Just have a nameless portal in a safe place possibly close to spawn, if something happens just construct a nameless portal and you have access again. If you wish to build a portal in a permanent location then place down a 3rd portal at your base with the name, go through the nameless portal and give that the name so you have a 2 way link.

The nameless portal should only be used temporarily until you can fix the issue, it's also good for an emergency escape. Keep the materials for the portal in your boat and most islands should allow you to build one anyway you can get fine wood easily just by rolling a tree into the birch tree until it breaks, Surtling cores can be grabbed from the Swamp or Burial Chambers, the Swamp isn't difficult to navigate just avoid the night when wraiths come out.

To have many portals give them a code like an airstrip so Island 1 can be AA for example so your portal could be like "AABB Home", have the name on your map as well if you need to remember it should something happen.

If you want to cheat just swim until you get to an island you can use, go into another world to recover stamina.