233
Locking Cylinders
Harken locking cylinders feature adjustable mechanical locks threaded onto the rod to block rod 
movement and securely fix its position independently of the boat’s pressure system. They are 
commonly used by large cruisers on extended passages to safely lock the rod during pressure 
release and as a safety backup for the hydraulic system. A long-stroke cylinder is often used dur-
ing the mast stepping process to lean the mast forward and hook up the furlers. After commis-
sioning, the cylinder’s mechanical lock is engaged, limiting the stroke for sailing.   
Adjustable lock prevents rod 
movement during pressure release.
For pull forces, see cylinder with corresponding bore and rod diameter on page 232.
*Specify rod and clevis end fittings by adding the appropriate suffix to end of part number. See page 234.
**For pin center length open add stroke length to pin center length closed.     ***Rod ends (clevis) included in weights.     
Part
No.*
- Size
Stroke
Pin center 
length
(closed)**
Weight***
Volume
Diameter
 Gap/pin
Bore
Rod
Max OD
in
mm
in
mm
lb
kg
in³
L
in
mm
in
mm
in
mm
in
mm
 HYCL045160375BCC 
 -17 
 14.8 
 375 
 43.9 
 1116 
 11.9 
 5.42 
 31 
 0.51 
 5/8 
 15.9 
 1 3/4 
 45 
 5/8 
 16 
 2.31 
 59 
 HYCL055190400BCC 
 -22 
 15.7 
 400 
 47.6 
 1210 
 19.2 
 8.71 
 52 
 0.86 
 3/4 
 19.1 
 2 3/16 
 55 
 3/4 
 19 
 2.9 
 73 
 HYCL065220450BCC 
 -30 
 17.7 
 450 
 53.6 
 1362 
 27.2 
 12.36 
 76 
 1.25 
 7/8 
 22.2 
 2 1/2 
 65 
 7/8 
 22 
 3.2 
 81 
 HYCL075250475BCC 
 -40 
 18.7 
 475 
 58.5 
 1487 
 41.6 
 18.86 
 118 
 1.93 
 1 
 25.4 
 3 
 75 
 1 
 25 
 3.8 
 97 
 HYCL080250475BCC 
 -48 
 18.7 
 475 
 59.3 
 1505 
 49.6 
 22.52 
 129 
 2.11 
 1 1/8 
 28.6 
 3 1/8 
 80 
 1 
 25 
 4.1 
 103 
 HYCL090320550BCC 
 -60 
 21.7 
 550 
 67 
 1701 
 70.1 
 31.82 
 182 
 2.98 
 1 1/4 
 31.8 
 3 1/2 
 90 
 1 1/4 
 32 
 4.6 
 116 
 HYCL100320625BCC 
 -90 
 24.6 
 625 
 74.4 
 1889 
 98.9 
 44.85 
 279 
 4.57 
 1 3/8 
 34.9 
 4 
 100 
 1 1/4 
 32 
 5.34 
 136 
Ordering Single-Acting & Locking Cylinders
To order use the chart below. Standard cylinders are black hardcoat-anodized with clevises on both ends. Additional cylinder and rod end 
options of marine eyes, barrel pin eyes, lashing eyes, and blank end fittings are available for a slight upcharge. For optional materials and 
fittings, replace the last three letters of the part number with your selections.
Hardcoat
Clear-anodized
No fitting
Marine 
eye
Lashing 
eye
Clevis
Blank
Clevis
Marine 
eye
Lashing 
eye
Barrel-pin 
eye
Standard Cylinder Part Number
Rod end fittings 
C = Clevis: (standard)
L = Lashing eye
M = Marine eye 
N = No fitting
Cylinder end fittings 
C = Clevis: (standard)
B =  Barrel-pin eye 
L =  Lashing eye  
M = Marine eye 
X = Blank 
Cylinder
Action type
S = Single-acting
L = Locking
Bore diameter (mm)
Rod diameter (mm)
Stroke length (mm)
Materials 
B = Black hardcoat (standard)
C = Clear-anodized aluminum 
H Y C S 0 3 5 1 3 0 3 5 0 B C C
Materials
Rod End Fittings
Cylinder End Fittings

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