Casinos conjure up images of glamorous hotels and the 24/7 action of Las Vegas, but there's a unique form of gambling that takes place far from land: on cruise ships.

Although you'll find some professional gamblers at sea, most people who gamble on cruises are occasional at best. The casino offerings on most cruise lines reflect this, with a limited number of table games and a focus on slots.

However, spending time in the casino can be an enjoyable part of a cruise holiday for many people. As with all gambling, it's important to be aware of what's at risk - and in this case, especially to set a budget so you know how much you're prepared to lose.

Here are 10 important tips to know before gambling in cruise casinos:

The odds aren't so good

It's no secret that casino odds aren't in your favour on land, but this is even more true at sea. For example, in Blackjack, where the odds of winning on land can be more favourable due to competitive regulations, cruise casinos often have rules that favour the house even more.

"Cruise casinos offer some of the worst payouts you'll find," says Tanner Callais from Cruzely. The expert singled out Blackjack as a typical case of worse gambling conditions at sea. According to him, cruise operators offer payouts of 6 to 5 instead of the more usual 3 to 2: "If that doesn't sound like much, consider that a $10 bet would pay $12 in blackjack, instead of $15 under typical rules."

Limited choice of table games

Cruise lines tend to fill their casinos with lucrative slot machines, something that attracts more casual players. This leaves less room for table games like poker and blackjack, although roulette wheels are generally well represented.

There may only be one or two tables for each game, so the variety and availability is significantly less than what you would find in a large land-based casino.

Opening hours vary considerably

Although most cruise facilities are open throughout the day, the casino - like the shops on board - is an exception. Because of tax rules and regulations, casinos are only open when the ship is at sea.

On sailing days, you'll find slot machines open throughout the day, possibly up to 24 hours. Table games will start around lunchtime and stay open until late. Whenever the ship is in harbour, the casino will be closed.

Opening times will be announced in the daily programme, which is usually delivered to your cabin the night before or is available on the on-board app, if there is one.

You could win a "free" cruise

On land, frequent players often receive discounted accommodation, meals and other benefits to encourage them to return. These loyalty programmes also exist on ships: it is possible for frequent players to accumulate points through their play, which can be redeemed for various benefits, including future cruises.

Remember that in order to reach the amount of points needed for such premium benefits, you'll need to spend a considerable amount of time playing. If that's your goal, choose an itinerary with more days at sea to maximise your time in the casino.

It's less intimidating

If you've always wanted to learn poker or blackjack, but were intimidated by the idea of a live casino, a cruise ship could be the perfect opportunity for you.

Most cruise operators with casinos offer sessions for beginners to learn in a comfortable, no-pressure environment. In many cases, those who take part in the class can receive some casino credit to use for real, so it's worth keeping an eye out for any sessions advertised in the daily programme.

During normal gaming hours, sea casinos generally have a more sociable atmosphere than land-based ones, with lower table limits that encourage more casual players.

Free drinks are rare

Continuing to play the slots or sitting at the poker tables in Vegas will probably result in offers of drinks, albeit at the cost of a tip. But on cruises, this doesn't usually happen. There is usually a bar in the casino, and waiter service is a probability. However, drinks will almost always be charged for, unless you have a drinks package, of course.

Some cruise lines offer a free drink after a certain amount spent, usually US$100 on slots, so check the cruise line's policies to make sure you don't miss out on this opportunity.

You can't play with credit on board

Do you have a large amount of credit on board and are thinking of putting it all in the black? You'll be out of luck.

Most cruise lines don't allow you to use on-board credit to gamble. Even if you have some in your account, any deposit you make in the casino will be charged to your credit card.

Cruise casinos are becoming non-smoking

Smoking and casinos go hand in hand. Traditionally, a ship's casino was one of the only indoor spaces where smoking was possible. Some operators still allow this, but things are changing fast.

On MSC Euribia, MSC's newest cruise ship, smoking is not allowed on the entire casino floor. There is an outdoor terrace accessible only from the back of the casino.

US age laws don't always apply

Depending on the state, some US citizens under the age of 21, which is when the age of majority begins in the United States, may not be able to gamble in land-based casinos. On a cruise, these laws don't always apply.

All the major American cruise lines allow anyone over 18 to play, with the exception of some US-focused itineraries, such as Alaska, and some Caribbean cruises. If in doubt, check the cruise line's policies before booking.

Withdraw before disembarking

Although you can gamble using your cabin account, cruise ship casinos generally only pay out in cash.

If you get lucky at the machines or tables, make sure you cash out before you disembark. In fact, this must be done before the casino closes on the last night. If you miss this deadline, you won't be able to claim your winnings.

Finally, it's important to remember that visiting the casino should be an enjoyable part of your cruise holiday. If it stops being fun or you're losing more than you intended, stop. There are plenty of other ways to spend your time and money at sea.

By David Nikel