Introduction; Maintenance Overview - Kongsberg Frydenbo IRV-2 Maintenance Manual

Maintenance Manual
1.

Introduction

This manual provides the Kongsberg Maritime maintenance recommendations and instructions for
all Frydenbö IRV-2 type Steering Gears. Pictures and illustrations used in this manual may deviate
from the equipment on board your vessel. All recommendations are provided in relation to general
Class requirements and guidelines.
The KONGSBERG IMO Steering Gear (IRV) fulfils the single failure criteria of IMO for tankers over
100 000 DWT. The IRV Steering Gears comprise two identical power actuating systems separated
with a double hydraulic sealing system within a single housing.
2.

Maintenance Overview

Kongsberg Maritime (KM) Steering Gears are designed for safe operation with a minimum
maintenance need. However, to prevent unexpected problems or downtime, it is recommended
that the users maintain the Steering Gear system at regular intervals.
For scheduled class survey and general service or repair, it is recommended to use Kongsberg
Maritime service engineers. This will decrease the time of repair to a minimum and ensure
continuous safe operation.
This document describes all relevant maintenance procedures and activities to be carried out by the
crew, in addition to the maintenance recommended to be performed by Kongsberg Maritime service
engineers. Any other information may be found in the Steering Gear USER MANUAL or by contacting
service.dmss@km.kongsberg.com.
The IRV Steering Gears are of robust design and by following the recommended maintenance
schedule, long and reliable operation is secured. However, after a certain number of years in
operation, it is necessary to overhaul the equipment and change internal wear parts. The internal
wear parts mainly consist of internal seals, radial bearings (linings) and axial bearings (thrust
bearing). The overhaul interval is dependent on factors such as:
•
Weight of rudder and rudderstock.
•
Alignment of rudderstock and Steering Gear.
•
Radial forces from rudder and the operation profiles of the Steering Gear.
•
Oil temperature and oil condition.
•
Number of operating hours.
•
Other conditions such as DP operations that will generate more wear than steaming.
The condition of most wear parts is possible to detect by visual inspection or testing. However, the
thrust bearing, for example, can normally only be inspected by draining oil from the actuator and
opening the top cover to physically measure the clearance under the rotor. For some of the new
generation actuators there is a measuring device available, as an option, for control of the thrust
bearing without draining oil and removal of the top cover.
Although the internal wear parts are designed to last well in excess of 5 years, it is wise to use the
opportunity during the regular class survey dockings to confirm the Steering Gear internal
condition. If more than half worn, it should be considered if the parts can last until next planned
docking.
Monitoring the condition and performance of the equipment and taking notice of any changes is
important in order to reveal any problems developing before a breakdown occurs.
KONGSBERG PROPRIETARY. This document and its accompanying elements contain KONGSBERG
information which is proprietary and confidential. Any disclosure, copying, distribution or use is prohibited if not
otherwise explicitly agreed with KONGSBERG in writing. Any authorized reproduction, in whole or in part, must
include this legend. ©2022 KONGSBERG - All rights reserved.
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