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SHRIMP BEAM TRAWLS
DESIGN, CONSTRUCTION AND OPERATION
by
Bent A. Christensen, Professor
and
John Dorman, Research Assistant
Department of Civil Engineering
University of Florida
TECHNICAL PAPER NO. 6
August 1978
Florida Sea Grant
SHRIMP BEAM TRAWLS
DESIGN, CONSTRUCTION AND OPERATION
by
Bent A. Christensen, Professor
and
John Dorman, Research Assistant
Department of Civil Engineering
University of Florida
TECHNICAL PAPER NO. 6
August 1978
The information contained in this paper was
developed under the auspices of the Florida Sea Grant
College Program, with support from the NOAA Office of
Sea Grant, U. S. Department of Commerce, grant number
04-8-M01-76; and the Coastal Plains Regional Commission
of Charleston, S.C. This document is a Technical Paper
of the State University System of Florida Sea Grant
College Program, 2001 McCarty Hall, University of
Florida, Gainesville, FL 32611. Technical Papers are
duplicated in limited quantities for specialized
audiences requiring rapid access to information which
may be unedited.
SHRIMP BEAM TRAWLS
Design, Construction and Operation
A Preliminary Report
Report No. 7804
Hydraulic Laboratory
Department of Civil Engineering
University of Florida
Gainesville, Floirda 32611
TABLE OF CONTENT
FORWARD . . . . .
1 INTRODUCTION . . . .
2 EARLY DEVELOPMENTS. ALUMINUM BEAM TRAWLS
(1st Generation) . . .
3 STEEL BEAM TRAWLS (2nd Generation) .
4 STEEL BEAM TRAWLS (3rd Generation) .
5 CONCLUSIONS. . . . ..
6 ACKNOWLEDGEMENTS . . .
Photos of Experimental Beam Trawls. Figures 1 -
Construction Plans of 3rd Generation Beam Trawl.
Construction Plans of 1st Generation Beam Trawl.
Construction Plans of 2nd Generation Beam Trawl.
20 . .
Figures 21 26
Figures 27 28
Figure 29 .
Page
i
. 2
S 5
S 6
. 12
S 13
. 14-33
S34-39
. 40-41
S. 42
FOREWORD
This preliminary report is being written and distributed in response
to numerous inquiries concerning the beam trawl recently developed by the
University of Florida's Hydraulic Laboratory. Although testing of the trawl
is not complete at the present time (August, 1978) it is hoped that this
information adequately answers at least some of the questions presented.
Additional information and test results will be provided when they become
available. The following discussion is devoted primarily to those persons
who wish to build and operate this type of trawling system.
The development and testing of this trawl was made possible by a
grant from:
The Coastal Plains Regional Commission
1725 K Street NW
Washington, D.C. 20006
The Hydraulic Laboratory will be grateful for any data generated by
the use of this type of gear. Such information may be mailed to:
Hydraulic Laboratory
Department of Civil Engineering
University of Florida
Gainesville, FL 32611
1. INTRODUCTION
The idea of the beam trawl, namely keeping a trawl or net open by means
of a structural member, i.e. the beam, functioning structurally as a column,
is in no way new. As a matter of fact, a crude version of the beam trawl was
the forerunner of the otter door trawl that is so widely used by the fishing
industry today. The modern otter door trawl was easier to use and manipulate
than the old clumpsy beam trawls. It required less manpower but more fuel
since it applies a hydrodynamic force to keep the net open, a hydrodynamic
force which must be generated by the powerplant on board the trawler.
In the days when fossil fuel was plentiful and cheap the switch to the
otter door trawl seemed logical. However, today with fuel shortages and in-
creasing fuel prices it does not seem rational to use scarce and expensive
fossil fuel to provide the force that keeps the net open when this force may
be provided free of charge so to speak by a beam. In other words the time
has come when reconsidering the beam trawl and redesigning and modernizing
it for improved ease of handling and fishing efficiency may prove an answer
to some of the fishing industry's present economical problems.
The beam trawl discussed in this report is now in its third generation.
Improvements have been made such that each generation was supposedly better
than earlier models, but this does not imply that further improvements are
not possible. Each fisherman should be able to make changes that will fully
adapt its use to his particular situation. The modifications that have been
made, as well as potential modification, will be discussed herein. Photos
are provided of the three generations of beam trawls, and drawings with the
specifications necessary for their construction are included. Unless otherwise
noted, the dimensions given on the drawings are the same as those of the ex-
perimental beam trawls shown in the photos.
2. EARLY DEVELOPMENTS. ALUMINUM BEAM TRAWLS. (1st Generation)
Figures through 6 are photos of the first generation of the beam trawl
developed by this laboratory. The corresponding dimensions are shown in
Figures 27 and 28. The beam with end frames is 3 feet high, 31 feet long
and,except shoes and some hardware, is all heli-arc welded aluminum. This beam
was built earlier in conjunction with tests being made on door trawls and the
development of model laws for trawls. Laboratory and ocean tests revealed
that the webbing itself was only responsible for about half of the towing
force being used and the remaining force was required to pull the doors. At-
tempts to devise a system that would perform the same function as the doors,
but be cheaper fuel-wise to pull, led to the construction and testing of the
beam trawl. Those first tests revealed that the beam was indeed easier to pull,
requiring about 25% less total force than the doors to fish a bottom strip of
the same width as the one fished by a conventional otter door trawl. Since
development of the beam was not the main objective at that time, only little
information was recorded concerning its performance. However, work done
during the past nine months has been directly oriented toward the evaluation
and development of a fuel efficient beam trawl.
The following comments are made in reference to the aluminum beam. The
net used was made especially for the beam and is basically a modified flat
net less wings. It has 2 inch webbing of #15 twine and a foot rope length of
approximately 45 feet. Although the middle of the head rope is shown connected
to the pipe, this is not necessary unless it is desired to limit the fishing
height. Also, the length of the head rope is not critical to the performance
of the beam and may be longer if consistent with the rest of the net. Most
of the-tests done recently have used longer head ropes attached only to the
ends of the pipe. Connecting the head ropeto the pipe at its center makes
*All figures appear at the end of text.
the net slightly easier to pull, but the savings will probably not offset the
loss in area fished. The length of the foot rope is about right. It should be
from 1 1/2 to 2 times the length of the beam. Shorter lengths tend to put too
much bending and compression in the pipe. Longer lengths may cause the net to
wind up, pick up too much trash, or not fish properly.
It should be noted that the net has no leg lines, although leg lines of
1 or 2 feet are suggested. The shoes on the beam slide straight forward along
the bottom and do not kick up as much trash and mud as a set of doors. The
long leg lines normally used to clear trash are therefore not needed. Note
also that the net has a loop chain along the full length of the foot rope as well
as a tickler chain stretched between the two end frames. No information con-
cerning this setup was recorded, but tests made on the second and third gener-
ation beams indicate that the tickler chain helps increase the catch.
As evident from the photos, short bridle cables were used on the aluminum
beam. The beam could be lifted high enough to clear the water when the junc-
tion point of the bridles was pulled to the towing block. One bad effect of
short bridle cables is that they cause large bending and compressive forces in
the pipe. The aluminum pipes were strong enough to withstand these forces
with no ill effects. The second and third generation beams use long bridle
cables and smaller pipes. These beams can also be lifted out of the water by
pinching the cables together as they are pulled through the block. It is ob-
vious that the cables can only be pulled so far for fear of buckling the pipe.
Several different arrangements of long bridle cables have been tested. Some
of them performed very well and others were very poor.
Different holes were provided in the end frames of the aluminum beam for
connection of the outside bridle cables. Although the cables are shown con-
nected to the center holes, the bottom holes should probably have been used.
Connecting the cables too high on the frames causes the beam to rotate forward
and lifts the rear of the frame and shoe. This may or may not be desirable.
If the beam rotates too much, the center cable will go slack and the beam will
rock.
The photos indicate some of the procedure used to load the beam. It ap-
pears that most of the lifting was done by the net. Depending on the equipment
available on the trawler and its arrangement, there are any number of ways to
handle the beam. One particularly good method will be explained when the
second generation beam is discussed. Since trawlers are not set up to handle
beams, putting it on board may be difficult in some cases. The development of
new methods for storing the beam is one area of potential improvement. At-
taching the beam to the outrigger or providing rail mounted storage racks are
good possibilities.
Figures 5 and 6 show more of the details of how the beam is assembled
than any of the other photos. The end frames have a short section of pipe
which slides over the long pipes, and they are secured by putting a bolt in
holes bored through the pipes. The center section of pipe is larger than the
two outside sections. The pipes used for the aluminum beam were selected such
that the outside pipes would telescope into the center section for easier
handling, however, this was not done on any of the newer beams simply because
handling the fully extended beam did not seem to createany problems for the
crews during the actual ocean testing of the trawls.
The pipes for the newer beams were selected for a close fit and not to
telescope. Although some changes were made, the same general relationship
between pieces of the beam was used for all three generations of beam trawl.
They each have three sections of pipe and two end frames. These five pieces
are completely separable.
3. STEEL BEAM TRAWLS (2nd Generation)
The following comments concern the second generation beam trawl shown
in Figures 7 through 16 with dimensions indicated in Figure 29. Two of these
beams were tested in February, 1978, and primary consideration was given to
their performance. Reproduction of this beam is not suggested since it was
designed for test purposes and not for routine fishing. The third generation
beam, to be discussed later, is designed for routine fishing and incorporates
all of the improvements found to be necessary from tests of the second gener-
ation beam. Both the second and third generation beams are 30 feet long and
3 feet high. They are made of steel and not aluminum.
Two different nets were used on the second generation beams. One was
a conventional two seam balloon net; and the other was a new beam net, dif-
ferent from the net used on the aluminum beam. Hanging to hanging, the
balloon net was 50 feet long on the head rope and 60 feet long on the foot
rope. The beam net was 34 feet long on the head rope and 41 feet long on
the foot rope. The leg lines on both head ropes were adjusted to make the
nets pull properly from the beams. Both nets used 2 inch webbing and #15
twine. Fishing side by side for two days, the balloon net caught twice as
many shrimp as the beam net.
During these tests both beams used a 5/16 inch tickler chain stretched
between the two end frames. They were set to pull about 2 feet forward of
the foot rope. Figures 7 through 10 show the second generation beam in its
original form. The pipes used were the smallest size considered adequate.
Figures 9 and 10 show that they were not adequate since both beams bent their
center section of pipe due to unexpected problems. Both of these sections
were replaced with larger pipes, and the beams performed satisfactorily for
the remaining three days of testing. The beams bent partly because of the
bridle cable system that was used and partly because the pipe was too small
to start with. The beam with the short net was bent considerably more than
the other beam, indicating an increase in the forces acting on the pipe
because of the short foot rope. Figures 11 and 12 show the beam after being
repaired.
Figures 13 and 14 show part of the sequence of steps used to load the
beams. Figures 9 and 10 both indicate clearly the two handling lines which
were attached to each beam. Using the line on the end of the beam and
nearest to the boat, one end of the beam was raised as shown in Figure 13.
The block used for this was located above the winch. By easing off on the
towing cable the beam was allowed to move toward the boat. When the beam was
in far enough, the lifting line was let off and the end of the beam was set
on deck as shown in Figure 14. Although it was not done at the time, it is
best to make the end of the beam fast after this step. Using the line at the
one-third point of the beam and farthest from the boat, the other end of the
beam was simultaneously swung and lifted as the towing cable was eased out.
The block used for this was located in the rigging at the stern of the boat.
When the beam had swung parallel to the boat, the lifting line was let off and
the pipe was set on the stern rail and made fast. The end of the beam was
allowed to protrude over the stern. This particular loading procedure is
safe and efficient. It was devised and implemented by Captain Jimmy Moore,
whose trawler pulled the beams.
The last day of testing for the second generation beam was devoted to
direct comparison of the beam with conventional doors. The beam with the 50
foot two seam balloon net was pulled from one side of the trawler, and nine
by forty doors with a 60 foot four seam flat net was pulled from the other
side. Three drags were made. On the first drag the beam caught 2 2/3 pounds
of shrimp for each pound caught by the doors. On the second drag the beam
caught 2 pounds ofshrimp for each pound caught by the doors. The
last drag was started by a sharp 1800 turn at full throttle which unfortu-
nately-was enough to flip the beam upside down as shown in Figure 15. The
beam caught 3/4 pound of shrimp for each pound caught by the doors. 1This is
the extent of direct comparison of the two systems in shallow water. Addi-
tional testing is planned for shallow water to better verify the performance
of the two systems. The results will be released when available.
Figure 16shows a net that has caught itself. The trawler was stopped
quickly from full throttle. The beam also stopped. The bag, however,did not
stop because of inertia of the water moving with it. It came far enough
forward to cross over the head rope. When the trawl was pulled again, the
head rope crossed over the bag. This is not normal for the beam but has been
included here because it did happen. It should also be noted that flipping
the beam is not normal, but it may happen. The beam can be flipped back up-
right with the lazy line. A better method is to drop it back down in the
water and turn the boat through 1800 in a circle with the beam at the center
of the circle.
It took about twice as much total force to pull the doors as it did the
beam. This ratio would change if the beam was compared with smaller doors.
4. STEEL BEAM TRAWLS (3rd Generation)
Figures 17 through 20 show the third generation beam. Its dimensions
are given in Figures 21 through 26. It is very similar to the second gener-
ation beam but has many improvements. It is lighter, stronger, easier to
pull, easier to handle because of the improved bridle cables, and fishes a
larger area.
The steel used to build the end frames of the third beam was not as
thick as that used in the second. Also, the unnecessary parts used only for
testing were omitted and the shoes were shortened. The center section of
pipe is the same size as the replacement pipe used on the second beam, but
the outside pipes are larger. The distance between the pipe and the bottom
of the shoe is also larger. It is not obvious from the pictures, but the
pipes have small steel rods welded to them along their top and bottom about
1 inch forward of the center line of the pipe. These small rods change the
character of the flow of water around the pipes and are expected to reduce
drag thereby making them easier to pull.
The third generation beam was tested out of Key West during May, 1978,
to check its performance in deep water. The beam was pulled from one side
of the trawler and seven by thirty-four doors were pulled from the other.
Four different nets were used with the beam. The doors pulled a 39 foot
flat net with 5 foot leg lines. This net was never changed and was used as
a standard for comparison with the beam and its nets. The depth of water
fished in ranged from 200 to 245 fathoms, but most of the drags were made at
about 230 fathoms (1380 feet). Twenty-four drags of approximately 4 hours
duration each were made in 6 days. The following table gives the description
of the nets used on the beam and the total catch comparisons.
Catch Catch
Beam Doors Ratio
Beam Net 1.27
2 inch mesh, #15 Twine 79/lb 100/lb to
Foot Rope 54 ft pounds 1
Beam Net 1.77
2 inch mesh, #18 Twine 163/lb 288/1b to
Foot Rope 48 ft 1
Two Seam Balloon Net 1.36
2 inch mesh, #15 Twine 234/1b 319/1b to
Foot Rope 60 ft 1
Head Rope 50 ft
39 Foot Flat Net 2.28
2 inch mesh, #15 Twine 159/lb 363/1b to
Same net as on doors 1
In every case the doors did better than the beam in deep water. Both
drums had 700 fathoms of towing cable, giving a cable length-to-depth
ratio of about 3 to 1. This is apparently not sufficient for the beam to
make good bottom contact. Although the beam got to the bottom, it pro-
bably never had both ends touching at the same time. The force measure-
ments made indicated that the beam drag was below normal and in the same
range as measurements made earlier when the beam was pulled without
bottom contact. The doors have one advantage in that the force of the
water also takes them to the bottom. The beam has only its weight to take
it down. This advantage may be reversed for shallow water. Figure 20
shows the shine on the bottom of the shoe which indicates that the beam
was at least touching bottom part of the time. This picture was taken at
the end of the 14th drag on the fourth day of testing. When the picture
was taken, the beam was upside down as shown in Figure 19. The beam is
very stable and has flipped only twice. The first time it flipped was
mentioned earlier. This time the two rigs caught together. The beam came
up upside down, and one of the chains was pulled out of a door.
If the beam was practically flying, as suggested earlier, it should be
reflected in the catch made by each net. The beam net with #15 twine and
the balloon net both have a long foot rope. When pulled without interfer-
ence from the bottom, these nets should expand more in the vertical direc-
tion. If one end of the beam is allowed to touch bottom, then the net that
expanded the most should have more of its net touch bottom. The short flat
net probably had the least vertical expansion. As reflected in the catch
comparison, the beams catchseems proportional to its nets ability to expand
vertically. This effect is also shown from the fact that the catch in-
creased when Texas dropdown was used instead of a tickler stretched between
the end frames. The dropdown helped hold down the bottom of the net. This
tendency of the beam to fly is not normal but is the result of insufficient
towing cable length.
Figures 17 and 25 show the arrangement of the bridle cables for the
third generation beam. Please refer to Figure 25 for the following discus-
sion. The four cables connected to the pipe are arranged such that they all
come tight at the same time. This helps equalize the forces acting on the
pipe. The longer outside bridle cables reduce the bending and compression
of the pipe that would be present if short bridles were used. The beam is
weakest when the two outside bridle cables are pinched together as it is
pulled close to the towing block. It is designed to be pulled to within
8 or 9 feet from the block but not much closer. This bridle system was ar-
ranged such that the forward ends of the two outside cables could be dis-
connected from their normal position and reconnected to the center cable at
about 48 feet from the pipe. By doing this the beam could be suspended by
the center cable which is connected to the four short cables. The junction
point of these four lines may be moved closer to the pipe if necessary;
say to within 7 feet. The length of 60 feet was chosen so that when the
beam was pulled up, the junction point of the longer cables would be at the
winch. If the two outside cables are made fast at this point, the winch
can be let out and these two cables disconnected. When the winch is brought
in again, the center cable will support the beam. This was done several
times during testing and went smoothly. A piece of chain looped around the
winch frame was used to make the outside cables fast. The chain held a
small shackle which the cable thimbles would not slide through. By ar-
ranging the cables so that they can be disconnected, the length of the lines
can be changed by adding a short piece of chain or a shackle. When the beam
is let out again, it can be made to drag heel heavy, toe heavy or whatever
is desired. The position the beam takes while being pulled is defined by
the length of the bridle cables and the angle of the towing cable.
Figure 17 shows that there are several different places to attach the
outside bridle cables to the end frames. The higher the cables are con-
nected, the smaller the forces in the pipe. Since different types of nets
pull differently, it is suggested that the cables be attached as high as
possible and still have the beam function properly. If it is desired to
increase the fishing height, extensions can be welded or bolted to the end
frame to attach the head rope to. The bridle cables may be connected in a
higher position if this is done. Extensions of more than 2 1/2 feet are
not suggested since they would make the beam tend to tip over backwards.
Extensions should be positioned to lean forward.
5. CONCLUSIONS
At the present time, before the final modification of the third gen-
eration beam trawl for more efficient deep water shrimping, the following
conclusions may be drawn:
a. The beam trawl is substantially easier to pull and will under
all circumstances save fuel when compared to a conventional
otter door trawl of same size.
b. The newly designed beam trawls are easy to handle. They do
not create more handling problems to a two man crew than the
otter door trawl.
c. Once in the water the beam trawl seems to be more stable than
the otter door trawl. This is true not only on its way to the
bottom but also after bottom contact has been established.
d. In shallow water the beam trawl has been demonstrated to fish
cleaner and catch substantially more shrimp per unit time
trawling than a conventional otter door trawl of the same
size.
e. In deep water the experimental beam trawl was surpassed in
catch by the otter door trawl. Dynamometer readings show
that this was due to lack of weight that prevented proper
bottom contact. Improvements are possible by increasing the
beam weight without increasing drag.
f. It is reasonable to expect that the beam trawl will be
equally successful for other bottom fish.
6. ACKNOWLEDGEMENTS
The development of the beam trawl has required a great deal of cooper-
ation from many individuals and organizations. Although recognition of
everyone involved is not possible, we at the Hydraulic Laboratory would like
to express our sincere appreciation and gratitude for the many contributions
that have been made and give formal recognition to those individuals whose
dedicated effort and talents have been key elements in this research.
Without the cooperaLion we have received, little of our accomplishments
would have been possible.
Captains David Cook, Jimmy Moore, Gene Lewis, and their crews have
provided the trawlers and manpower necessary for field testing of the three
generations of beam trawl. The many contributions and suggestions made by
these men have been invaluable and have provided guidelines for many im-
provements.
Standard Hardware, Inc. in Fernandina Beach, Florida, and its employees
have provided many courteous services. Our special appreciation is extended
to W. H. "Billy" Burbank, Jr. and his crew in the net shop. They made all
of the nets that have been used on the beams and door trawls.
Mr. William F. Feger, Jr., owner and operator of "Feger Seafood" in
New Smyrna Beach, Florida, has provided a great deal of assistance through-
out the duration of this project. We are grateful to have his continued
support.
We would also like to extend our appreciation to the agents of the
Florida Marine Advisory Program, who have been a valuable link between our
laboratory in Gainesville and the fishermen throughout the state.
Figure 1 1st Generation Beam.
Figure 2 1st Generation Beam.
15
-.
Figure 3 1st Generation Beam.
Figure 4 1st Generation Beam.
17
Figure 5 1st Generation Beam.
.-r~
~hir;..
:I~~rr
:; e
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:;~ ~:
'~' LA~''~
I i. I
Figure 6 1st Generation Beam.
19
Figure 7 Original 2nd Generation Beam. Two Seam Net.
20
Figure 8 Original 2nd Generation.
Beam Net.
, i
Figure 9 Original 2nd Generation Beam. Two Seam Net.
Figure 10 Original 2nd Generation Beam. Beam Net.
I
Figure 11 Modified 2nd Generation Beam. Two Seam Net.
24
Figure 12 Modified 2nd Generation Beam. Beam Net.
25
Figure 13 2nd Generation Beam During Loading.
26
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ryr~
u L-~~_ ---~-
'- `--c---
~1--rrr
E`~-~,f~-~p~
s
4rs~C~1~L~r,
~2~: 5---~ U lr~f~52
Figure 14 2nd Generation Beam During Loading.
27
Figure 15 2nd Generation Beam.
28
~aw-
ZCr -*~
5-. vP~ ~r -
- 1;93~ -Bi- r
ma.U7. ,a b,-
- -r ~ -z..r"-
~I,-- *PI."l. A-
Figure 16 2nd Generation Beam.
Two Seam Balloon Net.
Figure 17 3rd Generation Beam.
30
Figure 18 3rd Generation Beam.
31
Figure 19 3rd Generation Beam.
E~'S~c"~ar~~
~pLcrr75;r+T~-~LP3
Figure 20 3rd Generation Beam Underside of Shoe.
33
THiR GENERATE ION AM
End Frame
Channel
Cross Section
7T-
=LL
American
Standard
Channel C 3 x 4.1
(3in wide- x 4.1 Ib/ft)
Total Le.ngth
o1 ft
(2 stock length of 2o ft)
Fij re-
BEAM (STEEL)
~I HIRD
G ENER AT \ON
k
THI~D ENEAT ONBEAM (5TEEiL')
End Fromere- Outside. View
-H
Pltte on Both
5ide5 ~P Frome.
Angle. 3"x Z"x
/
I
I
!
Insert x 2?- x 3"
H*- 2-2
Pipe
4" Standard /Weight
Length 18"
0. D. -4.500"; D.- 4.02.("
C~1
-I
Figure. 22
I ,
(STEEL~
GENERATION
BEAM
3j"
5ides of Frome
-L ''
4
THIRD
THIRO G~N~RAT~ON BEA~I (S,-~E2
-- *'3 Eye Nut
\\ End Frame
\ I-nside Vie-w
' Nu%
o" -- 7 -
Shoe- "T Fcat Bar 45 Long -
Drilled and tapped for -" bolts on 10" c.nte.rs .
Eye Nuts: /Welded in p\ac.e as shown. Siz.e. optional.
Note: The. s.hacpe. o-f the curve-d portion o the. shoe.
is not c-ri-it.\. It may be a smooth curve or
a series of bends as asNo\n.
Figure- 23
36
j
BEAM
STEELE)
THIRD GENERATION
THIRD GENERATION BEAI (STEEL')
Pipes (for30 ft Beam)
-- 1"--1 lt2'0"
22"- -t12. 12"--
0o 0
I
0 0
F-\o" ,o "-9-
3 dimee.
All koles are. T diomeae.r.
Not to Sc.le
2I 1BI
20
o
So o
H- -1 1o0
Use. x "
30
--- 8'l
8F
e.ye oolt to conne..-c.
8 10o"
SI Larger Pipes
SSmaller Pipes
Note: T)he- 3 pipe- Is
will u.)Ql y not- do so.
of the- 5mc\cle.r pipes5
4" Standard W eight O.D. 4.5-00' I.D.
3 StandQrd Weight O.D. 4.000"; I.D.
supposed to -ft inside tihe- 4" pipe.)
It- ius aljy necersscrj +to tur-
unti\ they fit.
Figure.. 24
4.02>" r
3.5-s" 4
how vever it
doAJrn the ends
T7HRD GENE.RATION BEAM STEEL.)
Bridle Cable. System
iew All Ccb,\e.s ore. '
-F-
(0'
60'
I I
C"T
Top
V ITndicates 5Shckcle.
C MQin Towing Cable
Shacle- t Top Line. to t'llt beam bock.
Shockle to Bottom Line_ to ~ilt be-am orward.
Figure- 25
38
Add
Add
C
Top V
391
i'* c
TIIRD GENERATION BEAM (STEEL)
Pipes (for 25 ft Beamr)
O O
---------" 'o" I
So12
0 0
'ih 6 '"(22
G"7t
Not to 5ccile
2--L"
r 10 ......
0 0
9 .-9
r-89
o o
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257A "
71011
Lctv-9er FPipes5 3- Stctriord Vveqj+ht O.D. 4.00" I.D. 3.548&
5rlle. Pipels 3"5tar'dQv-d We'ht O.D. 3.500"; T.D. 3.068's
U5Pe TVjrd G-rnerv-citton Encl Frcme- with 32j Pipe.
Use. Third Garer-tion Br-idle- Ccb1b. Syrem.
,irre. 26
-~- If"
----
I___pi [ _o~ r-
8 9
A
W"
6
FIRST
GENERATION BEAM
(ALUMrINUM)
JL, i 4xs c4
T YP'c~
c ~14
All pie-ces are .lded
the shvoe, whichh is
together.- e-xe-pt
boltte'a in p\ac-e.
36" ------)
3
---P =- = --- = -=E~E~~
FIRST GENERATION BEAM (ALUMINUM)
PiLps and Bridle CaLles
Not to scale
---------- ^
S4 16'6 4
-- --12" 12"--I --
Io_ o- o I o o _o _
7 -_1--" 81~ 3 ,-
^ ------ c( '3"---- -- --- >---
Top View
All cables Y 4'
Not. to scale
Lorer Pipes 5" Extra Stronr,
Smaller Pipes 4" Stand~ard
OD. 5.5s3"; I.D. 4.813"
O.D. 4.500"; I.D. 4.026"
Figure_
41
GENERATION BEAM MoDIVIED (ST-EEL)
It ~
' I
Shown for compare son only. See third gene.rction beam.
Bridle connector and insert omitted.
All pipes tor modified second g~ner-cion bec~a are.
the .ame as those. or the. ir-d enero ion beam.
r1 8 ~
I
4 x33
L2J
ss corN D
|
RSS
HIDE
