• 2018 February 16 09:39

    New DNV GL class notations aim to improve stern tube bearing performance

    DNV GL has revised its class rules for single stern tube bearing installations and introduced two new class notations, “Shaft align(1)” and “Shaft align(2)”, to help customers better manage the risk of stern tube bearing failure. The new class notations can be assigned to both newbuilds and vessels in service in conjunction with propeller shaft withdrawal, DNV GL said in its press release.

    The classification rules covering shaft alignment are formulated to achieve an acceptable distribution of loading on the shaft bearings and lubrication of the aft bearing, taking into consideration the bending moment induced by the propeller during operation. However, during turning manoeuvers at higher ship speeds, exaggerated propeller bending moments can occur, potentially resulting in a reduced shaft-bearing contact area and an exponential increase in local pressure and thermal loading. This could cause damage to the aft bearing. Most of the reported bearing damages have been observed in the aft-most part of the aft bearing, typically during a starboard turn on a right-handed propeller installation. The new rules put additional focus on the impact of these transient hydrodynamic propeller forces and moments, induced in turning conditions, on the aft-most propeller shaft bearing.

    In the “Shaft align” class notations and the revised main class requirements for single stern tube bearing installations, a multi-sloped bearing design is mandatory. This is further supplemented by an additional evaluation of the aft bearing lubrication condition considering an increased propeller-induced hydrodynamic bending moment on the aft bearing in the downward direction. Additional design and installation criteria also assist to increase the operating margins and enhance bearing performance and fatigue lifetime in normal continuous running conditions.

    The notation “Shaft align(1)” is intended for propulsion systems installed on vessels with conventional hull forms and incorporates enhanced aft bearing performance during normal and turning operating conditions. “Shaft align(2)” is intended for propulsion systems requiring additional calculations to predict hydrodynamic propeller loads during turning conditions, for example vessels with non-conventional hull forms such as asymmetric stern, twin skeg etc. Design and in-service follow-up rules for the class notations are included in the updated DNV GL rules for the classification of ships, Pt.6 Ch.2 Sec 10 and Pt.7 Ch.1 Sec 6(38) respectively.

    About DNV GL
    DNV GL is a global quality assurance and risk management company.
     


2024 March 19

09:47 IMO to open regional office in Fiji to serve the Pacific

2024 March 18

18:13 Brunvoll propulsion chosen for ESVAGT's growing fleet of SOVs
17:42 ADNOC signs second long-term Heads of Agreement for Ruwais LNG Project
17:37 Cemre Marin Endustri shipyard holds launching ceremony for CMAL's MV Isle of Islay
17:24 Fortescue successfully conducts world’s first use of ammonia as a marine fuel in a dual-fueled ammonia-powered vessel in the Port of Singapore
17:02 APL updates on European Union’s Import Control System 2
16:03 MED Marine contracted to build MED-A2575 series tug for SVS Maritime
15:31 Hanwha Ocean and BV join hands to develop a 270K LNG carrier
15:17 HD Korea Shipbuilding awarded contracts for three VLACs
14:18 Port of Skagen and Stillstrom partner to decarbonise anchorage zone with offshore charging solutions
13:22 Sanmar delivers 6th battery electric power tugboat to Norwegian operator
13:16 COSCO SHIPPING Lines announces the launch of OCEAN Alliance DAY 8 product this year
12:21 Dutch offshore wind farm approved by LR
11:39 ClassNK awards first-ever notation for improvements in living and working environment to Fuyo Kaiun's bulk carrier "ELETTRA"
11:31 Davie strengthens Québec’s shipbuilding industry by supporting the reorientation of AFCDC
10:44 Storylines and Brodosplit shipyard renew ship building contract to construct private residence ship
10:25 BOEM announces environmental review of proposed wind energy project offshore New Jersey
09:51 First ‘flying’ electric ferry to debut in New Zealand in 2025

2024 March 17

16:31 Norwegian Shipowners' Association names Harald Fotland as its President
15:22 ABS Wavesight Nautical Systems now supports fully digital, streamlined SIRE 2.0 inspections
14:15 TechnipFMC selected by NEP to deliver the first all-electric iEPCI for CCS
13:03 US sanctions shipping company, targeting Iran and Houthi rebels
11:01 The first hybrid electric vessel built in South America will use a Corvus battery system
09:47 Kalmar and Forterra sign JDA for autonomous terminal tractor

2024 March 16

16:24 The Netherlands selects Naval Group for its submarine replacement program
15:41 Equinor exercises options to extend four-year drilling contracts
14:17 GONDAN Shipbuilders hosts launching ceremony for Edda Wind's CSOV C503
13:47 Van Oord, Van Aalsburg partner to further develop circular fascine mattresses
12:13 Snam wins "A" raing in CDP's Suppliers Engagement Rating for efforts against climate change
10:54 ULSTEIN unveils new subsea vessel for offshore energy tasks

2024 March 15

18:07 DNV gives nod to Friede & Goldman BargeRack solution
18:02 New partnership enables faster offshore wind installations in the U.S.
17:53 First production line at ‘World’s Largest Monopile Factory’ to go live in July
17:21 Brunvoll DP2 upgrades for more Mokster vessels
16:55 CMA CGM to suspend its calls at Port au Prince, Haiti
16:03 GEFO's LNG DF chemical tanker Tosca gets Green Award
15:19 CEVA Logistics develops new vehicle logistics business at the Port of Dunkirk
14:11 MPA: SaR operation continues for a missing crew member of the Liberia-flagged UTOPIA
13:07 To develop the Far East it makes sense to build a new shipyard in the country’s eastern regions, President Putin said
12:48 World’s first use of ammonia as a marine fuel in a dual-fuelled ammonia-powered vessel in the Port of Singapore
11:39 COSCO Shipping calls Port of Genoa, Italy with 20,000 TEU vessels on regular basis
10:03 DMC contracted to supply rudder systems for the world’s largest PCTCs

2024 March 14

18:04 Shearwater awarded seismic survey for UK carbon capture and storage project
17:15 UAE, world leaders discuss maritime corridor for aid to Gaza
16:05 Marine fuel sales at Singapore drop to a three-month low in February
15:43 World Shipping Council selects NCB for liner shipping Cargo Safety Program
15:00 ZIM reports results for 2023
14:57 DP World announces 2023 results
14:29 HaiSea unveils new operations facility for the world’s greenest tugboat fleet
13:44 DEME awards KENC with engineering and fabrication scope on multiple offshore wind installation projects
13:25 MABUX: Bunker Outlook, Week 11, 2024
12:43 Wartsila Lifecycle Agreement to support optimised low-emission operations for two P&O Ferries vessels
11:35 Hapag-Lloyd transport volumes up by 0.5% to 11.9 million TEU in 2023
10:51 NYK and Astomos Energy christen new dual-fuel LPG carrier
10:25 Port of Long Beach container volume up 24.1% to 674,723 TEUs in Feb 2024

2024 March 13

18:02 Lebanese, French officials float a plan to rebuild Beirut port nearly 4 years after huge explosion
17:23 Ascenz Marorka obtains type approval for cyber-security from Bureau Veritas for its digital solutions
16:58 USDOT announces $500 mln for ports available through the Port Infrastructure Development Program
15:44 RINA wins contract to create global investment plan for cruise sector
15:23 Hede International Shipping enters the Transpacific container trade
14:43 Concordia Damen wins contract to deliver a CDS2410 River Pusher to Transporte Fluviales Frey Bentos
14:13 CMA CGM Group launches its first loyalty program SEA REWARD
13:13 Cargill posts results of the six-month test period of the world’s first wind-powered ocean vessel
12:24 Rotterdam's Gate Terminal sees need for more LNG bunkering capacity at Rotterdam
11:58 MOL announces delivery of LNG-fueled car carrier CERULEAN ACE
11:24 Panama Canal announces increase in daily slots at Panamax locks
10:25 thyssenkrupp Veerhaven plans the climate-friendly pusher tug

2024 March 12

18:04 Cosco Shipping installs Iridium Global Maritime Distress and Safety System on PCTC Cosco Tengfei
17:30 LR issues Project Certificate for CrossWind Hollandse Kust Noord wind farm
17:16 The shipping industry to need €3.7 trillion by 2050 to move towards a zero-pollution era