13 WHILE TACKIG
After a boat passes head to wind, she shall keep clear of other boats until she is on a close-hauled course. During that time rules 10, 11 and 12 do not apply. If two boats are subject to this rule at the same time, the one on the other’s port side or the one astern shall keep clear.
15 ACQUIRIG RIGHT OF WAY
When a boat acquires right of way, she shall initially give the other boat room to keep clear, unless she acquires right of way because of the other boat’s actions
Google is your friend.... "ISAF rules"
You said... the boat was moving slowly.... well beyond ... on close hauled course... AND you had opportunity to stay clear...
