A parade and service was held at Blandford Camp where thousands of sailors from the Collingwood Battalion trained.
The Princess Royal attended the ceremony at the battalion's memorial.
The service commemorated those who died during the Third Battle of Krithia on the Turkish peninsula.
The battalion were almost totally destroyed during the eight-month campaign that was fought from 25 April 1915 to 9 January 1916.
More than 100,000 troops were killed and hundreds of thousands more were wounded.

Kevin Nunes was shot dead in September 2002 but five men jailed for his murder were freed on appeal.
Police and crime commissioner (PCC) Matthew Ellis said Mrs Sawyers had "no case to answer on misconduct or gross misconduct" relating to the case.
Ms Sawyers welcomed the decision.
Police believe Mr Nunes was a drug dealer who was shot in an execution-style killing in Pattingham after straying into another gang's territory.
But the men jailed for his murder were freed after it emerged concerns over the credibility of witnesses were not disclosed to the defence.
This prompted an investigation into the police's handling of a key witness and how disclosure was dealt with afterwards.
In January 2014, the Independent Police Complaints Commission (IPCC) said it would be submitting files to the Crown Prosecution Service (CPS) over the case for prosecuting senior officers, including Mrs Sawyers, for either attempting to pervert the course of justice or criminal misconduct.
However, the CPS said there was not enough evidence to proceed.
Publishing his response, Mr Ellis said while it was clear "something went wrong in relation to the investigation of the murder", Mrs Sawyers was not guilty of misconduct.
"My conclusion is that, whilst there were undoubtedly different actions and decisions that should have been taken at the time, the IPCC report does not produce evidence Mrs Sawyers has a case to answer in respect of misconduct or gross misconduct," he said.
"I have been clear, however, Jane Sawyers could have been more intrusive and sceptical about the actions of others at the time."
Mrs Sawyers said: "I welcome the determination the police and crime commissioner has reached."
The IPCC said it was waiting for all of the forces involved, including West Midlands Police, to respond to its report.

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Hill, 18, won the skeet title at the inaugural European Games in June and claimed victory at the World Cup final in Cyprus last month.
She is joined by world medallist Elena Allen and world record holder Tim Kneale.
"Every competition I enter, I go in trying to win," Hill told BBC Sport.
"To be named as an Olympian is an incredible honour and I'm getting more confident I'm able to win these competitions."
The 2013 BBC Young Sports Personality of the Year added: "Hopefully I can inspire some other youngsters to get into a sport of some sort - it really does make you so determined and focused on what you want to do in life."
At London 2012, Peter Wilson came away with the team's only medal - winning gold in the men's double trap, before announcing his retirement in 2014.
Four of the six shooters will go to Rio having previous Olympic Games experience.
Steve Scott, a World Cup gold medallist in Cyprus in October, came 12th at the 2008 Beijing Olympics and will join debutant Kneale in the double trap competition.
London Olympian Allen competes against Hill in the women's skeet competition, while 2014 Scottish Commonwealth silver medallist Jen McIntosh will line-up in the 50m 3 positions event.
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Two-time Olympian and world silver medallist Ed Ling is Britain's competitor in the men's trap.
"I'm absolutely over the moon, it's a huge honour," said Ling.
"I know what I'm going to expect going into this year and to obtain that Olympic medal is what we work for."
Team GB are sixth on the all-time Olympic Games shooting medal table with 44 - 13 gold, 15 silver and 16 bronze.
The number of Rio Olympic shooters in the squad may increase next year, as results at the European Championships in Hungary in February could unlock two additional berths.
Shooting is the third sport to have British athletes officially selected for Rio 2016, after eight sailors and four canoe slalom athletes were named earlier in the year.
The centenary of the Gallipoli campaign - one of the bloodiest of World War One - has been marked with a memorial in Dorset.
[NEXT_CONCEPT]
The temporary chief constable of Staffordshire Police, Jane Sawyers, will not face misconduct charges over the fatal shooting of an alleged drug dealer, the force's commissioner has said.
[NEXT_CONCEPT]
Amber Hill aims to become the first British woman to win Olympic shooting gold after being named in a six-strong Team GB squad for the Rio 2016 Games.