Hi Beth - I know a tiny, little bit about English immigration to Chile! In the late 19th Century, the Chilean government had an immigration scheme to attract settlers from Western Europe (primarily Germany, Italy and England). They offered land in exchange for a commitment of labour of up to six years. At that time, the government and military were trying to establish the existing national boundaries of the country and pinch a bit more from their neighbours, particularly Bolivia to the north. They saw the settlers as a quick way to populate these areas and establish them as part of Chile. I am in Canada and I think the scheme was much like the one operated by the Canadian government in the early 20th Century (we were trying to keep the Americans from fulfilling Manifest Destiny!). My great-grandfather emigrated from Portsmouth to Chile with his family in 1890 and when that didn't work out, they moved to Canada ten years later. My great-uncle wrote his memoirs which included some fantastic tales of their life in Chile - including the time my granddad burned their house down!
Chile also had a growing mining industry at this time and many western Europeans emigrated to work and or manage the mines. The northern port of Antofagasta (which is just south of your IGI record of Tocopilla) was and I think still is a major shipping port to move the ore out of Chile and abroad. The link to the seaman could indicate he worked on a ship that called at one of these ports.
Now the last link I have relates to the gold rush in California and British Columbia. Before the Panama Canal was opened, ships travelled from Europe with a stop in Brazil, then round the Cape with another stop in Chile (Valparaiso was another main port), then up the West Coast to San Francisco and maybe even further to Victoria, BC. Many gold seekers (like my great-great-grandfather) ran out of money along the way. He managed to make it to San Francisco but many never made it that far. This would have been a bit earlier than your records, say 1850 - 1860 so I'm not sure it applies to your current research.
Well, that is my 30 second history lesson! I am sure others know much more about this than I do but maybe it will help to start you off.
Good luck,
Lynwen