It depends on what you mean about living aboard your catamaran, marina living is totally different from cruising. Let's tackle living aboard in a marina….

Now in a marina for starters many marinas charge double for accommodating your catamaran, some will charge you even double, this has been known for many years, nothing new, but this depends on where you are in the world the same if you're renting a flat in Kensington or Chelsea in London or Poole in Dorset England, Cannes or Monaco you will be paying a premium….

Many marinas will not charge you any more than a monohull especially if you find a shallow berth in the marina where a monohull does not dare to tread.
A cat will sit comfortably on the end of a T pontoon which should not be charged at a premium.
There are plenty of marinas that are catamaran friendly in various parts of the world if marina living is what you want, and a catamaran is a lot more spacious and the beam will take up two regular monohull berths so in a way you can expect to pay more.
Let's face it, compared to the same length of an equivalent sized monohull a 40ft cat will be the equivalent of a 60 ft monohull with all of the advantages of catamaran hulls.

Also you can take advantage of all of the marina services, some have swimming pools, club houses, water and electric, bars restaurants, you can do day charter based from the marina, you can use your skills fixing other people's boats if you can learn GRP repairs, engine maintenance etc, the wife may have hair dressing skills or make up, nail technician etc, you can keep your car there nice and secure, you can even work from there. It's normally a safe and secure environment. Find out the rent on a gated apartment in a similar complex anywhere in the world!

If you enjoy marina life why not, but that is being a waterside apartment. Some people turn right out of the shipyard find happiness in the first marina they get to, make new friends and stay put, why not.
It's the same as paying rent or a mortgage, but in a sunny location by the water and if you get tired of the neighbours and marina gossip you can crank up the engines and move!

I had a customer that purchased a 43 ft catamaran who kept it in St Katharine Docks in Docklands London years ago, running a Recruitment Company in the City from the catamaran who was paying 400GBP per month in the heart of the city, where an apartment would have cost 4,000 GBP per month!

Mooring: €12,000 - 24,000 per year depending on location
Engine maintenance: €3,000 per year approx
Repairs: €2,000 per year approx
Antifouling / lift out: €1,200 per year approx
Electric and water: included
Insurance: 1-2% of the boat's value
Fuel: depends on use

Cruising Live Aboard

This is where a catamaran makes sense, depending if you have expensive taste, Champagne taste and beer money comes to mind. You have endless bars and restaurants to spend your money or you can live quite frugally, you have a water maker so no need to come into a marina that often, you have showers, toilets, an oven and hob, fishing tackle for fresh fish, a fridge and freezer, a decent tender to come ashore without paying marina fees and anchoring off the beach or in the creek or estuary in shallow water. In the BVI Island hopping, or in the Med. Sure things will break and sometimes go wrong but on the whole much cheaper.

Mooring fees: maybe €2,000 per year if you want to treat yourself
Repairs: maybe €4,000 per year approx, as you will be moving more and things break
Electric and water: zero
Insurance: 1-2% of the boat's value per year
Fuel: depends on use
Starlink: €60 per month close to shore

It all depends on your lifestyle, but it is a sailing boat, free power from the wind!
Even on a power catamaran it is much more economical on fuel compared to a conventional monohull, with less resistance, smaller engines and greater range.

Free fish, free lobster, free Calamari, free crabs, maybe sailing not so expensive!

Of course if you spend most of your hours in the beach bar, eat in expensive restaurants it is going to be expensive and it's about lifestyle, but the same as living in a house or an apartment but the house does not sail to windward very well!

Living Aboard a Multihull: Is It Expensive?

Cruising Live Aboard

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