A modern cruise ferry is a complex package of engineering, comprising of safety systems, structural design, installed power, command and control systems, each of which are significant engineering projects in their own right, writes Derek Byrne
Mech

A modern cruise ferry is a complex package of engineering, comprising of safety systems, structural design, installed power, command and control systems, each of which are significant engineering projects in their own right, writes Derek Byrne.

So how is a reliable new ship engineered, designed and delivered to provide the same level of performance that the MV Ulysses has delivered since her introduction in 2001?

MD Andrew Sheen on the bridge.

Irish Ferries’ new luxury cruise ferry made its maiden voyage from Dublin to Holyhead on January 22, 2019. This was the first tangible output of a €144 million investment to customers aboard.

Andrew Sheen, managing director of Irish Ferries, described the project. A career marine engineer, he is a former chief engineer and ship surveyor. He rejoined Irish Ferries from the UK’s Maritime and Coastguard Agency in 2010 initially as operations director, becoming managing director in 2015.

Irish Ferries has benefited from a business and engineering leader who not only directs the company but effectively headed up the new vessel project, too.

The process commenced by looking back at service experience with the current fleet. A common theme was evident, the MV Ulysses built by Aker Finnyards, its design based on a combination of a common shipyard design platform and some bespoke design elements from Irish Ferries; so too was the MV Isle of Inishmore built by Van der Giessen in the Netherlands.

Enviable reliability in service


Both ships provided enviable reliability in service and served as a reference standard for the new ship; significant input also came from front-line staff at all levels which helped to guide the specification.

Market research was undertaken to determine which shipyards had the required engineering, hydrodynamic capability and capacity to deliver a quality product in time for the summer service in 2018.

A programme of visits was undertaken across the world and a German shipyard, Flensburger Schiffbau-Gesellschaft (FSG), emerged as a very strong contender.

Irish Ferries’ own market analysis indicated there would be significant demand for ferries and that the development of its new ship would give a shipyard a strong product platform for future orders.

The project was financed through a combination of self funding and a €75 million loan facility from the European Investment Bank.

Irish Ferries kept the contract payment profile simple, a downpayment of 20 per cent was made at contract signing and the balance of 80 per cent was paid on acceptance of the completed vessel at the shipyard.

A warranty period of one year was agreed, which suits Irish Ferries given its own in-house technical competence, and associated risk is low given FSG’s track record of delivering proven reliable ships.

Operational performance of the new ship is based upon elements of the routes she serves as well as experience with the existing fleet.

Stern access, port side.

The short sea Dublin/Holyhead route features double ramp loading at ports which can enable a two-hour and 45-minute turnaround time, whereas the longer Dublin/Cherbourg route may only access a single loading/unloading ramp and turnaround times are four hours.

Internally, the proven design of the MV Ulysses vehicle decks is replicated with a total of four vehicle decks comprising of a double-deck drive-through with the other two decks reached by internal ramps.

Sea conditions are very different on both routes, so in order to optimise the hull design for both, Irish Ferries provided the shipyard with three years of wind and wave weather data for the routes to be operated.

Dublin Port challenging to design around


Dublin Port was challenging to design around, with only two metres clearance of water under the MV Ulysses in worst case conditions, this constrains propeller sizing and drives up propeller shaft operational speed as a consequence.

Propeller design must be carefully optimised to mitigate the risk of cavitation which can cause impingement corrosion on the blades while they must also be optimised to transfer power and minimise fuel consumption.

An extensive programme of testing was undertaken using the large hydrodynamic and cavitation tunnel (HYKAT) in Hamburg, and in collaboration with propulsion system supplier Caterpillar, to understand the interaction of the propellers with the hull form and the wake field arising.

Control console.

Vortex shedding was minimised by fitting propeller base caps, thus streamlining the flow of water over propeller and rudder installations giving an efficiency improvement of between two and five per cent.

Ships are costly to procure and even more so to operate, for example the MV Ulysses may burn up to 70 tonnes of fuel oil in 24 hours of operation between Dublin and Holyhead.

Irish Ferries began the project by undertaking a ‘needs analysis’ and developed its own in-house operational cost models of the ship to estimate life-cycle costs and to validate cost models submitted at tender stage.

The model focused on speed, capacity, turnaround times and multiple route operations, for example, operations on the Dublin/Holyhead route dictate a service speed of 20 knots and Dublin/Cherbourg 22.5 knots respectively.

Irish Ferries developed an outline technical specification in-house which grew initially from 100 pages to more than 1,000 pages by tender stage.

Some specialist help was provided by OSK Ship Tech in Denmark which advised Irish Ferries on ship stability and also provided interior architecture design to the shipyard for the public areas.

Vessel load management, real time calculation of vessel shear force and bending moment.

A key tactic was to keep the technical specification flexible in order to generate as much international market interest as possible.

In tandem, Irish Ferries undertook visits to prospective international shipyards in order to understand technical and production capability.

It also undertook a due diligence exercise to understand the product platforms on offer, and performance in service on other ships already delivered.

Hull classification ‘Ice Class 1A’


Although it is not intended that the vessel will operate in icy waters while in service, Irish Ferries specified the hull classification as ‘Ice Class 1A’ to protect the residual value of the ship and to access a greater charter market if required in the future.

The engineering impact of this decision is that the hull is considerably strengthened, rudder stocks are a greater size to cope with ice flow and propulsion shafts are bigger than an equivalent ship without this ‘ice classification’.

Sheen was keen to point out that the company also paid considerable detail to smaller installations which may affect overall reliability.

For example, variable frequency drive motors were specified for HVAC systems, such as sea water pumps. The first cost of equipment acquisition is higher, however, operational costs are lower and reliability is inherently better since motor speeds can be varied and matched to actual load requirements.

There is also the added benefit that the on-board power generation and distribution equipment sees less sudden power demands.

Prospective shipyards were selected based upon a number of elements including, design capability, hydrodynamic expertise, engineering capability and lead times to delivery.

Irish Ferries put together an equipment ‘makers list’ of major equipment based upon service experience with its existing vessels and technological advancement since the MV Ulysses entered service in 2001.

Reaction time in event of unplanned maintenance event


The ‘makers list’ took into account the capability of the equipment manufacturer and reaction time in the event of an unplanned maintenance issue due to major equipment failure; all equipment had to be sourced within the European Economic Area (EEA).

Sheen notes the need for replacement equipment and expertise to be mobilised to site within 48 hours and a supply chain in place to achieve this as it is not practical to be waiting weeks for a replacement part to be made, accepted and then shipped across the world.

The shipbuilding market in Europe became depleted in the last recession; Dutch shipyard Van der Giessen, builders of the Isle of Inishmore went into liquidation in October 2003 and by 2005 there was little if any orders for new ferries in Europe, let alone across the world.

FSG, however, had carved a niche in the ro-ro (freight ferry) market having also built day ferries in the past for BC Ferries and Caledonian MacBrayne.

It was a pivotal time for FSG and allowed it to subsequently develop its product for the cruise ferry market, subsequently gaining orders from Brittany Ferries and TT Lines Spirit of Tasmania and Irish Ferries itself.

A pre-qualification process was undertaken with assistance of ship brokers which focused on relevant experience and subsequently a tender process was undertaken in-house.

FSG emerged as the leader, offering competitive advantage in terms of hydrodynamics and engineering.

FSG’s build time was also attractive (with the amount of pre-contract engineering that had been completed) with hull manufacture, and consequently the main machinery assembly, to be undertaken in-house and the superstructure subcontracted as three mega-blocks to two major subcontractors; Holm Construction for the centre block and Marine Projects Ltd, Gdansk, Poland, for the forward and aft blocks.

The product offered was effectively a combination of Irish Ferries’ technical and operational expertise integrated into a common product platform, the same process that the company had followed with the MV Ulysses before. The contract for new build 771 was signed on May 30, 2016.

List of acceptable classification societies


Sheen advises that the company had set out a list of classification societies acceptable to it and allowed FSG to select the most suitable society from the list.

DNV/GL had undertaken classification services on successful shipbuilding projects with FSG and working relationships were well established, projects included three ro-ro passenger ferries for British Columbia Ferries and four ro-ro ferries for Seatruck Ferries.

The company considered the benefits and constraints of real-time monitoring of equipment; while real-time monitoring has its place, Irish Ferries relies on the expertise of the vessel chief engineers and its on-board teams of engineering staff to monitor the status of equipment and manage a fuel efficiency for given sea conditions.

A diligent engineering team know their areas of responsibility intimately and can advise HQ of emerging trends. Sheen has full confidence in the vessel captains, chief engineers and their teams who keep the company informed of performance and progress via the outsourced technical managers.

The propulsion and power generation plant installed is an iteration of the reliable systems fitted on the MV Ulysses supplied by Caterpillar and MAK; there are four engines for propulsion, each developing 8,400kW.

Caterpillar MAK 8M43C main engines x two of four, Engine Room 1.

The engine room on the WB Yeats is segregated into two discrete parts, so if a catastrophic failure of power equipment were to occur, the ship would not suffer a single point failure of propulsion, power generation, control or switching equipment.

A key decision for Sheen and his team was to consider and select the most suitable fuel source, that is, continue using heavy fuel oil or move to liquefied natural gas (LNG)?

Since 2005, Marine Pollution (MARPOL) Emissions Control Areas (ECA) are in force since and the Dublin/Cherbourg route falls into the North Sea ECA; MARPOL Annex VI applies.

If heavy fuel oil was to be used, then in-line exhaust treatment and scrubbing after treatment equipment would be required.

Caterpillar MAK 8M20C generator set installation x one of three.

Sulphur content regulations


Furthermore, sulphur content regulations became more stringent on January 1, 2015, mandating a reduction in sulphur emissions from one per cent to 0.1 per cent, thus requiring shipping operators in SECA areas to purchase a more expensive and higher quality fuel oil.

Beyond this, on January 1, 2020, the global sulphur cap of 0.5 per cent comes into force.

There is a move by some ferry operators to LNG, however Sheen notes that there are considerable issues to overcome.

Locally, supply is a problem – Ireland only has a compressed natural gas network in place and does not have an established LNG network capable of supplying the fuel needs of the WB Yeats.

Marine reduction gear unit.

All staff on LNG tanker ships must have LNG training and there is debate as to whether LNG is environmentally friendly since methane emissions are not currently measured. Fuel energy density is also an issue.

Taking all of these issues into consideration, Irish Ferries elected to operate using fuel oil, thus maintaining a common fuel requirement across its entire fleet, it considers that from barrel to engine that this arrangement is the more environmentally sustainable method currently available (https://valuemaritime.com/scrubbers-would-aid-global-co2-reduction/).

It states that the WB Yeats is the first cruise ferry operating on the Irish Sea to meet the Safety of Lives at Sea (SOLAS) 2009 International Convention.

SOLAS prescribes safety requirements with respect to stability, fire protection, detection and extinguishing, safety of navigation and communication, carriage of dangerous goods among other things.

Maximum extinguishing capacity


For example, should a fire break out in an engine room, within 30 seconds of detection, the water mist fire suppression system will have reacted and reached its maximum extinguishing capacity.

Sheen notes that the reaction time using a water mist system is much faster than previous gaseous fire suppression systems, whereby all staff had to be evacuated from the engine room before a non-life-supporting gas would have been deployed to extinguish the fire.

Example of fire detection and control system – Deck 9 Detection Status.

The vessel also meets Safe Return to Port SOLAS regulations whereby if a fire occurs or a flooding of any single largest watertight compartments or ‘Category A’ space (areas of higher fire risk), the vessel is able to proceed to a safe port of refuge under its own power.

This requires all persons on-board to be accommodated in a safe area and services such as lighting, ventilation, sanitation, food, water and medical care must be maintained from incident occurrence to arrival at a safe port of refuge.

The WB Yeats is fitted out with marine evacuation and lifesaving equipment which is very expensive to procure and to maintain during the life of a vessel.

Irish Ferries has paid particular attention to this area to ensure that the vessel is fitted with compliant and reliable evacuation equipment in order to optimise life-cycle costs over the vessel’s life.

First steel cutting began on April 7, 2017; the keel of new build 771 was laid on September 11, 2017, with the time-honoured tradition of placing coins in the keel for ‘good luck’.

Ninety-five days later the hull was launched on January 19, 2018, and moved to a stabling dock for fit-out, all as per the builder’s milestone plan.

The three superstructure mega-blocks, each weighing up to 2,000 tonnes, arrived by barge from Poland (cabins had already been installed as completed modules effectively being wheeled into the accommodation sections and then secured in-situ) and were tandem lifted into position by floating cranes (capable of lifting 4,000 tonnes) thus completing the physical structure of the ship.

Installation of wiring was a major task; the superstructure mega-blocks were delivered as finished structures but not fitted out nor were any final electrical installations completed.

The reasoning behind this is the more connections and breaks there are in an electrical system, the more opportunity there is for failure, intermittent or sustaining defects to occur.

Major wiring to distribution boards was therefore completed afterwards with wires being pulled through the ship to minimise connectivity and maximise reliability.

In April 2018 FSG formally advised the company that delivery was delayed forcing it to cancel its maiden voyage from Dublin to Cherbourg on July 12, 2018. It had made contingency plans in the event of a delay and held back capacity on its Rosslare/Cherbourg vessel, the MV Oscar Wilde in order to facilitate disrupted customers.

FSG cited delays arising from deliveries of “interior components for public areas and on the electrical system installation in the hull and deck house”; it has also stated “all the key functions of our shipyard and our key suppliers are on the ship, and meet daily to ensure direct and efficient communication” as is normal practice on any major engineering project incurring delays.

Facilitate berthing trials


The WB Yeats was accepted by Irish Ferries on December 12, 2018, and sailed via Cherbourg and Holyhead to facilitate berthing trials before arriving into Dublin on December 20, 2018.

Due to the holiday period, safety certification was finally completed in Dublin, the vessel initially entered service on the Dublin/Holyhead short sea route on January 22, 2019, which proved the vessel in service before moving to the Dublin/Cherbourg operation on March 15, 2019.

Feedback from customers after service introduction was positive and there has been very strong demand from the commercial market for sailings around weekends.

Following feedback regarding food offerings on board, Irish Ferries will redesignate part of the ample freight drivers’ lounge to become a bistro style food outlet, thus offering a complete range of catering from barista style cafe to waiter service restaurant.

The end product is that the WB Yeats now offers a very high-quality direct service between Dublin and Cherbourg meeting the latest safety and survivable standards in modern ferry design.

It provides Irish exporters, importers and leisure travellers with a direct link between Dublin and the EU mainland free from Brexit risk and associated potential transit delays.

(MD Andrew Sheen will facilitate an IEI engineering visit to WB Yeats and details will be published on the IEI website.)

Author: Derek E Byrne BEng (Hons) MBA Cert MIEI.

http://www.engineersjournal.ie/wp-content/uploads/2019/09/a1-32-1024x576.jpghttp://www.engineersjournal.ie/wp-content/uploads/2019/09/a1-32-300x300.jpgDavid O'RiordanMechenvironment,marine,transport
A modern cruise ferry is a complex package of engineering, comprising of safety systems, structural design, installed power, command and control systems, each of which are significant engineering projects in their own right, writes Derek Byrne. So how is a reliable new ship engineered, designed and delivered to provide the...