"SKIFF" OPERATING & INSTRUCTION MANUAL

• Document Type: FOIA
• Collection: FOIA Collection
• Document Number (FOIA) /ESDN (CREST): 0005578301
• Release Decision: RIPPUB
• Original Classification: U
• Document Page Count: 49
• Document Creation Date: June 24, 2015
• Document Release Date: November 2, 2011
• Case Number: F-2010-01480
• Publication Date: December 1, 1954

ZIRAT 74 & ?NSTRUCTION
CGCUE4ENT NO.
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NEXT R3? c'ti i;ASE:
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DATE:-~~~-k~7 SEF7 i8 t~
APPROVED FOR RELEASE[] DATE:
27-Oct-2011
 Purpose .............................s...........1....? 3"
....e.
General Description ............................. 4
Equipment Furnished ................................... 5
Capabilities and Performance Specifications........... 6
Limitations ........................................... 7
Detailed Description .................................. 8.
Water Ballast System .................................. 9-10
Compressed Air System.... ............................. 11
Fuel System ................... .......................9 12
Operating Procedures ................................... 1319
A. Procedure Before Starting Engine after Over
night Layupo....................w..........0. 13?11
B. Procedure When Running Buoyant.............., 14
Co Procedure When Running Semi-Submerged........ 3.4-15
D, Procedure When Changing From Semi-Submerged to
Buoyant, Underwayo ........................... 15016
E. Procedure in Securing Skiff at End of Day.... 16-17
F, Procedure in Caching Skiff ................... 17-18
G. Retrieving Procedure ..................ee.... 18-19
H. Towing Procedure ........................... .a 19
Maintenance Procedures.... ....... Go ..........20?23
A. Daily Check-Off List During Operating Periods 20
B. Semi-Monthly Check-Off List, or after 25 Hours
Engine Operation, whichever is Sooner........ 20?21
C. Monthly Check-Off List, ............. I ...... 1. 21
D, BiaMontth7,y Check-Off List .................... 22
E, Semi-Annual Check-Off List ................... 22
F. Preparing for Below-Freezing Weather..,.,.... 22
G, Check-Off List Prior to Going on a Mission... 2223
H. Pre-Testing Engine Compartment with
Compressed Air 23
 Hints on Trouble-Shooting . . e.e a e.e 0 0 0 0 . . . 24?28
Engine. o' o' a' a' o' a o o . o' o o' o 0 0 o . . o o . 2.445
Water Ballast Pump . e o b' 0 0 E. o. o o 25
Ballast Trim System . . . a o 0 . . 0 . . 025
High Pressure Air System . . . . . . 26
Raytheon Fume Detector 0 . . d'.'. 0 .'. . .'.. 26
Fathometer o 0 0 0 0 0 0. 0 0 0 6 0 0 0 0 0 27
Engine Compartment 0 ? . . . o o o . . 0 e o 0 27
Fuel System ; 0 0 . . . . . . ? 0 0 . . . . . . 27=28
Steering Mechanism ? e o o. o o a o o a o. 0 0 28
Propeller Shaft . . ? ? o e . . . e . . ? e . 0 28
Ballast and Loading Instructions . .
. . . .
3031
Spare Parts and Equipment List . . . . . .
. . . .
j2-33
List of Blueprints of Design Plans . . . . . .
. . . .
34
Procedure in Laying up Skiff.. . . . . ... . .
. . . .
35
Quarterly Checks While Laid Up . . . . ; ? o 0
a . . .
36
Recommissioning After a Layup . . . . . . . .
. .
36
Figure 1 = General Views of Skiff
Figure 2 = Flooding and Venting System
Figure 3 Cut=away View of Crew Compartment Flooding
and Pumping System
Figure 4 = Compressed Air System
Figure 5 - Speed and Fuel Consumption Curves
Six Photographs of Skiff are Appended
Operation and Maintenance Manual for Universal Atomic Four
(Two copies with each Skiff)
c1o o;
Blueprints of Design Plans of Skiff (Two sets with each
Skiff - 15 prints per set. See page 34.)
 a. It can be sunk without personnel in depths up to
30 feet and left on the bottom for periods up to
three to four weeks. It can subsequently be re-
trieved by a swimmer on a free dive or by a diver,
by using the self-contained compressed air ballast
blowing system which is part of the craft. The
vessel can immediately thereafter be placed in
operation.
be It can operate with three men and cargo in either
a semi-submerged condition or a frilly buoyant
condition with all water ballast tanks blown. It
may also operate in any desired intermediate con-
dition of water ballasting, The purpose of operat-
ing semi-submerged is to minimize the possibility
of radar and visual detection.
c. Operating ranges:
Trim
R.P.M.
Speed
Range
Buoyant
2000
5 Knots
150 Nautical Miles
Semi-submerged
2000
4 Knots
110 Nautical Miles
 The craft is arranged as shown in Fig. 1. The crew com-
partment is amidships with bolted access hatch on the after
bulkhead, giving access to a watertight casing containing the
engine and battery and with gasoline tank at after end. The
hull is divided into three watertight compartments identified
as forward trim compartment, main ballast compartment and after
trim compartment. The main ballast compartment is further
divided by a partial center line bulkhead intended to reduce
effects of free surface water. A ballast pump, belt-driven
from the shaft, is located in the after end of the main com-
partment. On each side of the engine compartment is an air
flask for blowing ballast. A third air flask for purging
explosive gases from the engine compartment is fitted in a well
at after end of main ballast compartment. Access to the crew
compartment is through a quick acting hatch operable from above
or below. A plexiglass dome to provide vision for the operator
is located in the after end. A watertight aluminum hatch is.
fitted over the engine compartment. In addition, deck plates,
removable for inspection and maintenance purposes, are provided
throughout the length of the boat. The craft is fitted with
four lifting eyes and is provided with a lifting sling.
A 34" and a 47" snorkel are provided. The 47" is not
needed unless unusually heavy seas, over six feet high, are
expected to be encountered.
The Skiff can be shipped in a wooden crate, the lower part
of which is in the form of a cradle. The crate can be cut dawn,
leaving a hauling cradle, on which are mounted wheels. This
cradle is useful for hauling the Skiff out of the water, on a
ramp, and for resting the Skiff when docked for painting, storage,
etc.
 1 = Wilfred C. White, Echo Depth Sounder, fathometer,
0-80 feet, portable.
'l--d-Raytheon-gashwise-dete c tor--tnstntled-.
1 - Bendix Pioneer aircraft, Type 1823?5, compass, radium
dial and electric light for 6 volts.
1 - Inclinometer (aircraft "turn and bank") installed.
1 - Air blower, electric, portable.
I - Radio antennae and lead-in (installed), suitable for
use with FRC-6 or PRC-10 radios or equivalent.
1 - Towing penidant.
1 - Wire propeller lock.
 Length overall (Hull) 19'c.0-1/2"
Depth to too of Gas Vent 6'=91/2"
Beam (over Guards) 5'-3"
Draft, buoyant (With Full Gas & Normal 608# Load) 2'=8"
Draft, semi-submerged (With full Gas & Normal 608# Load) 30-8"
Max. submergence depth
30'=0?
Engine: Universal "Atomic Four"
2-9/16" x 3