'Boatswain' was a British and Palestinian Jewish undertaking intended to destroy the Vichy French oil installations in the port of Tripoli, the second city of Vichy French-controlled Lebanon (18 May 1941).

This was the first operational mission carried out by the Palmach as part of the co-operation between the Yishuv (Jewish population in the British mandated territory of Palestine) and the British in World War II. The Palmach was established as the Yishuv’s elite combat force by the high command of the Haganah (Jewish paramilitary organisation in Palestine) on 14 May 1941 with the objects of protecting the Yishuv against attacks by Arabs in the event of a British retreat from Palestine, and the defence of Palestine against any invasion by the Axis powers or their allies. Under the command of Yitzhak Sadeh, the Palmach initially comprised about 100 men.

Early in the summer of 1941 the British agreed to joint operations against the Vichy French in Lebanon and Syria. The first action to be planned was a sabotage mission against the oil installations of Tripoli as it was feared that these could provide the Germans with fuel should they seek to intervene further in the Middle East. The oil facilities, which included a refinery, lay in an area strongly held by Senegalese troops of the Vichy French army.

The 'Boatswain' plan was based on the use of a motor launch for the delivery and subsequent extraction of 23 Palmach commandos under the command of Lieutenant Tsvi Spector. Embarking at Haifa, this party was to approach Tripoli from the sea. On arrival, three of the Palmach commandos were to remain aboard while the others landed to sabotage the oil facilities. Also present would be a British observer, Major Sir Anthony Palmer.

Practice runs in Caesarea proved the general feasibility of the plan, and on the night of 18 May Palmer and the Palmach unit boarded a police launch, named Sea Lion, and departed Haifa. The launch and its men were never seen again, possibly as a result of the detonation of the explosive charges with which the party was equipped, or possibly as a result of a Vichy French interception and destruction of the launch as it approached Tripoli.