The Erskine Park resident, 22, will take part in the Splash for Cash swimathon at Sydney Olympic Park Aquatic Centre on April 11.

The annual event raises much-needed funds for the Royal Institute for Deaf and Blind Children, which celebrates its 150th anniversary this year.

The charity provides assistance to almost 900 children across Australia with a hearing and/or vision impairment.

That includes 57 children in the Blacktown area.

Hennessy will take part in the swimathon for the fourth time.

She was inspired by her grandmother, Patricia Hennessy, a long-time volunteer with the Blacktown City Lantern Club which has raised more than $550,000 for the institute since 1972.

Hennessy hopes to better the impressive 116 laps (5.8 kilometres) she swam last year.

She swum at a national level before giving up the sport a few years ago to focus on her career.

Now in its 27th year, Splash for Cash is open to swimmers of all ages and abilities.

Participants swim as individuals or as part of a team and obtain sponsorship either for each lap they swim or just for taking part.

The top three registered individuals and teams who raise the most money will share in $7000 worth of Qantas vouchers.

Registered participants can take part on an alternative day or at a different location.

To register or support Hennessy's efforts, call Kaye Bailey on 98720329.

FOR MORE INFORMATIONsplashforcash.com.au