Mark,

You can add a rule for "account.analytic.line" with domain [('create_uid', '=', user.id)]

Or

Override the action for "Timesheet Activities" and add a filter(domain, same as above) to that action.

Regards

Thanks, with that rule all of the entries are still visible for other users and also the weekly view is not available anymore. So it's not what I'm looking for.

Only the users own submissions should be visible and editable.