• 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.

2018 March 22

11:14 Bunker prices are flat at the Far East ports of Russia (graph)
10:53 The Maritime Standard announces a special discount for the 2018 Awards
10:27 Brent Crude futures price up 0.01% to $69.48, Light Sweet Crude – up 0.09% to $65.23
10:05 Ukraine’s water transport carried 1,000 passengers in 2M’18, down 64.7%, Y-o-Y
09:41 Cargo transportation by Ukraine’s water transport grew by 41.2% to 0.3 million tonnes in 2M’18
09:19 Baltic Dry Index down to 1,117 points

2018 March 21

18:29 Wight Shipyard wins second order for fast ferry duo from Mexican ferry operator
18:16 Dorian LPG announces third Japanese financing
18:14 GasLog Partners LP announces acquisition of GasLog Gibraltar for $207 million and repayment of intercompany loan
18:04 ABP South Wales achieves new ISO 9001:2016 standard for bulk handling operations
17:42 Port of Gdansk to breathe new life into Dworzec Drzewny Quay
17:20 ABB wins contract to equip two next-generation shuttle tankers with future-proof solutions
17:13 Finnlines decides to exercise the options to lengthen two more ro-ro vessels
17:03 Throughput of Chinese ports up 4.7% to 1.45 billion tonnes in 2M’18
16:39 Pavel Bezmaternykh elected as Director of Eastern-Siberian Inland Navigation Company
16:18 Port of Gdansk overhauls its quays
16:00 Novikombank provides a $100 million loan to STLC
15:47 Huntington Ingalls names two vice presidents
15:21 Gulf Island Fabrication secures contracts for two specialized vessels
15:04 Seatrade Maritime Middle East 2018 to be held in Dubai on 29-31 October as part of UAE Maritime Week
14:42 LUKOIL’s profit in 2017 more than doubled YoY to RUB 418.8 bln
14:23 Wärtsilä and Crowley extend maintenance agreement for 11 articulated tug barges
13:56 IMO launches a video outlining how GMN initiative is uniting MTCCs into a global network
13:29 Ulstein built SOV Acta Auriga completes sea trials
13:11 Dubai will host MARACAD Maritime Innovation Awards on 3 October 2018
13:02 MARACAD 2018 will be held in Dubai on 2-3 October
12:30 17 icebreaker escort operations performed in eastern part of Gulf of Finland during 24 hours on March 20-21
12:09 Port of Quebec to cooperate with Port of Zeebrugge
11:47 Port of Immingham and partners hosted Driving Safety Forward forum
11:39 Vostochny Port JSC exported 5 million tonnes of coal YTD (photo)
10:50 Claimants and defendants in the case on allision of Delta Pioneer tanker with a pier at Primorsk port come to amicable agreement
10:31 Finnlines plans to lengthen two more Ro-Ro ships
10:15 Brent Crude futures price up 0.24% to $67.58, Light Sweet Crude – up 0.25% to $63.7
09:51 ABP's Port of Ayr took delivery of Liebherr crane
09:44 Bunker prices are going up at the Port of Saint-Petersburg, Russia (graph)
09:17 Baltic Dry Index down to 1,122 points
08:08 Scottish ports secure AEO status for Leith, Rosyth and Grangemouth
00:32 Ontario Government accepts Damen proposal for full ferry electrification

2018 March 20

18:20 Sirius Petroleum announces delivery of compact well head systems for Ororo-4 and Ororo-5
18:02 Leningrad Region Governor visits Vyborg Shipyard
17:56 PSA’s Bharat Mumbai Container Terminals enhances Nhava Sheva connectivity with first barge and train volumes
17:40 Van Oord posts results for 2017
17:25 Nevsky Shipyard designed a unique test stand
16:58 Multi-Link Terminals Ltd Oy orders Konecranes ship-to-shore crane for its Helsinki terminal
16:40 SMM 2018: green shipping makes headway
16:01 Transit shipments of containers on Russian Railways' network increased by 40% in January-February 2018
15:36 Rotterdam, the Netherlands will host 21st Ballast Water Management Conference on 7-8 November, 2018
15:13 NWSA container volumes grow 6 percent in February 2018
14:50 IMO Secretary-General Kitack Lim spoke at International Shipping Summit in Istanbul
14:24 More than half of spaces at icebreaker Arktika being built by Baltiysky Zavod are ready for outfitting (photo)
14:12 Maersk Line increases FAK rates from Far East to North Europe
13:35 Dredging works to be performed at seaport of Vladivostok
13:13 BP charters Safe Caledonia for West of Shetland
12:47 Traffic of passenger cars and buses through Crimea Bridge to be launched in May 2018 – RF Transport Ministry (photo)
12:01 Wan Hai Lines to launch new China to Vietnam service
11:51 40 icebreaker escort operations performed in eastern part of Gulf of Finland during 24 hours on March 19-20
11:28 Bunker prices level up at the Far East ports of Russia following last week’s fall (graph)
11:19 Maersk Line stops Winter Fee from world to St Petersburg FCT, RU, St Petersburg, RU, St Petersburg FP, RU, Ust Luga, RU and Kronshtadt
11:03 Skangas celebrates milestone with 1,000 LNG bunkering operations in 2017
10:40 Experts say Wärtsilä – Transas transaction is a step towards Wartsila localization in Russia