On 31 August 1739 he was promoted to be lieutenant of HMS Tilbury, one of the ships which went out to the West Indies with Sir Chaloner Ogle, and took part in the unsuccessful attack on Cartagena in 1741.

In 1742 he was first lieutenant of her when, on 21 September, she was set on fire in a drunken squabble between a marine and the purser's boy and burnt, with a large proportion of the ship's company.

In July he was moved by Moore into HMS Raisonnable, which was lost on a reef of rocks at Fort Royal off Martinique as she was standing in to engage a battery on 8 January 1762, when the island was attacked and reduced by Rear-Admiral Rodney.

[2] Peace had been declared between England and France, and Shuldham was ashore on half-pay until December 1766, when he was appointed to HMS Cornwall, the guardship at Plymouth.

At the general election in the following autumn he was returned to the House of Commons as member for Fowey, and on 29 September, was appointed commander-in-chief on the coast of North America from the river St. Lawrence to Cape Florida.

His body was transported back to England aboard HMS Colossus, which was also carrying many of the antique vases collected by Sir William Hamilton.

Colossus was wrecked in a gale on the Isles of Scilly, but while many of Sir William's vases were lost, Shuldham's body was recovered through 'heroic efforts'.

He had married Margaret Irene, widow of John Harcourt of Ankerwycke Park but left no issue, and thus the title became extinct.