.
Then lay oil the distance OF the sections apart calling
tho stern No l. aud begin 10 lay OIL section No. 2
Put down how far below ABOVE the rabbet from
tho base, ana how far below the rabbet the
ment taken. Put down tho hail wdth oil Keel und
lay down u square line IRON No. 2 ut side OF EeeL
marking oil each place OF measurement Then up
the measurements from TINS hne aud pass curve
through points aud have the shape No. sec.
Proceed aft until all tho sections laid down
the same way. When We como 10 the stern post lay
OIL the rake vi stern post per book
distance that the taral Is ait tho post. Then
lay oil arc, using the distance tho line at
Stern post ~ tafraiL We now 60 forward and lay
head aud rab0et taking care - set II oil from mo
exactly as we We. measured Ill T. We now pass curve
curve lne measurement Is CORRECT We should always
note the shape Of tnc bottom OF tho keel when wo
measure boat, as II Is check IN tho measurement
tor II get the curve we know that mistake
has been made In tho shape Of ,nc keel, Whatever
raise or lower the sections each measurement
must set of tho same distance down or up.
We now square down tue ends OF the water
iiuo a., stern stern pos, ...al ana woodends. and
width OF the deck, starring from tho ends,
compare the width al eacn plank sheer asuremenL
The measurements Of the deck Is not TO be relied on,
Us the wind may dencctod tho plumb line, or II
might not haug freely. Now SET of The lines In
The sheer plan and transfer tho widtns Tor the
body plan, using the load water line a base line.
When we have all tho sections put in we run In
section lines and diagonal limos TO prove our
work.
Professor smith concluded his lecture with an ex-
pianaton Of the manner Of making sail draughtG Tho
me rnbers then repaired TO tue adjoining rooms and
huishod tho evening with social chat the supper
liable.
MUSIC IN MANY LANDs-