the characteristic parameters in fender calculation:
– Docking velocity of ship (v)
– Docking angle of ship (?)
– Ship cargo weight (w1)
– Hydrodynamic mass calculated by using ship draft and length (w2)
– Ship type (passenger, tanker, dry-bulk, etc.)
– Docking type
– Fender height or the minimum sheep-dock distance.
Docking energy by using these parameters (ton x m) calculated as
E = (1 / 2g) x (W1 + W2) x V2 x CE x Cs x Cc. Here:
W2 is the displacement load or hydrodynamic mass. It is calculated in sea water mass as the length equals to ship length and the diameter equals to ship draft. The unit is in ton.
Ce is eccentricity coefficient and it equals to 0,22 – 0,25 for tankers and bulk carriers ; 020 – 0,21 for passenger ships, container ships, and RoRo ships; 0,19 – 0,23 for dry-bulk ships; 0,15 – 0,20 for ferries.
Cs is the softness coefficient and it accepts that a small part of ship docking energy absorbed by the ship wave. The value is between 0,9 – 1,0. 0.9 should be taken into consideration for fender sided boats and 1,0 is appropriate for others.
Cc is landing / dock coefficient. It shows the pillowing effect of the water pressed in between the docking ship and dock / landing. For docks, the values between 0,8 – 1,0 are accepted. But for legged docks it is recommended to use the value of 1,0.
V is the docking velocity of the ship (m/sn) and the most important parameter in fender calculation. Since it is used as the square in energy calculation, small changes create big docking energy.
The ship velocity is given below according to ship weight and docking conditions determined by Brolsma in 1977 and involved in BS 6349 standard.
Ship energy docking from stern is calculated as:
E = (1 / 2g) x w1 x v2.
v = 0,15 m/sn
w1 = Net ship weight (loaded)
E = ton x m
The information and calculations are for the information of related people. The exact calculations for fender selection should be made by dock project responsible and the design of the choice should be made by the fender manufacturer.
FENDER DESIGN AND PROJECTS ON DEMAND
Modular fender projection and manufacturing, appropriate for any tonnage, landing or dock type, docking and sea conditions, is possible.
For this, the applicant fills the application form in the following page completely and sends the full information or information on hand. The study has been conducted (if needed) in the place and a project is offered involving technical features, geometry, quantity and price of fender.
Moreover, customer determined (technical features and geometry) fender manufacturing is also possible.