Limits

Five screens,
and why.

Siparu has two limits you can meet in normal use: how many screens one boat seals to, and how many boats one account carries. The first follows from the encryption, because every report is sealed to a named list of keys. The second is how memberships are packaged. This page says what both are and what to do at the ceiling.

Last updated 1 September 2026

Five screens to a boat

Every report your boat sends is sealed to the keys of the screens on her list, and she carries five at most. A phone, a tablet, and a browser you have authorised each hold one of those five places. Five is enough for a household of devices, and short enough that you can read her list at a glance and vouch for every line on it. On a list that decides who can read your boat, that matters more than convenience.

When the list is full

Authorising a sixth screen is refused until a place is free. Freeing one takes a minute: open the boat's page, find Screens she seals to, and remove every line you cannot match to a device you hold. Each device prints its own line where its key lives: on a phone under Configuration, in This boat; in a browser at the foot of the boat page. Matching is by eye. A device you remove by mistake can be authorised again from any screen you still hold, so this is not a one-way door.

Two things are worth knowing before you remove a line. A screen that approved others takes them with it: they stop being read until a screen you still hold approves them again. And a new screen has to be approved by one that is already trusted, so if you remove the last screen you can reach, there is nobody left to approve anything and the way back is to pair again at the boat. Keep one screen you can open.

A screen whose browser data was cleared keeps its place on the list even though its key is gone. That line decodes nothing and belongs to nobody; remove it.

Boats to an account

Memberships are per boat: one membership watches one boat. For now a second boat needs its own account and its own membership; we would rather say so here than at the checkout. A fleet kept on one account is the exception, and it is arranged with us rather than at a checkout. On the boat's own network none of this applies: watching her aboard is free, for any number of boats, with no account at all.

Why both numbers stay small

Each screen is a key your boat trusts, so a short list is one you can read at a glance and vouch for. The boat count is packaging rather than cryptography, and we say so rather than dressing it up.