OK, let's get something straight. I wasn't actually on the 240ft, six-deck mega yacht Axioma at the same time as Kendall who chartered it in Monoco last May for her 19th birthday and invited Gigi, Bella and Hailey Baldwin and Lewis Hamilton to share the party.

But as I explored the ship eight months later – from the below-deck cinema to the upper-deck Jacuzzi  – en route from the Caribbean island of St Martin to St Barths via Anguilla, I convinced myself that I could hear the ghosts of Kendall and Gigi giggling by the pool (yep, there's a pool on a giant yacht in the middle of the sea, because… YOLO). Then I realised it was a seagull and ordered another pina colada.

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Rather than bore you with the story of quite WHY and HOW I ended up on a mega yacht owned by a Russian billionaire which charters for over £420k a week (and that's not including food, drinks and fuel), I'm going to focus on the insight I got into keeping up with Kendall's krazy world. Because now I've sat on the same jet-ski and shared the same cabin as the super model, I'm practically one of the family, right? 

1. You are only ever a moment away from Mariah Carey

Moored off the shores of Anguilla we pulled up alongside an equally enormous but not half as pretty vessel owned by businessman James Packer. I was quite astonished to be reliably informed that it contained one Mariah Carey. I circled her ship a few times on a jet ski hoping for a glimpse, but alas MC was too busy at the butterfly sanctuary.

2. To get anywhere near Axioma you (or someone who loves you very much) needs to be outrageously rich

The amount it costs to charter (boat speak for 'rent') Axioma for a week could buy you a lovely two-bedroom flat with a garden in north-east London. Buying the boat - so that all 240ft of it BELONGS TO YOU (*insert evil laugh*) will set you back around £65 million. How Kendall scraped together the cash for her maiden charter voyage is a mystery.

3. Kendall could stay out as late as she liked on shore

Two handsome deck hands will have driven her by speedboat to the nearest island whenever she liked. If it happens to be 11pm when she set off for a local bar to see a reggae band and then stayed there drinking rum and dancing to Calypso Adele covers until 3am (as I did), the handsome deckhands will still be waiting for her when she stumbled out. They will deliver her safely back to the mothership where she could have chosen to wake up the chef and demand he makes her a pepperoni pizza... He will.

4. She could order any thing at any time

A hamburger and fries for breakfast, a magician, a harp, a karaoke machine, the tiny screw you need to fix your sunglasses... On Axioma you need only think about something you want, or need, and one of the 20 ruddy-faced deckhands will pop up in front of you with it on a silver platter. The staff would not divulge the exact nature of Kendall’s requests but, what would any 18-year-old mega celebrity want? Someone on hand to take full-length pictures of her in a bikini, obviously.  

5. She didn't need to bring her own sun cream

Scattered around all five open air decks are big baskets overflowing with free Clarins sun protection (a small bottle of which normally costs £32)

6. She didn’t need to swim to enjoy the sea

Ever heard of a ‘sea bob’? Me neither. But I am now intimately acquainted with this £7,000 underwater scooter, which you grab onto from either side to be zoomed across the waves. Kendall and the gang surely spent some time frolicking around the high seas on said ‘bob’ – so much more efficient than swimming, plus if you go fast enough it pulls your bikini down. Oops - sorry boys ;-).

7. You too can recreate Kendall's most liked Instagram photo ever

Put on something white . Lie on this specific patch of carpet in the hallway that leads to the bedroom cabins. Lay your long dark hair out around your head. Make heart shapes out of strands of hair. Take photo. Post photo to Instagram. Watch the 2.6m ‘likes’ flood in…

8. Kendall was never bored

She could have watched any film ever made at any time. There’s an 8-seat cinema with a 3D screen. Of course it’s 3D – you’re on a super yacht ffs. There’s also a gym, though Kendall, Gigi and Hailey will have struggled to keep their hot bods in shape as running on a treadmill on a moving ship is not easy. Thank goodness there’s a lift in the centre of the boat to whisk you between entertainment options.

9. She stayed up way past her bedtime

As long as you are awake, a member or three of crew are up to cater for your every whim. Cocktails in the Jacuzzi at midnight? Sure! A top deck sunrise dance party? Absolutely! You want rare steaks from that place in St Barths at 4am – someone will just hop on the speed boat and fetch them for you. If Kendall and krew didn’t throw a hell of a party on Axioma they must be dead inside.

10. Kendall and Gigi were seriously brave to jump off the ship from the second to top deck

It’s really high and really scary.

11. Permission to act like seven-year-olds, granted!

If you ask nicely which I’m sure KJ did, the staff will set up an inflatable slide from the middle deck into the sea  (about 40ft). SO FUN. She would probably have asked them to squeeze washing up liquid on to the slide (as we did) for a smoother, faster ride. If there were prizes for the most elegant splash, we’re sure Kendall would have won.

12. Lie in in luxury

How do you imagine bedrooms on a boat? Pokey? Bunk beds? Dubious washing facilities? Oh how wrong you are!  The yacht can sleep 12 guests in 6 staterooms, including a master suite, 3 VIP staterooms, and 2 twin cabins. The interiors are all blue marble and lacquered oak with gold details. Beds are large and sumptuous, there are rainshowers, hot tubs and walk-in wardrobes. And all, obviously, have sea views. We can’t help wondering who Lewis Hamilton bunked with.

13. Dinner on board is EVERYTHING

There’s a chief steward called Susie who catered to Kendall et al but politely refused to tell me any juicy details. For every dinner served on the large round table on the middle deck ‘chief stew Susie’ creates a bespoke table arrangement around a theme. I hope Kendall enjoyed ‘Carribean (see below)’, ‘English Country Garden’ and ‘under the sea’ dinners as much as I did. The food is cooked by just two chefs who also have to make the crew’s meals each day in a small kitchen below deck. Kendall will have been served the likes of grilled fish, Wagyu beef , Ottolenghi-style Moroccan salads and freshly baked cakes.

14. Kendall could have got her haircut at sea

But she didn’t or the internet might have broken. There is a hairdresser on hand and also a masseuse and a yoga teacher. And a beauty treatment room with a hamman steam room. Oh, now you’re asking about carbon footprint? It’s far to late for that.

15. Don't even think about unpacking

Kendall Jenner doesn’t unpack her own bags, and now neither do I. Ah the joy of returning to ones cabin to find all one’s beautiful off-runway outfits (or in my case stripy ‘going on a boat’ Tshirts) perfectly hanging in one’s closet.

16. Be prepared for a Harry Potter theme night

Someone from the engine room is allowed above deck to dress as a wizard and make guests pick their ‘house’ (which later corresponds with a seating plan) from an up turned witches hat. The table is bedecked with the entire contents of Harry Potter World and dinner is accompanied by the film’s rousing soundtrack. Incongruous? Random? Plain mad? Yes, yes, yes but after 3 days at sea drinking prosecco for breakfast it all just makes sense. Did chief stew Susie unleash her Harry Potter theme night on Kendall Jenner, Lewis Hamilton and Gigi Hadid? I really hope so. I wonder what ‘house’ they ended up in. Probably Hufflepuff.

17. High heels are banned - even for super models

Manolos might as well walk the plank because it's bare foot only onboard. Fine for Kendall who is tall like her dad Caitlyn Jenner at 5'10... but her dimutive sisters might have struggled. Maybe THAT'S why they weren't invited.

If you would like to charter a super yacht just like Kendall Jenner visit ypigroup.com

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