A way around the power strip/surge protector problem is that many devices we use these days are USB charged. A USB charging bank has yet to be on the prohibited list (may only be a matter of time) If your device is USB charged, plug it into the USB bank instead. If you travel with a laptop, use the laptop's USB ports for charging your USB charged devices, and if you bring a laptop with you (I dont travel without my laptop, one of these years I'll do a fully unplugged from the outside world cruise but... not today LOL) you can bring a USB hub with you. I have a cheapy one I got at a trade show or was a promo or something, I forget where I got it from but its promo branded and has 4 USB ports on it. Slam that into the laptop and I've expanded 1 USB port to 4 USB ports and all of them can be used to charge stuff (camera, phone, gopro, tablet, nintendo DS, vape pen for designated location use only!). A small USB hub should cost under 5 bucks, you dont need bells and whistles. Same with a USB charging bank. You dont need one with power levels or charging statuses, or a massive bank. 4 ports should be more than enough for all of your charging needs. I also highly recommend bringing a USB adapter. I have one from my company (I have a ton of promo gadgets/gizmos for some reason) and it converts from standard USB to Lightning, mini USB, and like 5 others. That way the number of charging cables I need to bring are at a minimum. And I'm going to throw out this recommendation for cable management when travelling. I color code my individual charging cables with a small piece of colored tape. I keep a piece of paper with the colors for the cables and their associated device, and I check in the cables when packing to leave for the cruise, I check them out when I unpack, then check them back in when returning. I havent lost a charging cable yet when using this method. Helps around the home too when wanting to locate charging cables and all of them wind up looking alike and you wind up with a drawer full of a tangle of charging cables.
Also, dont be afraid to ask your cabin steward for a power strip once onboard. They have a limited number of power strips onboard (same with extension cords for CPAP users) If you're a CPAP user and need the extension cord, dont forget to fill out the special medical needs form! This will make sure your CPAP machine has the necessary water and extension cord.
Another way to get an extra plug out of your cabin, normally the older cabins have 1 US outlet and one .... not US outlet (sorry dont know what they're called). A travel adapter will allow you to use both the US and the non US outlets, maximizing what outlets you do have access to.
