Have you ever seen pins on a cruise ship? For as long as I remember, the huge cruise ships in the Nordic area used to have really good arcades onboard. Always the latest vids and pins and naturally a full selection of gambling machines.
A lot of people go, "wait, isn't it impossible to play with the ship rocking and stuff?" and the answer is no, the ships are so big and well stabilised the sea is really not an issue, but the games were still bolted onto the deck!
But with often rowdy audience, the games had some noticeable mods done to them. The coin door had a beefy steel plate with more reinforcements inside.
They also had a credit board they used on simpler games to set the game price. I guess they just had those in every game.
The playfield usually plastic upper trim was now stainless steel and the bottom speaker had a protector on it too.
They had a keyed power switch so they could be turned off if the ship docked somewhere the operator couldn't legally do business in.