I'm a cruise ship officer. I love my job, but it's not the constant vacation that people assume.

• Cruise officers are in charge of the safety and navigation of massive ships carrying thousands of passengers.
• Third Officer Natalie Grillo said the position is extremely rewarding and requires a strong work ethic.

This as-told-to essay is based on conversations with Natalie Grillo, a 25-year-old third officer at a major US cruise line. She has chosen to exclude her employer's name due to the company's media policy, but her employment has been verified by Insider. Her words have been edited for length and clarity.

I think a lot of people have this misconception that it's easy to work on a cruise ship because they think we're vacationing and not actually working. They don't realize the amount of work that goes into making those vacations for other people.

Whether you're a dishwasher, housekeeper, or an officer like me, you're doing hours and hours of labor, all for the benefit of the guests, with rarely any days off. I've worked in the oil field, on research vessels, and on small boats, but working on a cruise ship is the most difficult job I've ever had.

As a Third Officer, my job is half safety and half navigation. I'm living and working onboard cruise ships anywhere from six to nine months of the year. My typical contract is two to three months with two months of vacation in between.

My favorite part of the job is how challenging it is. You're constantly working your way up to becoming the captain. Every day there's something new to learn and that's really important for me. As you learn more, you get a fuller understanding of everything that's happening on the vessel.

Working on a cruise ship has also allowed me to meet people that I would have never met otherwise. I've never been to South America or Indonesia, but I've met so many people from those locations and have gained a better understanding of what their lives and culture are like. It really gives you a better worldview.

I often have to choose between sleep and social life

My least favorite part of the job is the sleep schedule. I wouldn't give up my job for the world but I do wish that there were more hours in the day because the job legitimately never stops. You work seven days a week and there are no days off until your contract is over.

Cruise ship officers are divided into three different "watch groups" that are assigned two shifts that are four hours long. You either work from midnight to 4 a.m. and then noon to 4 p.m., 4 a.m. to 8 a.m. and then 4 p.m. to 8 p.m., or 8 a.m. to noon and then 8 p.m. to midnight.

Getting enough rest is all a juggling act — do I want to sleep or do I want to go out? Do I want to go to the show or do I want to watch a movie? But you make those deals with yourself of how much am I willing to give to get.

I see my friends when I can but oftentimes my shift schedule is a lot different from theirs because most crew work during the day. Social life onboard really just depends on the job or the shifts that you have.

The crew bar opens at 10 p.m. and stays open until about two in the morning. If you want, you can have your friends over in your cabin, or you can hang out and watch a movie. There are also crew social events you can attend like parties in the crew bar. I personally don't really go out much because I prioritize my sleep, which I don't mind.

I'm in charge of the safety of thousands of passengers

During your watch, it's your responsibility to ensure that the ship is following the chartered course that has been approved by the navigation officer, the company, and the captain. You need to make sure that the ship is following safe navigation in accordance with all the local laws and traffic rules.

After my four-hour watch shift, I start the safety inspections of the equipment that I'm responsible for (like fire extinguishers) or go on my safety rounds, which is when each officer oversees a deck or two. During safety rounds, I take a look at all the safety equipment that's on those decks, make sure certain doors are locked properly, and check the fire stations and sprinkler heads — anything that could infringe on the safety of the vessel.

We're also trained to handle a number of emergency situations, including fires, collisions, grounding, piracy, man overboard, or an abandon ship order.

Working on a cruise ship has been the most difficult job I've had because the scope of responsibility is larger compared to other jobs in the maritime industry — you're not just dealing with your crew members anymore, you're also dealing with your guests. Having that responsibility of 3,000 people while you're navigating obviously makes it a little bit more intense.

We have special privileges like our own cabins, bar, and mess hall

One of the biggest benefits of being a cruise ship officer is that you get your own cabin and bathroom, while other crew members have to share bunk rooms with a roommate.

Because I have a single cabin, I can have a guest on board, something workers who share a cabin and bathroom can't.

For staff, there are two different places to eat: a mess hall for officers and a mess hall for general crew. The food is exactly the same. The officer mess hall is just smaller and sometimes there's a nicer tablecloth — that's really the only difference.

But officers have more privileges when it comes to dining in guest areas. General crew members may not have that opportunity and might get their requests denied. I probably wouldn't because of my position.

Officers also make more money than most crew members. But then again, you also have a lot more responsibility. I get paid around $1,700 a week (pre-tax) and that includes my vacation pay. It's a salaried position so I don't make any hourly overtime. Officers also get a merit-based percentage increase each year if the company does well.

I wish cruise corporations would listen more to crew members

I wish that the companies would listen to crew members' concerns more and take them more seriously. I think it would drastically improve workers' lives. All they're looking at is profit when the people who are making the profit for them aren't necessarily getting all of the benefits that I think they deserve.

Some people I know have worked 10 to 15 years on cruise ships. That's over a decade of their life that they've spent away from their life on land. They send money to their family back home and they're working hard hours and hard labor to do that.

If they made the ship a little bit more comfortable for the crew — even through little improvements like buying new sheets — it would improve their lives exponentially, to a point where it would help them give better service to the guests.

It can be hard to balance your life at sea with your life on land

Being away from your life on land for months at a time is definitely difficult. You really need to have people who support you and understand the job and the life that you've chosen. When you're away that long, it almost feels like the land side of your life disappears — whatever is happening on shore takes a backseat to your job.

When I'm away for my next contract, I'm going to be missing two weddings. It's not that these weddings aren't important to me, I want to be there, but my friends understand why I won't be there.

When I return home to New York, it can be a little difficult to transfer between work mode and home mode after working constantly seven days a week. On the ship, you're always constantly on task and then you come home and you've got nothing to do.

It's an amazing career if you understand what you're getting into

I think that people might underestimate the difficulties of working at sea.

I know some people that have worked in the industry for 20 to 40 years and they love it. Some people are just built like that. And then there are some people who quit after a year because they don't really understand what that work-life balance is actually like.

I think it's a great career and that it's an incredibly fulfilling career for myself. But it's really what you make of it. So if someone is to choose this as their career, they should go into it knowing that it's not like working an office job when you're at a computer all day — you really need to work hard and be aware at all times.

Do you work on a cruise ship? Have a story or tip to share? Email this reporter from a non-work address at htowey@insider.com