About us

SALVAGE:

In-Water INSPECTION:

In-Water CLEANING:

In-Water REPAIRS, MAINTENANCE:

CIVIL WORKS & ENGINEERING:

SEABED & EARTH ANCHORING:


Chance Civil Engineering


Williams Form Engineering Corporation

~ ~ ~ ~ ~ ~ ~ ~

Subsidiaries:

~ ~ ~ ~ ~ ~ ~ ~

Other useful Websites:

Diving

Nautical Institutions

Maritime Information

ABC Diving® Ltd

Port Vila, P.O. Box 3242 VANUATU South Pacific

Complete Diving Services to Vessels & Civil Engineering Industry

We operate in north and south Pacific Islands; more specifically in Samoa, Fiji, New Caledonia, Vanuatu, Salomon, PNG...

Please, contact us for:

HULL PERFORMANCE & PROPELLER EFFICIENCY

A vessel's fuel performance usually begins decreasing after six months from dry-dock and continues to decrease rapidly.

Underwater marine growth, barnacles, and/or sea grass can cost a ship-owner millions of extra dollars in time and fuel costs each year.

To prevent spending additional dollars for fuel, a ship should be cleaned at least twice a year.

 

Rubert Scale

Grade

 Ra Rz

Loss of Power

(%)

A

 1 6 0
B 2 12 0.5
C 4 24 1.9
D 8 48 2.9
E 16 96 5
F 30 180 5.8

Ra : Roughness Average. Rz : Roughness Depth

During the u/w cleaning the propeller can be smoothened by grades C & D of the Rubert scale

Resulting in => 1.9% to 2.9% improvements

It has been experienced that

the most significant
contribution to the reduction in ship performance

is due to
propeller roughness*

 

*Admittedly, in absolute terms propeller roughness is less important than hull roughness, but in terms of energy loss per unit area, propeller roughness is significantly more important.