All I have is:

/summon Minecraft: Boat ~ ~ ~ {NoGravity:1,CustomName:Name,CustomNameVisible:1}

How do I add ice under it every second?

1

1 Answer

First of all the correct format is:

/summon minecraft:boat ~ ~ ~ {NoGravity:1,CustomName:Name,CustomNameVisible:1}

Although I am not sure why you would want it to not have gravity. That results in the boat floating and making the ice useless. You might want to remove that.

Then you can have the following command run every tick:

/execute at @a run execute at @e[type=boat,distance=..1] run fill ~-12 ~-1 ~-12 ~12 ~-1 ~12 ice

This makes it only summon ice under boats the player is within one block of.

NOTE: since your goal is clearly to have ice to drift around on, this likely will not work. Ice causes boats to go faster, and they quickly outrun the radius of the fill command causing them to fall off the ice area. Thats why I had to make it so big.