SOLAS requirements for steering gears
The SOLAS requirements for steering gears have been established for ships having a traditional propulsion system and one rudder. For ships fitted with alternative propulsion and steering arrangements, such as but not limited to azimuthing propulsors or water jet propulsion systems, SOLAS Regulations II-1/29.1, 29.2.1, 29.3, 29.4, 29.6.1, 29.14, 28.2 and 28.3 are to be interpreted as follows, except 29.14, which is limited to the steering systems having a certain steering capability due to vessel speed also in case propulsion power has failed;
Regulation 29.1
29.1 Unless expressly provided otherwise, every ship shall be provided with a main steering gear and an auxiliary steering gear to the satisfaction of the administration. The main steering gear and the auxiliary steering gear shall be so arranged that the failure of one of them will not render the other one inoperative.
Interpretation
For a ship fitted with multiple steering systems, such as but not limited to azimuthing propulsors or water jet propulsion systems, the requirement in SOLAS II-1/29.1 is considered satisfied if each of the steering systems is equipped with its own steering gear.
Regulation 29.2.1
29.2.1 All the steering gear components and the rudder stock are to be of sound reliable construction to the satisfaction of the Administration. Special consideration shall be given to the suitability of any essential component which is not duplicated. Any such essential component shall, where appropriate, utilize anti-friction bearings such as ball bearings, roller bearings or sleeve bearings which shall be permanently lubricated or provided with lubrication
fittings.
Note:
1)
This UI is to be uniformly implemented by IACS Members and Associates for propulsion and steering systems other than traditional arrangements for a ship’s directional control:
a) when an application for certification of non traditional steering systems is dated on or after 1 January 2012; or
b) which are installed in a new ship for which the date of contract for construction is on or after 1 January 2012.
2)The "contract for construction" date means the date on which the contract to build the vessel is signed between the prospective owner and the shipbuilder. For further details regarding the date of "contract for construction", refer to IACS Procedural requirement (PR) No.29."
Interpretation
29.2.1 All components used in steering arrangements for ship directional control are to be of sound reliable construction to the satisfaction of the classification society. Special consideration shall be given to the suitability of any essential component which is not duplicated. Any such essential component shall, where appropriate, utilize anti-friction bearings such as ball bearings, roller bearings or sleeve bearings which shall be permanently
lubricated or provided with lubrication fittings.
Regulation 29.3
29.3 The main steering gear and rudder stock shall be:
.1 of adequate strength and capable of steering the ship at maximum ahead service speed which shall be demonstrated;
.2 capable of putting the rudder over from 35° on one side to 35° on the other side with the ship at its deepest seagoing draught and running ahead at maximum ahead service speed and under the same conditions, from 35° on either side to 30° on the other side in not more than 28 s.
.3 operated by power where necessary to meet the requirements of paragraph 3.2 and in any case when the Administration requires a rudder stock of over 120 mm diameter in way of the tiller, excluding strengthening for navigation in ice;
.4so designed that they will not be damaged at maximum astern speed; however, this design requirement need not be proved by trials at maximum astern speed and maximum rudder angle.
Interpretation
29.3 The main steering arrangements for ship directional control shall be:
.1of adequate strength and capable of steering the ship at maximum ahead service speed which shall be demonstrated;
.2 capable of changing direction of the ship’s directional control system from one side to the other at declared steering angle limits at an average rotational speed of not less than 2.3°/s with the ship running ahead at maximum ahead service speed;
.3 for all ships, operated by power;
.4 so designed that they will not be damaged at maximum astern speed.
Definition: "declared steering angle limits" are the operational limits in terms of
maximum steering angle, or equivalent, according to manufacturers guidelines for safe
operation, also taking into account the vessels speed or propeller torque/speed or
other limitation; the "declared steering angle limits" are to be declared by the
directional control system manufacturer for each ship specific non-traditional steering
mean; ship's manoeuvrability tests, such as res. MSC.137(76) are to be carried out with
steering angles not exceeding the declared steering angle limits.
Regulation 29.4
29.4 The auxiliary steering shall be:
.1
of adequate strength and capable of steering the ship at navigable speed and of being
brought speedily into action in an emergency;
.2
capable of putting the rudder over from 15° on one side to 15° on the other side in not
more than 60 s with the ship at its deepest sea-going draught and running ahead at one
half of the maximum ahead service speed or 7 knots, whichever is the greater; and
.3
operated by power where necessary to meet the requirements of paragraph 4.2 and in
any case when the Administration requires a rudder stock of over 230 mm diameter in
way of the tiller, excluding strengthening for navigation in ice.
Interpretation
29.4 The auxiliary steering arrangements for ship directional control shall be:
.1
of adequate strength and capable of steering the ship at navigable speed and of being
brought speedily into action in an emergency;
.2
capable of changing direction of the ship’s directional control system from one side to
the other at declared steering angle limits at an average rotational speed, of not less
than 0.5°/s; with the ship running ahead at one half of the maximum ahead service
speed or 7 knots, whichever is the greater; and
.3
for all ships, operated by power where necessary to meet the requirements of 29.4.2
and in any ship having power of more than 2,500 kW propulsion power per thruster unit.
Definition: "declared steering angle limits" are the operational limits in terms of
maximum steering angle, or equivalent, according to manufacturers guidelines for safe
operation, also taking into account the vessels speed or propeller torque/speed or
other limitation; the "declared steering angle limits" are to be declared by the
directional control system manufacturer for each ship specific non-traditional steering
mean; ship's manoeuvrability tests, such as res. MSC.137(76) are to be carried out with
steering angles not exceeding the declared steering angle limits.
Regulation 29.6.1
29.6.1 Where the main steering gear comprises two or more identical power units, an
auxiliary steering gear need not be fitted, provided that:
.1
in a passenger ship, the main steering gear is capable of operating the rudder as
required by paragraph 3.2 while any one of the power units is out of operation;
.2
in a cargo ship, the main steering gear is capable of operating the rudder as required by
paragraph 3.2 while operating with all power units;
.3
the main steering gear is arranged so that after a single failure in its piping system or in
one of the power units the defect can be isolated so that steering capability can be
maintained or speedily regained.
Interpretation
Definition: Steering Gear Power unit - For the purposes of alternative steering
arrangements, the steering gear power unit shall be considered as defined in SOLAS
Reg.II-1/3. For electric steering gears refer SOLAS II-1/3., electric steering motor shall
be considered as part of power unit and actuator.
29.6.1 Where the main steering arrangements for ship directional control comprises two or
more identical power units, auxiliary steering arrangements need not be fitted, provided that:
.1
in a passenger ship, the main steering arrangements are capable of operating the
ship’s directional control system as required by paragraph 3.2 while any one of the
power units is out of operation;
.2
in a cargo ship, the main steering arrangements are capable of operating the ship’s
directional control system as required by paragraph 3.2 while operating with all power
units;
.3
the main steering arrangements are arranged so that after a single failure in its piping or
in one of the power units the defect can be isolated so that steering capability can be
maintained or speedily regained.
In a ship fitted with multiple steering systems, such as but not limited to azimuthing
propulsors or water jet propulsion systems, an auxiliary steering gear need not be fitted,
provided that:
-
in a passenger ship, each of the steering systems is fitted with two or more identical
power units, capable of satisfying the requirements in Reg. 29.3.2 while any one of the
power units is out of operation;
-
in a cargo ship, each of the steering systems is fitted with one or more identical power
units, capable of satisfying the requirements in Reg. 29.3.2 while operating with all
power units;
-
each of the steering systems is arranged so that after a single failure in its piping or in
one of the power units, ship steering capability (but not individual steering system
operation) can be maintained or speedily regained (e.g. by the possibility of positioning
the failed steering system in a neutral position in an emergency, if needed).
Regulation 29.14
29.14 Where the rudder stock is required to be over 230 mm diameter in way of the tiller,
excluding strengthening for navigation in ice, an alternative power supply, sufficient at least to
supply the steering gear power unit which complies with the requirements of paragraph 4.2
and also its associated control system and the rudder angle indicator, shall be provided
automatically, within 45 s, either from the emergency source of electrical power or from an
independent source of power located in the steering gear compartment. This independent
source of power shall be used only for this purpose. In every ship of 10,000 gross tonnage
and upwards, the alternative power supply shall have a capacity for at least 30 min of
continuous operation and in any other ship for at least 10 min.
Interpretation
This interpretation is valid to the steering systems having a certain proven steering capability
29.14 Where the propulsion power exceeds 2,500kW per thruster unit, an alternative power
supply, sufficient at least to supply the steering arrangements which complies with the
requirements of paragraph 4.2 and also its associated control system and the steering
system response indicator, shall be provided automatically, within 45 s, either from the
emergency source of electrical power or from an independent source of power located in the
steering gear compartment. This independent source of power shall be used only for this
purpose. In every ship of 10,000 gross tonnage and upwards, the alternative power supply
shall have a capacity for at least 30 min of continuous operation and in any other ship for at
least 10 min.
Regulation 28 - Means of going astern
Regulation 28.2
28.2 The ability of the machinery to reverse the direction of thrust of the propeller in sufficient
time, and so to bring the ship to rest within a reasonable distance from maximum ahead
service speed, shall be demonstrated and recorded.
Interpretation
28.2 The ability of the machinery to reverse the direction of thrust in sufficient time, and so to
bring the ship to rest within a reasonable distance from maximum ahead service speed, shall
be demonstrated and recorded.
Regulation 28.3
28.3 The stopping times, ship headings and distances recorded on trials, together with the
results of trials to determine the ability of ships having multiple propellers to navigate and
manoeuvre with one or more propellers inoperative, shall be available on board for the use of
the master or designated personnel.
Interpretation
28.3 The stopping times, ship headings and distances recorded on trials, together with the
results of trials to determine the ability of ships having multiple propulsion/steering
arrangements to navigate and manoeuvre with one or more of these devices inoperative,
shall be available on board for the use of the master or designated personnel.