The Green Party leader says he apologised for reposting a tweet criticising the officers' response because it was "not the appropriate forum".
Avon and Somerset Police said the incident was not believed to be terrorism related.
The state visit to the US draws a positive response after what was a difficult diplomatic challenge.
Ministers hope move would help avoid last-minute flight cancellations for passengers this summer over Middle East fuel supplies.
The boat, carrying 82 people, ran aground on a beach in northern France, says local official.