Six tools for a boat with no signal. Each one installs as its own icon and works with the antenna down.
Putting them on the home screen
Each tool is a separate page, so each one gets its own icon. Open a tool, then in Safari use Share → Add to Home Screen. Repeat per tool. There is no installer and nothing to update by hand — a tool reloads itself when its page changes.
What offline actually means here
The first time you open a tool it caches itself. After that it runs with no network at all, including in airplane mode and out of range. That is the whole point, so it is worth proving once at the dock rather than discovering it at sea: open every screen, turn the network off, and relaunch from the icon.