FOREST AND STREAM. 
run from stein to Stefh, with the minimum orbss-seclion 
as specified for at least one-half; also bilge stringers shall 
run for at least one-half of the extreme length of the boat 
amidships. Clamps and stringers to be of yellow pine or 
its equivalent in strength. 
Sails. 
The sail area shall bcj not more than that specified, and 
not over 80 per cent, of the area shall be in the mainsail. 
The measurer shall be provided with the correct sail plan 
of any boat to be mea-sured, and previous to measurement 
the owner shall cause distinguishing marks, satisfactory 
to the measurer, to be placed on the spars as follows : On 
the mast at the tack at the foot of mainsail ; on the boom 
at the clew of the mainsail ; on the gaff at the peak of the 
u'.ainsail. No part of the inain.sail shall extend beyond 
these mark.?. The marks .shall be black bands painted 
around the spars in a ma'nnei satisfactory to the meas- 
urer ; the inner edges of the bands shall be the limits of the 
.sail. The area of the jib shall he considered to be 80 per 
cent, of the area ol' the forward triangle, viz.: The prod- 
uct of one-half the distance from the point of attachment 
of the tack to the stem or bowsprit to the forward side of 
the inast, multiplied by the distance from the deck at fore 
side of the mast to the intersection of the mast and jib- 
stajf. The extreme distance from mast to end of spin- 
aker boom when in position as used shall not be more 
than the quotient arising from the division of a constant 
by distance frotn deck to throat of spinaker halyard block, 
figured in feet and decimals. The constants shall be: for 
the 25ft. class, 673 ; for the 21ft. class, 400. 
EqiiipmcnI. 
To include anchor and cable as specified, bticket, pump, 
compass, fog horn, boat hook, lead and line, lantern and 
live presenters. 
The total number of persons on board shall not exceed 
that .specified. The helmsman shall be an amateur, and 
not more than one paid hand shall be carried. 
All boats launched previous to the adoption of these 
rules that have been accepted by the Knockabout Associa- 
tion under previous rules .slmll be <vdmitted £q tli?^ qlasses. 
TAHI.K OK RESTBICTIONS. 
C]a.sses. 
Length 0)1 L W-L , maximum '21fi. 'iSft. 
B:am at L W L., minimum Vft. S>fl;. (iiii. 
Freeboard, niiniimim -"in. ?1in. 
Length of cabin flour^ minimum ... • ^'L. "ift. 
Partition at after end of cabin, rainimuin s^\n. J^(in. 
Headroom, minimum J ft "in. ^ft. 
Bsllast, minimum .«,5UliIbs. (i,Ul)l'lbs. 
Reduction of ballast for each inch increase of beam. 651b.s. !»51b.s. 
Area of frames, minimum lin._ i-^in. 
Area oi decV beams, minimum ■ 
Area of house beams, minimum Ji'"- 2jn, 
Spacingof frame, deck and house beams, minimum, fin. ISin, 
Th'ckness of planking, deck and sides of house, min. J^'"- 
Thickness of top of house, minimum f^in. 
Cross section of deck c' amps, minimum iin. 5in. 
Cross section of bilge stringers, minimum , . . , , , . , Jin. Bin. 
Sail area, maximum ....%..-..,.>.■■....*?>. ..60lt.sq.ft, l.OOOsq.ft. 
Draft, ma.\iirunL 5ft. 6ft. 
Crew, msorimum , 3 i 
M^'cight of anchor, minimum 251bs. 40lbs. 
Length of cable, minimum JlWft. 130;&:. - 
Size of cable, minimum 1 K'"- Ij^in. 
Construction — Cruising Division. 
■I'.MSI.I! OF !^t•A.^,TJJI^IGS.. 
Ca:tilfi, Open. 
^ft. lailft. Ii5fi. 7^ ft. If ft. 
Classes. Tn. In. In. In. In. 
A— Stem, sided at head *. »^ 3 1% 
B-Sternpost, sided at tuck 4'/, 3J< 3^ 2^ ]K 
C — Keel and keelson, sectional area ...Sll CO BO 10 S 
D — Frames, sectional area: • 
Heels m 2% 
Bilge i 8 V/^ 1 
Heads 2 ^% 
Maximum spacing , 11 10 !) 8 
E — Floors, V. ood. sectional area !) 7 5 
Equivalent steel L li'xix'^" 9x-^x% Six-2,x}4' 
Maximum spacing it It 20 
F— .'ihelf nr clamp, sectional area: 
Middle 8 (i 4^3 2 1% 
En s 4 3 \yn \ 
G— Bilge stringer, sectional area: 
Middle II 4^ 3 1^2 ••• 
Ends 4 3 9 1 
H — Deck beani, sectional area: 
Main ^Vz 2 ]J< 
Auxiliary and half-beams. , 4% bjjf 9^ 
Maximum spacing. . . , , , ,-..12 11 10 ■■ 
I -Planking, to finish full IJ4 1 Yt ¥« % 
Hood ends above wateriine. 1 % % M 
J -Deck, to finish full* „rj„.,. 1-^ 1_ K 'A 
K - Keel bolts, spaced I2in 1 Yi K 54 • • • 
L— Metal centerplate, maximum thickness. 3/^ Yi ^« '■^ Y?- 
* If dect is canvas covered a reduction of J^in. allowed. 
General Specifications and Explanation of Table. 
Those partions in italics are compulsory; the others are 
only suggested. 
The sizes in the accompanying table are based upon the 
assumption that the construction, as a whole, is planned 
by a 'Competent naval architect, with the usual comple- 
ment of minor mentbers not specifically called for in the 
table; that the yacht is built under cover; and that the 
materials and workinanship are what is commonly called 
"first-class" — namelj^ all wood sound, well seasoned, and 
free from loose knots, shakes and sap, all knees and 
crooks being cut with the grain; all metal work properly 
wrought and neatly finished ; all parts carefully fitted, with 
adjoining surfaces in actual contact throughout the full 
area; and all fastenings carefully selected with regard to 
their relative strength, and the sizes and material of the 
parts they are intended to unite, and that they are properly 
located and driven. 
A — Stem. — The minimum siding (thickness) measured 
at the rabbet at highest point on stemhead, no decrease of 
siding allowed. . . 
Apron. — In some cases an apron is necessary mside of 
" stem, with breasthook, and in the larger classes with 
knightheads. 
B — Sternpost. — Minimum siding at truck (the crossing 
of the rabbet). The siding may diminish from tuck to 
heel. The ruddej-' stock, if of wood, to be equal in diam- 
eter to the siding of post. 
C — Keel. — ^With the usual iron or lead keel and good 
floor construction, there is no necessity for a great depth 
of main (wood) keel to secure vertical strength. The 
minimum of sectional area (breadth multiplied^ by depth 
in the middle of keel) may be made up, if desired, by a 
deeper keel, or may include the keelson, or bedpieces of 
centerboard trunk. 
JENNY WREN, KNOCKABOUT. 
Keel son. — In keel yachts of moderate depth a keelson 
is not absolutely necessary, and the required strength may 
sometimes be obtained to better advantage by the floor 
construction alone. A keelson may be worked to advan- 
tage over the throats of the floors in some cases, the cen- 
terline bolts of metal keel passing through it. In center- 
board yachts, especially in the absence of a deep metal 
outside keel, side keelsons should be worked over the 
heels of floors, or the bedpieces of the trunk should be of 
ample scantling and worked well fore and aft of the slot, 
to serve as keelsons. No absolute sizes of keelson are laid 
down. 
D — ^Frames. — The many different methods of framing 
now in use, and the possibility of new methods in the 
future, make it impossible to prescribe exact dimensions 
or spacing. Both sizes and spacing necessarily differ with 
the various methods of all sawn frames, in futtocks and 
tops, doubled; of single sawn frames from knees, in 
single lengths; of all bent frames of uniform size; and 
of combinations of sawm and bent frames. 
The sises laid down in the table show the minimum 
sectional area of frames ( the siding multiplied by the 
moulding) at three points — the heel of frame where it 
is boxed into the keel, the middle of the frame about the 
Hat of the floor and turn of bilge, and the head at plank- 
sheer. The sectional area is that of a single frame for a 
uniform spacing of ift. in each class. This required area 
may be made up of smaller frames spaced closer together, 
or larger frames further apart; or of combinations of large 
and small frames with appropriate s pacings. This mini- 
mum sectional area shall apply to a space of at least two- 
thirds of the L.W.L. length in the center of the vessel; 
forivard and aft of this, the sectional area may be reduced 
20 per cent. Two adjoining frames abreast each mast and 
one at each runnerplate should be increased in size in pro- 
portion as they are cut by the chainplate fastenings. 
Where bent frames are used in combination with 
sawn, the bent frames may be of uniform scantling from 
end to end ; but the saivn frames must be large enough to 
make up the required average sectional area at the heels 
tvhere they are cut by the fastenings of Hoars. 
Where all bent frames are used, of uniform size from 
heel to head, this size shall be no less than assigned in the 
table for the bilge. 
Spacing of Frames. — The ma.vimuin spacing of frames, 
as given in the fable, is based not on the sise of frames, 
this being variable, but on the thickness of planking al- 
lowed for the class; being the greatest spacing that will 
insure a tight seam with the usual caulking for the mini- 
mum thickness of planking allowed. 
E — Floors.— -The many varieties of floor construction 
make it difficult to establish any standard ; but there should 
be at least six strong Hoors in the center of the vessel in 
tvay of the metal keel, and tivo at each mast step. The 
table gives the minimum sectional area over centerline 
of keel, of wood floor knees, and the equivalent sizes of 
steel angles, with approximate spacing. The size of floors 
may be reduced in proportion if the spacing be reduced. 
In place of wood floors, metal straps or angles of equiva- 
lent strength may be used. The arms of the main floor 
should run up to a length at least equal to the spacing 
given in the table, to alloAV space for fastening through 
heels of frames. In yachts of S section with all bent 
frames, the arms of floors should run up at least to the 
height of the waterline. Provided that the main floors 
are of ample strength, the floors on the smaller frames in 
the middle of the vessel and on all frames in the ends may 
be of flat iron or straight-grained plank. All floors should 
he thoroughly bolted to the keel, stem and horn timbers. 
It is not essential that the main keel bolts should pass 
through the floors, as the large size of the holes weakens 
the knees unnecessarily. The keel bolts may set up on top 
of the wood keel, in which case the floors should be very 
thoroughly fastened by smaller bolts to the wood keel ; or 
. a keelson may be worked over the throats of the floors, 
and the keel bolts may set up on it. 
jr Shelf or Clamp. — The minimum sectional area given 
for the middle shall cover a length of at least one-half of 
the shelf (or clamp) and in the middle, a taper being al- 
lowed to the size given at each end. The ends of deck 
beams may be jogged into top of shelf a distance not ex- 
ceeding one-third of their own .depth. If a beam clamp 
is used, fitted close up to the ptanksheer, the beams being 
thus jogged in for their full depth, the sectional area shall 
he increased in proportion. 
G — Bilge Stringer. — The minimum sectional area at mid- 
dle shall cover at least one-half tJie full length of bilge 
stringer, with taper alloived at the ends. At least one 
bilge stringer must be run on each side, at about the lower 
part of turn of bilge, and two are recommended in any 
case, the sectional area of each being at least one-half of 
that of the single stringer. In yachts whose extreme beain 
exceeds twice the greatest depth from under side of deck 
to upper side of keel, tAvo such stringers on each side 
should always be fitted. 
H — Deck Beams. — The minimum sectional area of deck 
beams shall cover at least the middle third of the beam, al- 
lowing a taper, in the moulding, to each end. There must 
be one main beam at the bitts, two at each mast (partner 
beams), one at fore end of cabin trunk, one at after end, 
two at each skylight, hatch and companion in Hush-decked 
vessels, and one at transom. The auxiliary beams may 
be of the smaller area given. The beams may be spaced at 
will, provided the maximum distance between centers does 
not exceed that given in the table, which is based upon the 
thickness of deck planking. The beams should' be jogged 
into the shelf or clamp a distance equal to one-third of the 
moulded depth of beam at ends. 
1— Planking. — The dimensions given in the table are 
the minimum thicknesses allowed, after final planing, over 
a distance in the middle of the vessel equal to at least one- 
half of the over all length. It is not compulsory that the- 
garboards be of greater thickness than the rest of the 
planking, but this is sometimes desirable, especially in 
the larger yachts. 
The rabbet from the waterline upward on the stem, and 
along the horn timbers, may be cut to the depths given 
in the table, the hood ends of the planks being slightly 
tapered to this reduced depth. 
It is recommended that wherever practicable the plank- 
ing shall be in single lengths, without butt; and that where 
butts are unavoidable they should be made, not on the 
frames, but on butt-blocks between the frames. Butts in 
adjoining strakes should be at least 6ft. apart, and butts 
in the same space should be separated by at least three 
intervening strakes. The planking should be worked in 
narrow widths, especially iir the topsides. 
J — Decking. — The thickness given for the deck plank 
applies also to the planksheer (covering board) and the 
partner planks. The ends of the deck plank should be 
li'ell supported, and in no case should they be ivrought 
to a shim edge, ivhich tvill crush down in caulking. 
K — Keel Bolts. — The sizes given are the minimum di- 
ameters for the main (center line) keel bolts when spaced 
I2in. apart. The sizes and spacing may be varied as long 
as the equivalent strength is maintained. These sizes are 
sufficient for the average metal keel, of about 50 per cent, 
of the total displacement ; but if the keel be deep and nar- 
row it is recommended that the side bolts, of smaller size, 
driven diagonally from each side in alternation, be u.sed 
in addition in the spaces between the main bolts. Where 
considerably less than 50 per cent, of the total displace- 
ment is carried in the metal keel, all holts may be reduced 
in proportion. For yachts to be used only in fresh water, 
steel bolts may be used, without galvanising, both with 
lead and iron keels. 
It is recommended that the outside metal keel, whether 
of lead or iron, be cast before the wood keel is worked 
out; the contraction of the iron or lead is more or less an 
unknown quantity, and the keel, when finally cast, may 
not be of the exact dimensions intended, and may not fit 
the wood keel as worked from the plans. 
Lr— Metal Centerplates. — Solid plate centerplates not 
exceeding the thickness given in the table shall be allowed. 
In built up metal plates and wooden hoards zueighted isjith 
metal, the total weight shall not exceed that of a solid steel 
plate of the same superficial area and of the thickness 
allowed by the table. 
General Details. — It is recommended that diagonal ■ 
straps of steel be worked across the deck frame in way 
of masts and runners, being scored into the beams: 
and that similar straps be worked across the main 
frames, two at the main chainplates on each side and one 
at the runner plate. The deck frame should be specially 
strengthened about the bitts and masts, and ample pro- 
