Thread: The end of cruise ships, as we know them?

Sounds like exactly why I used anticon insulation under my shed roof.

I have seen heavy rain inside 3 or 4 sheds over the years.

Had me stumped the first time but didn't take long to figure out why it was happening.

cheers, DL

Originally Posted by 350RRC

Sounds like exactly why I used anticon insulation under my shed roof.

I have seen heavy rain inside 3 or 4 sheds over the years.

Had me stumped the first time but didn't take long to figure out why it was happening.

cheers, DL

Not such a problem in Perth

Originally Posted by PerthDisco

In my experience big ships are like hotels in that they mainly by law don’t have opening windows (portholes) to introduce a certain amount of fresh air (and humidity). So they run permanent extraction from the bathroom and the door will be cut short or have lower louvre to enable movement (extraction) from the room. The zone / floor / deck section will have a local AC unit with ducted supply of air con to the room/s it serves typically via a chilled water system (with pipe work immaculately insulated to avoid condensation) with the noisy chiller compressor system in the engine room or basement and pumps running the chilled water around to each unit. Local cabin temperature control (on fancy setups) is +/- a few degrees of the central system temp via a small heater element on the individual cabin supply. The ship’s engineer determines the master temperature.

Seperate to all that is a make up air unit/s that treats the outside air to inject a specified percentage 10-40% to the system to balance the extracted smelly air from the dunnies. Smelly extraction air from dunnies, galley and black water tank goes up the mast to the atmosphere. Everyone starts off wanting a lot of make up air till they hear the cost........

You need some fresh air and humidity to avoid people waking up with a super dry throat at night when sleeping (sound familiar?) as a 100% recirculated system will eventually dry the air out not to mention be stale and unfriendly (cheapy small boat systems are like this with individual cabin units and often no make up air). At night, with no sun on the window or wall and once all the hotel / boat doors are kept shut the air conditioning starts to work really well!!

The make up air unit has to achieve this comfortable level of humidity and unlike a hotel in a fixed environment needs to cope with both high humidity (Florida/ Asia / Kimberley / Caribbean) and low humidity (New Zealand / Canada) cruises. An enormous amount of water is removed in high humidity areas.

Make up air unit/s can be located in various deck cabinet locations drawing air in from outside and distributing to the cabin zone AC units.

This capability drives the size and cost of the units. The more make up air % the bigger the make up air unit the more electrical power the bigger generators, etc etc. All this creates a perfect war when the engineers say they need a bigger engine room and to delete a cabin or 3 to fit in the bigger plant and associated make up air throughout the boat. The engineers rarely get what they want in front of the sales guys so compromise is built in from day one.

I used to see customer specs stating the marine air conditioning system needed to cover -15 degrees to 50 degrees with 50-90% humidity assuming the different locations the boat would visit. The air conditioning contractor quotes would come back astronomical with an incredible plant size and power demand. Then I learnt something interesting........

You can’t have high temp and high humidity coincident at same time. Singapore has super high humidity in the day but the temp never more than low 30s. The Middle East may show very high humidity in the early morning but by midday at 45+ degrees the humidity burns off to lower levels. The range of temp and humidity extremes published do not happen at the same time. It’s a law of thermodynamics thing.

On this basis you can specify a more affordable system that will cope.

On top of this a boat needs a completely pinned, sealed and taped thermal insulation lining (seperate to A30 or A60 fireproofing insulation to fire risk areas) on the inside of the entire steel or aluminium structure between the structure and any air conditioned cabin or space. Without this in hot / humid areas the hull sweats causing an internal rain and enormous condensation / stink / mould / destruction/ rot issues. Having a sexy dark hull colour will greatly exacerbate the internal / external temp differential with the sun on it. When you next jump on a cheaply built ferry in Asian waters you will know what I mean as easy to save money on that insulation.

That is how I would have thought it would work,but that definitely isn’t the way the system is on the Tassie ferry operates,by their reports.

It should also be noted that the Tassie ferry stays in the one area,so a specific system could be engineered for the climate in that region.

The two vessels known as the Spirit of Tasmania I and II were originally constructed in Finland and operated between Greece and Italy, so I don't know if that would affect the design of their aircon.

I see the Spirits are moving to Geelong in 2022 for 30 years after Tasmania accused the Port of Melbourne of 'price-gouging'. The Geelong site will have better facilities including marshalling for 600 vehicles, which should end the congestion in Melbourne, where vehicles jammed local streets.

Learn About Our Ships - Sailing Experience | Spirit of Tasmania

Merchant seamen around the World are in limbo, as countries refuse normal crew changes.



More than 1 million seafarers are trapped working on cargo ships around the world due to the coronavirus

Originally Posted by bob10

Merchant seamen around the World are in limbo, as countries refuse normal crew changes.



More than 1 million seafarers are trapped working on cargo ships around the world due to the coronavirus

Poor buggers, I can't see a problem testing 15-20 people at a time to allow these truckies of the sea ashore/change over crews, As long as they disembark /join the ship in their own countries without the need for international air flights.

Also lots of cruise ship crew isolated around the world, unable to get home.

Originally Posted by DiscoMick

Also lots of cruise ship crew isolated around the world, unable to get home.

Not anything new to ships crews.
Many spend up to 10 months at sea.