Eight man rowing shell

An eight-man rowing shell comprises an elongated hull made of a laminate of a fiber composite skin and having a pointed bow and stern and a hull surface tapering smoothly to a maximum beam and draft therebetween, the hull surface having a waterline length of at least 56.0 feet, a hull entry angle between about 3.8 and 4.3 degrees, a hull exit angle between about 5.0 and 5.5 degrees, a maximum draft below the waterline of between about 0.595 and 0.610 feet, inclusive, and a maximum beam of between about 1.82 and 1.85 feet, inclusive, when the shell is normally loaded.

BACKGROUND OF THE INVENTION 
This invention is directed to boat hull configurations and, in particular, 
hull configurations of rowing shells. 
The performance of boat hulls depends on a number of factors, among them 
wave resistance, form resistance and frictional resistance. For boats 
which are propelled by rowing, other factors come into play, for example, 
oscillation in pitch and surge before, during and after the stroke of the 
oars through the water. For rowing shells or sculls in particular, the 
extreme slenderness of the hulls (in which the length to beam ratios can 
be up to 30 or more) pose special problems with regard to the 
aforementioned factors and to stability in roll. Other performance factors 
include the rigidity of the shell, the depth of the water in which the 
hull is to be used, and the expected race speed. Hull configuration can 
play a decisive role in dealing with one or more of these factors. 
Hulls for rowing shells have advanced considerably in the past years, 
although significant differences still exist even between various models 
of hulls made for the same purpose. However, despite improved 
configurations and the use of advanced composite materials, there still 
exists a need for further hull improvement. Configurations which provide 
an advantage in one area often detract in other areas, with the result of 
little or no overall improvement. Given the relatively long distances of 
the courses over which races are run, for example, two kilometers or more, 
an improvement in hull configuration which results in an overall decrease 
in resistance of one to two percent can result in an improvement of one to 
two boat lengths or more over the length of the course, without any 
increase in effort on the part of the oarsmen. 
Given the needs in rowing competition and deficiencies in the prior art, it 
is therefore an object of this invention to provide an improved boat hull 
configuration for rowing shells. 
It is another object of the present invention to provide an improved boat 
hull configuration which results in lower overall resistance in rowing 
shells. 
It is a further object of the present invention to provide an improved boat 
hull configuration which may be utilized with existing materials and 
building techniques. 
It is yet another object of the present invention to provide an improved 
rowing shell hull configuration which is especially suitable for eight man 
rowing shells. 
SUMMARY OF THE INVENTION 
These and other objects, which will be readily apparent to those skilled in 
the art, are achieved in the present invention which provides a rowing 
shell comprising an elongated hull having a sharp, pointed, canoe-type bow 
and stern and a smoothly tapered hull surface therebetween, the hull 
surface having a waterline length of at least about 53.00 feet. The hull 
surface may have the following cross-section areas, in square feet, below 
the waterline at stations spaced along the hull waterline when the shell 
is normally loaded: 
______________________________________ 
station 0 0.000 .+-. 10% 
station 0.5 0.086 .+-. 10% 
station 1 0.224 .+-. 10% 
station 2 0.492 .+-. 10% 
station 3 0.683 .+-. 10% 
station 4 0.816 .+-. 10% 
station 5 0.868 .+-. 10% 
station 6 0.823 .+-. 10% 
station 7 0.692 .+-. 10% 
station 8 0.492 .+-. 10% 
station 9 0.227 .+-. 10% 
station 9.5 0.079 .+-. 10% 
station 10 0.000 .+-. 10% 
______________________________________ 
wherein station 0 signifies the fore-most point of the hull, and station 10 
signifies the aft-most point of the hull, along the waterline, and wherein 
a unit station spacing is one-tenth of the waterline length. 
The hull waterline length is preferably greater than 56.25 feet, more 
preferably between about 56.5 and 59.0 feet, inclusive, while the hull 
entry and exit angles may be between about 3.8.degree. and 4.3.degree., 
and 5.0.degree. and 5.5.degree., respectively. Other preferable parameters 
such as maximum beam, maximum draft, metacentric height and others are 
discussed further below. 
The hull itself may be made of a laminate of a fiber composite skin over a 
core, such as a carbon fiber/honeycomb laminate.

DETAILED DESCRIPTION OF THE INVENTION 
Reference is made herein to the accompanying FIGS. 1 through 6b which 
depict the boat hull configuration of the present invention in its 
preferred embodiment in an eight man rowing shell. Like numerals are used 
to identify like features throughout the drawings. 
A top plan view of an eight man racing shell 12 incorporating the hull 
configuration of the present invention is depicted in FIG. 1. The shell is 
constructed with a one-piece rigid hull 14 but is shown divided into 
linked bow, mid and stern portions 16, 18 and 20, respectively, for ease 
of drawing and description. Elongated hull 14 forms the basic under 
structure of shell 12 and extends in a smoothly tapered convex hull 
surface from the sharp, pointed canoe-type bow 22 to the maximum beam and 
draft in midsection 18 and back to the sharp, pointed, canoe-type stern 
24. Mounted atop the hull are eight linearly slidable rear facing seats 32 
for the oarsmen. Each seat 32 has a corresponding adjacent footwell 35 and 
an adjustable rowing rigger 30 for the oar, the riggers 30 extending 
outward alternately on the starboard and port sides of the shell. A 
forward facing coxswain's seat 33 is provided near the stern of the shell. 
As shown in further detail in the axial cross section of FIG. 3, hull 14 
comprises a laminate of inner and outer carbon fiber skins, 42, 44, 
respectively, applied on either side of a honeycomb core made of a 
synthetic plastic honeycomb material such as that sold by E. I. DuPont de 
Nemours Co. under the trademark "Nomex". The carbon fiber skin/honeycomb 
core laminate in the hull configuration depicted provides a lightweight 
rigid structure running the entire length of the shell. Seat deck 40, 
supported by deck supports 39 and bulkheads 48 (spaced periodically along 
the length of the interior of the hull) provide additional rigidity to the 
hull whereby traditional bracing, such as a keel, becomes unnecessary. The 
seat decks 40 and bulkheads 48 may be made of honeycomb type laminates 
such as the Nomex.TM. laminate as well. 
Optionally, the hull and other structural components may be made of other 
laminates comprising any combination of carbon fiber, Kevlar.TM. fiber 
(aromatic polyamide fiber available from DuPont), fiberglass, or any other 
fiber composites used in hull skin construction, with or without a core 
made of foam, or an alloy, synthetic or cellulose honeycomb, or any other 
material typically used as a core in composite hull construction. A carbon 
fiber or other type keel may also be employed. 
The adjustable rowing riggers 30 are attached by conventional hardware 
fittings 31 through the hull 14 to interior mounted shoulders 38. These 
shoulders 38, as well as the deck support 39, may be made of any suitable 
material such as white ash wood or any of the aforementioned laminates. 
The rowing riggers 30 are adjustable to the particular dimensions and 
requirements of the oar and oarsmen. Each seat 32 rides on wheels 34, 
attached to the seat undercarriage, which follow linear track sections 36 
mounted on the top of seat deck 40. Hull 14 meets waterline 26 at opposite 
points 54 and 56. 
A side view of the hull of the present invention is depicted in FIG. 2, 
without the seats, riggers or other accessories depicted in FIGS. 1 and 3. 
The hull 14 is again shown as linked bow, mid and stern portions 16, 18, 
and 20, respectively. Waterline 26 is shown in a phantom line superimposed 
along the side of hull 14. The length of the waterline of hull 14 is 
sectioned in equally spaced segments denoted as stations 0 through 10 
wherein station 0 is at the beginning or fore-most point 50 of the hull 
waterline near bow 22 and station 10 is at the end or aft-most point 52 of 
the hull waterline near stern 24. The unit spacing for the segments is 
equal to one-tenth of the length of the waterline of the hull 14, i.e., 
the distance between stations 0 (50) and 10 (52) on the hull. In 
determining the location of waterline 26 with respect to hull 14, normal, 
industry-accepted displacement or loading of the shell is assumed. For the 
eight man shell 12 depicted in the drawings, this loading or displacement 
is approximately 1920 lbs. The section marked "LCB" (28) on the hull is 
the center of buoyancy of the shell and is located approximately 2.05 
inches astern of section 5 (midway along the length of the waterline of 
the hull) to achieve proper trim. 
To describe the hull configuration, graphical representations of the hull 
exterior surface axial cross-sections are shown in FIGS. 4 and 5. FIG. 4 
shows the fore sections of the hull in scale from section 0 through 
station 5, and FIG. 5 shows the aft sections of the hull in scale from 
station 5 through station 10. Each individual hull section is labeled 
along the top horizontal line of the graphs in FIGS. 4 and 5 above one end 
of the corresponding section line. Sections labeled in fractional amounts 
correspond to stations between whole (unit) numbers. The centerline of the 
hull is indicated by the central vertical line labeled "CL" and the space 
between each vertical line to the right and left corresponds to a 
horizontal distance of 1.5 inches on the actual size hull 14. The 
horizontal line labeled "WL" corresponds to the loaded waterline (26) of 
the hull, and the space between each horizontal line above and below 
corresponds to a vertical distance of 3.0 inches on the actual size hull 
14. 
FIGS. 6a and 6b show the entry and exit angles respectively of the hull 
configuration of the present invention. In FIG. 6a, the waterline 26 is 
shown superimposed on a plan view of hull 14 at stations 0, 1/2, and 1 
near bow 22. The straight lines between the fore-most point 50 at station 
0 along the hull waterline and the two points along the hull waterline at 
station 1/2 form the angle 2 .sigma. (sigma) in which .sigma. is termed 
the entry angle of the hull. In FIG. 6b, the waterline 26 is shown 
superimposed on a plan view of hull 14 at stations 9, 91/2 and 10 near 
stern 24. The straight lines between the aft-most point 52 at station 10 
along the hull water line and the two points along the hull waterline at 
station 91/2 form the angle 2 .beta. (beta) in which .beta. is termed the 
exit angle of the hull 14. The entry and exit angles, .sigma. and .beta., 
respectively, are determined as follows: 
EQU .sigma.=arctan[(1/2 hull width @ sta 1/2)/(LWL/20)] 
EQU .beta.arctan[(1/2 hull width @ sta 91/2)/(LWL/20)] 
The extremely fine entry and exit angles of hull 14 contribute to the 
decreased overall resistance of the hull. In general, it is preferred that 
the entry angle sigma be between about 3.8 and 4.3 degrees, inclusive, and 
the exit angle beta be between about 5.0 and 5.5 degrees, inclusive. 
In Table 1 there is set forth the characteristics of the hull of the 
present invention identified as "Vespoli D", as compared to prior art 
hulls identified as "Sims", "Donoratico", "Janousek", "Vespoli A", and 
"Vespoli B". The term "LWL" refers to the length of the waterline, i.e., 
the distance along the waterline between points 50 and 52 as seen in FIG. 
2; the term "BWL" refers to the maximum beam at the waterline, i.e., the 
maximum width or breadth of the hull along the waterline; and the term 
"Thull" refers to the draft of the hull below the waterline, i.e., the 
distance between the waterline and the lowermost point on hull 14. The 
entry and exit angles correspond to the angles sigma and beta as shown in 
FIGS. 6a and 6b, respectively, and are identified by the terms "ENTRY" and 
"EXIT". The displacement of the hull is given by the term "VOL" and the 
wetted surface area of the hull, below the waterline, is given by the term 
" WS". 
The term "GMt" in Table 1 refers to the distance of the transverse 
metacenter above the waterplane of the hull with the center of gravity 
assumed to be at the waterplane (waterline) height. 
TABLE 1 
__________________________________________________________________________ 
COMISON OF ROWING SHELL CHARACTERISTICS 
Model Sims. 
Donor. 
Jano. 
Vesp. A 
Vesp. B 
Vesp. D 
SECTION AREAS (ft.sup.2) 
__________________________________________________________________________ 
Station 
0 0.000 
0.000 
0.000 
0.000 
0.000 0.000 
0.5 0.050 
0.050 
0.145 
0.117 
0.091 0.086 
1 0.160 
0.160 
0.329 
0.272 
0.245 0.224 
2 0.480 
0.480 
0.543 
0.495 
0.523 0.492 
3 0.712 
0.745 
0.685 
0.687 
0.712 0.683 
4 0.840 
0.878 
0.784 
0.824 
0.844 0.816 
5 0.883 0.820 
0.870 
0.893 0.868 
6 0.830 0.793 
0.825 
0.843 0.823 
7 0.678 
0.692 
0.718 
0.696 
0.705 0.692 
8 0.446 
0.469 
0.577 
0.490 
0.501 0.492 
9 0.173 
0.202 
0.317 
0.213 
0.234 0.227 
9.5 0.059 
0.087 
0.150 
0.078 
0.083 0.079 
10 0.000 
0.000 
0.000 
0.000 
0.000 0.000 
LWL (ft.) 
59.33 
56.180 
53.301 
55.855 
54.583 
56.625 
BWL (ft.) 
1.953 
1.805 
1.863 
1.869 
1.873 1.841 
Thull (ft.) 
0.546 
0.687 
0.569 
0.590 
0.614 0.604 
Cp 0.574 
0.574 
0.683 
0.619 
0.617 0.614 
Cm 0.819 
0.736 
0.773 
0.790 
0.776 0.780 
Cwp 0.692 
0.681 
0.716 
0.712 
0.715 0.716 
ENTRY (deg.) 
4.5 4.0 5.15 
4.91 4.40 4.04 
EXIT (deg.) 
3.8 4.0 5.36 
4.71 5.65 5.25 
VOL (ft.sup.3) 
30.70 
30.40 
29.90 
30.10 
30.10 30.20 
WS (ft.sup.2) 
106.10 
99.64 
99.38 
99.80 
98.15 100.13 
GMt (ft) -- -- 0.258 
0.285 
0.273 0.272 
__________________________________________________________________________ 
NOTE: UNIT STATION SING EQUAL TO LWL/10. FOR GMt, CENTER OF GRAVITY IS 
ASSUMED TO BE AT THE WATERPLANE (WATERLINE) HEIGHT. 
The metacenter is the point at the intersection of the centerline and a 
vertical line through the center of buoyancy (as seen in an axial or 
transverse cross-section) when the boat is inclined at small angles of 
heel, up to about 7.degree.-10.degree. from vertical. GMt metacentric 
height is a measure of roll stability, with higher values denoting better 
stability and lower values denoting poorer stability. Preferably, the GMt 
value will be no less than about 0.250 ft., more preferably between about 
0.260 and 0.280 ft., for good roll stability. 
The other parameters given in Table 1 are denoted by the terms "Cp", "Cm", 
and "Cwp" which refer to the prismatic coefficient, the midship section 
coefficient and waterplane coefficient, respectively. These parameters, as 
well as the others given in Table 1, are well known in the hull design and 
naval architecture art, and are defined in such volumes as Principles of 
Naval Architecture, John P. Comstock, Ed., Society of Naval Architects and 
Marine Engineers (1967) the disclosure of which is hereby incorporated by 
reference. 
The dimensions and parameters given in Table 1 for the present invention 
may be varied somewhat to achieve one or more of the advantages of the 
preferred embodiment of hull 14. The length of the waterline of hull 14 
should be greater than 53.0 feet and is preferably at least about 56.00 
feet, more preferably at least about 56.25 feet. Most preferably the 
waterline is between about 56.5 feet and 59.0 feet. The hull section 
areas, below the waterline, may be varied from the amounts given by up to 
plus-or-minus ten (10) percent, preferably no more than plus-or-minus five 
(5) percent. Also, the maximum beam may be between 1.82 and 1.85 feet, the 
draft between 0.595 and 0.610 feet and the wetted surface area of the hull 
between 100.0 and 100.5 square feet. 
The hull configuration described herein has been shown to provide increased 
performance under actual course conditions, without any significant loss 
in roll stability. The advantages of this hull configuration may be seen 
under actual pitching and surging conditions and under a variety of water 
depths, including relatively shallow conditions between about 3 and 10 
meters. The preferred embodiment of the hull configuration of the present 
invention has been found to be up to one to two percent faster than prior 
art configurations, resulting in an advantage of up to one to two shell 
lengths over a typical 2000 meter course without any additional effort in 
rowing. The hull may be easily constructed using conventional techniques 
to achieve its advantages. 
While this invention has been described with reference to specific 
embodiments, it will be recognized by those skilled in the art that 
variations are possible without departing from the spirit and scope of the 
invention, and that it is intended to cover all changes and modifications 
of the invention disclosed herein for the purposes of illustration which 
do not constitute departure from the spirit and scope of the invention.