Taming ocean swells for cruise ships – the price is too high

In our previous post, we looked at the critical risk strong winds would pose for cruise ships berthed in Yarra Bay.

In this post, we look at big seas – storms and ocean swells – and explain that while they can theoretically be controlled in Yarra Bay, the consequences are unacceptable – for Yarra Bay, for the Port Botany shipping channel and for Kurnell.

Let’s get started!

Yarra Bay is fully exposed to swells from the south east (red arrow). Southerly swells are also significant, as they curl into the bay (orange arrow):

To protect Port Botany’s Brotherson Dock from these swells, the Molineaux Point break wall was built. It arrests the swells and dissipates their energy as they run south-west to north-east along its face (green arrow in diagram above).

However large swells associated with storm events are only partially dissipated. When they hit the Molineaux Point break wall (red arrows), some of their energy is redirected across Yarra Bay (orange arrows):

This is why Yarra Bay has surf, on days when big seas cause Sydney’s ocean beaches to be closed:

Surfing on Yarra Bay, during storm event, 4 June 2019. Image © & courtesy Bill Burst.
Surfing on Yarra Bay, during storm event, 21 August 2019. Image courtesy & © Brook Mitchell & Sydney Morning Herald.

And why the groyne in front of Yarra Bay Sailing Club can be over-topped by large breaking waves:

Information from port community sources indicates that the Berejiklian Government’s “Strategic Business Case” proposes a finger wharf to accommodate cruise ships extending into Yarra Bay from Bumbora Point.

Large swells, hitting the Molineaux Point break wall and rebounding across Yarra Bay would present a major risk for this finger wharf (dark red line), and for ships berthed at it (blue lines):

Option 1 – a finger wharf extending into Yarra Bay from Bumbora Point

The ships would surge at their berths, and to prevent damage to them and to the wharf, they would need to leave their berths. Once they had departed, the wharf would be fully exposed to the swells and could suffer significant damage.

To protect the finger wharf, an island breakwater that would prevent swells entering Yarra bay would need to be constructed (green line), almost at right angles to the direction of the swells (red arrows):

The island breakwater could not be at right angles to the swells as it would protrude into the Port Botany shipping channel. But it would need to extend as close to the Molineaux Point break wall as possible, in order to prevent the swells reaching the break wall and being redirected towards the Yarra Bay finger wharf.

Locating a breakwater here has major consequences for Yarra Bay

Firstly, it would restrict access to the finger wharf to a narrow channel (orange arrow, below). Dredging of the (shallow) water close to the breakwall would be required and navigation of mega cruise ships through this tight access passage with strong tidal flows would be challenging. Keep in mind that cruise ships have inflexible schedules – to meet their passengers’ expectations, they must berth at dawn and sail at dusk.

Secondly, the breakwater would drastically restrict the tidal flow of water in and out of Yarra Bay, creating a narrow channel between the breakwater and the Yarra beach shore (green arrow, above). This would result in dangerous currents and deep channels close to the beach, scouring of the seabed and sand depletion from the beach. Yarra Bay beach would become dangerous, particularly on the ebb tide. The sailing club would no longer be able to operate and the Maroubra and Coogee surf clubs’ surfboat and IRB training would be compromised.

The consequences for the Port Botany shipping channel are equally severe

Sand dragged from Yarra Bay by tidal currents past both ends of the island breakwater (red arrows) would end up in the shipping channel (gray zone of chart) and would require frequent dredging to keep it clear:

Just as swells are redirected from the Molineaux Point break wall, they would also rebound from the island breakwater:

This would result in confused cross seas in the shipping channel and would cause passing ships to list side to side and plunge bow to stern. This is highly undesirable for large, deep draughted vessels with minimal Under Keel Clearance (UKC) and could cause hull damage and even groundings.

The confused seas would also greatly increase the risk of capsize faced by recreational fishing vessels.

And there are consequences for Kurnell …

After traversing the shipping channel, the redirected swells would strike the Kurnell shoreline:

Damage to the beaches could be expected in the vicinity of the Captain Cook monument. Further to the west, oil tankers at the Kurnell oil products terminal jetty and the the swinging buoy north of the jetty would also be impacted by the rebounding swells.

Conclusion

Yarra Bay is highly exposed to south and south easterly ocean swells that can occur at any time of the year. To protect mega cruise ships berthed at a large wharf in Yarra Bay, a massive breakwater would need to be constructed across the wide mouth of the bay. The cost of this structure and its impact on Yarra Bay, the Port Botany shipping channel and the Kurnell shoreline are simply too high. The ill conceived proposal to construct a mega cruise ship terminal in Yarra Bay must be abandoned now.

Note on options

The mega cruise ship wharf location design we have illustrated in the diagrams above is based on information we are receiving from the port community and our own calculations regarding depths in various parts of Yarra Bay and the orientation need to protect berthed ships from the extremely strong winds experienced at this exposed site.

Two other options are provided below. Both would require the protection of a massive island breakwater, identical to the one illustrated above.

Option 2 – a shorter finger wharf with one ship berthed on each side
Option 3 – a quay parallel to the Molineaux Point break wall

Comments on this article (from our Facebook page)

Jean-Francois De Florette: I regularly paddle an ocean ski in Botany Bay and in particular Yarra Bay when conditions offshore are too big … A few weeks ago I paddled 4-5 metre swell in Yarra Bay!

To give you perspective, when I was in the trough of the wave, the tops of the cranes at Port Botany would disappear in front of my eyes. Whilst this was fun for me, I could not stop thinking that Gladys would have to build a bigger (sea)wall than Donald’s…!

Grant Rogers: In really big swells we couldn’t see other sailing competitors and they had nine metre tall masts.

Natalie Rogers: Grant Rogers in a really REALLY big swell we had waves hitting the centre of the main sail!!

Rodney Rat Ardler: Some days the waves make it to the road [ Prince of Wales Drive ] – they go over that wall [Molineaux point break wall ]

Wind poses grounding risk for cruise ships in Yarra Bay

Nature poses two major threats to a Yarra Bay mega cruise ship terminal. The obvious natural threat is sea state, as the site is fully exposed to the open ocean and in a direct line to south-easterly swells:

Botany Bay heads from Molineaux Point breakwall; a cruise ship berthed in Yarra Bay would share this view, which illustrates how exposed the bay is to sea state.

In another post, we look at the threat posed by swells. In this post, we will examine the less obvious threat posed by strong winds.

Mega cruise ships are very tall – the height of a 17 floor building – and slab sided:

Mega Cruise Ship Oasis of the Seas on left (port) side of a finger wharf

And they are very long (at 348 metres, Ovation of the Seas is as long as the eastern side of Hyde Park south – Liverpool Street to Park Street):

Ovation of the Seas is as long as the eastern side of Hyde Park south

A floating object of this shape with these vast dimensions is highly vulnerable to the force of strong wind.

Mighty Ships documentary – Captain of mega cruise ship Quantum of the Seas, whose departure has been delayed, says to camera: “Wind is our biggest enemy.”

Yarra Bay is not protected by hills or ridges in any direction and strong to gale force winds impact the bay in all seasons of the year and from five directions:

  • south – any time of year
  • south east – any time of year
  • south west – in winter and spring
  • north west – in spring and summer
  • north east – in summer
South-westerly on Yarra Bay, 4 June 2019, from Molineaux Point break wall. Image courtesy Cheryl Rennie

There is a real risk that a mega cruise ship, berthed at an exposed wharf in Yarra Bay, could be hit by winds so strong that it would break its moorings. If not able to manoeuvre quickly enough under its own power, the gigantic ship could be pushed by the wind and run aground in the bay – in front of Yarra Bay beach or on the Port Botany breakwater, somewhere between Molineaux Point and Bumborah Point.

To gain an appreciation of the real possibility of such an incident, it is worth recalling the events of the night of 14 October 2014 at Brotherson Dock in Port Botany. A gale force southerly arrived suddenly about 9:00 pm. The winds reached 126 kilometers per hour – category 2 cyclonic strength – just before 9:30 pm and broke the moorings of the Kiel Express, a large container ship berthed at the DP World terminal on the south eastern side of Brotherson Dock.

The Kiel Express swung out of control across Brotherson Dock and its stern collidedwith Safmarine Makutu amidships, another large container ship which was berthed at the Patricks terminal on the opposite side of Brotherson Dock.

Stern of Kiel Express collides with Safmarine Makutu amidships. Image courtesy & © Sydney Morning Herald.

While swinging out of control away from the wharf, the bow of the Kiel Express cut the bow mooring lines of a third large container ship, the OOCL Hong Kong, which was also berthed at the DP World terminal. As the bow of the OOCL Hong Kong swung out into the dock, its stern was pushed into the quay and was damaged by bollards on the wharf.

The bow of the OOCL Hong Kong swings out into Brotherson Dock after its bow mooring lines were cut by the out of control Kiel Express (foreground). Image courtesy & © Sydney Morning Herald.

The OOCL Hong Kong was brought under control by tugs and had to be held by them throughout the night, while the Kiel Express was only brought under control by allowing it to lie alongside the Safmarine Makutu for the rest of the night.

Kiel Express is secured alongside Safmarine Makutu while all available tugs attempt to control the OOCL Hong Kong. Image courtesy & © Sydney Morning Herald.
As dawn breaks, the Kiel Express remains alongside the Safmarine Makutu. Image courtesy & © Sydney Morning Herald.

The Safmarine Makutu and the OOCL Hong Kong suffered damage affecting their seaworthiness, including damage to the hulls and navigational lights. The Australian Maritime Safety Authority (AMSA) required these ships to undergo repairs before leaving port.

On the night of 14 October 2014, it was possible to bring under control two very large ships with broken mooring lines because:

  • there was some degree of shelter within Brotherson Dock
  • six powerful tugs could be mobilised rapidly and being berthed in Brotherson Dock, were immediately able to attend to the stricken ships
  • within the dock, and due to the direction of the wind, there was nowhere for the ships to run aground

In Yarra Bay, on such a dangerous night:

  • there would be no shelter
  • the ships would be twice as large
  • tugs would not be at hand – they would be half an hour away
  • there would be no dock with water of uniform depth and the ships would be blown on to the beach or the Molineaux Point breakwall

We leave the consequences to your imagination. As a guide to one possible outcome, you may recall the grounding of the Pasha Bulker at Nobbys Beach Newcastle in 2007, when caught at the port’s weather-exposed anchorage by the onset of gale force winds:

Pasha Bulker aground on Nobbys Beach, 1 July 2007. Image courtesy of & © NSW Maritime.

Note: The very dangerous nine hour incident in Port Botany on 14-15 October 2014 was reported in:

Comments on this article (from our Facebook page)

Josie Gilbert: 5 boats per year wash up on the beach if not more. Thus moorings being closed for application now. Very bloody windy here.

Sloop blown off its mooring; aground on Frenchmans Beach, 2018. Image courtesy Josie Gilbert

Cheryl Rennie: A most professional and correct report by Peter! It is what the sailors from Yarra Bay Sailing Club have been saying all along!

Michelle McKenna: Someone I know who has worked in and on the bay extensively and knows it inside out laughs when I talk about the terminal, pretty much for this reason. I hope he is right.

Anthony James: Locals know how wild Botany can be. Again and again. Rough is common in the bay.

Fishing boat blown off its moorings by a south-westerly; aground on Frenchmans Beach, August 2017

Mark Baker: The container ships are not moored in Yarra Bay, regardless, they have broken their moorings on multiple occasions, while actually being sheltered BEHIND the Yarra Bay breakwall, and caused significant damage to themselves and other vessels.

Tugs attempt to control OOCL Norfolk after it broke its mooring lines in high westerly winds at Patricks terminal, Brotherson Dock in October 2013. The bow almost touches the opposite quay, while the stern almost strikes a Maersk line vessel. Image courtesy felixstowedocker.blogspot.com

I have lived in La Perouse for the last 10 years, every time we have a significant weather event, boats moored in Frenchman’s Bay break their moorings and get thrown up on the beach or sunk, the logic I am using is based on observation and experience.

Catamaran blown off its moorings by a south-westerly; aground on Frenchmans Beach, 4 June 2019. Image courtesy Mark Baker

Mark Baker: This is what you get when we get an East Coast Low in Frenchman’s Bay, boats breaking moorings and ending up on the beach, now imagine this was a giant cruise ship with thousands of people on board, it’d be smashed onto the beach or break wall without fail, hello disaster!

Sloop and catamaran blown off their moorings by a south-westerly; aground on Frenchmans Beach, 5 June 2019. Image courtesy Cheryl Rennie

Randwick Council united in support of motions on Yarra Bay

At its meeting on 30 April, Randwick City Council carried unanimously two motions concerning the Berejiklian government’s proposal to construct a mega cruise ship terminal in Yarra Bay:

Motion 18/19 – Cr Said – Update on Opposition to Proposed Passenger Cruise Ship Terminal

For the address in support of the motion by Maria Poulos of Save the Bay Coalition, click here.

Motion 19/19 – Cr Said – Apply for National Heritage Listing and Grant Program

For the address in support of the motion by Peter Fagan of Save the Bay Coalition, click here.

Save the Bay Coalition acknowledges the support of all Councillors for these motions. We look forward to working with Councillors and staff as the campaign to stop this destructive development proposal enters its next phase.

Randwick Council to consider two motions on Yarra Bay

The agenda and business papers for Randwick City Council’s meeting next Tuesday (30 April) are here.

There are two motions of concern to Save Yarra Bay members and supporters:

Notice of Motion from Cr Said – Update on opposition to proposed passenger cruise ship terminal (page 293)

Notice of Motion from Cr Said – Apply for National Heritage Listing and Grant Program (page 295)

To demonstrate our concern over the future of Yarra Bay and to support those Councillors voting in favour of Councillor Danny Said’s motions, please (if you can) attend the Council meeting on on Tuesday 30 April – 6 pm, Council Chambers, 1st Floor Randwick Town Hall, 90 Avoca Street Randwick.

Save the Bay Coalition representatives will speak to both motions.

Should you wish to make representations to your Councillors on these matters, their contact details are here.

P.S: Councillor Said is also active on behalf of the local community with another motion:

Notice of Motion from Cr Said – Development applications in Banksmeadow (Bayside Council) (page 319)

Port Botany is congested NOW – without cruise ships

Botany Road, in the vicinity of the Berejiklian government’s proposed mega cruise ship terminal, is already extremely busy in daylight hours.

If a mega cruise ship terminal is jammed into this already overcrowded precinct, expect extreme traffic congestion, frustration, accidents, delayed starts to bus excursions and bus excursions reaching the dock after ships have departed.

Queues build rapidly at peak times and when there is a delay within a terminal.

Semi-trailers approaching from both directions on Botany Road queue to enter the DP World terminal.
Semi-trailers queue in Botany Rd, waiting to enter the DP World terminal.
Queue in Botany Rd for the DP World terminal.

We predict that the mega cruise ship terminal will be at the end of Bumborah Point Road. Coinciding with morning and evening peaks, two mega cruise ships at a Yarra Bay terminal would require around 100 coaches to enter and leave Bumborah Point Road each morning and evening.

Right hand turns into an out of Bumborah Point Road are already very busy with container and bulk liquids truck movements – and STA buses from the Port Botany bus depot trying to keep to timetable. Coaches, taxis, Ubers, private vehicles and delivery vans and trucks will all have to join the queues.

Semi-trailers and an STA bus queue in Botany Rd, waiting to enter Bumborah Point terminals and the STA Port Botany depot.

Randwick Council to vote on National Heritage Listing for Yarra Bay

On 30 April, Randwick City Council Deputy Mayor Danny Said (Labor, South Ward) will present a motion to the Council meeting. The motion will recommend the nomination of Yarra Bay for inclusion on the National Heritage List.

Randwick City Council has already applied to the NSW Government to have the area included in the State Heritage Register.

The Sydney Business Chamber clearly sees heritage listing as a real threat to their plans to transform Yarra Bay for the benefit of the foreign-owned cruise industry. Their director of policy Chris Lamont told the Daily Telegraph:

“It would be disappointing if the heritage listing process was being abused to exclude necessary and important considerations around a new cruise ship terminal.”

A representative of Save Yarra Bay will speak in favour of the motion. Will the Sydney Business Chamber find someone to speak against it? And how will Liberal Councillors vote? It should be an interesting night.

We will publish Councillor Said’s motion as soon as it is available. Before the meeting date, Save Yarra Bay Coalition members and supporters are encouraged to make representations to Councillors – their contact details are here.

If you can, please also attend the Council meeting on Tuesday 30 April – 6 pm, Council Chambers, 1st Floor Randwick Town Hall, 90 Avoca Street Randwick.

Randwick Council continues fight to Save Yarra Bay

The Mayor of Randwick City, Councillor Kathy Neilson has written to the Minister for Transport and Roads, Andrew Constance and the Minister for Jobs, Investment, Tourism and Western Sydney, Stuart Ayres, to request a meeting to discuss Council’s (and our) concerns and objections to the Yarra Bay mega cruise ship terminal proposal. This includes a request for the release of the Strategic Business Case.

Mayor Neilson’s letter to Andrew Constance is here (the letter to Stuart Ayres is identical).

Mayor Neilson has also requested a meeting with Peter Collins who led the Cruise Industry Reference Group. The recommendations of the group were included in the NSW Cruise Development Plan and Mayor Neilson is seeking a briefing on these recommendations.