Sam Beltz, Blair Tunevitsch and Tom Gibson are already locked in with Ali Foot in pole position to take the final spot and only too aware of the history that would make.

``The lightweight four has always had a big Tasmanian involvement, we've dominated it since the Atlanta Olympics, but we've never had an all-Tasmanian crew and that would be exceptional,'' Foot said yesterday.

``I've rowed a pair with every guy in that boat, with Blair and Beltzy we've laid down some strong markers and come close to a world record, while it was Tom who originally taught me to row sweep, so I'm really hoping we can get together because I'm sure it would be a really exciting crew.

``In training our speed has been exceptional, we've just got to string it together this weekend over two kilometres.''

Hobart duo Beltz, of Lindisfarne, and Gibson, of Huon, made up an all-Tasmanian crew when they contested the lightweight men's double sculls at the Beijing Olympics, but having been reserves for the four which finished fourth at London in 2012, Tamar cousins Foot and Tunevitsch have been highly motivated to step up.

Foot had been among the top two lightweights all season before a bout of gastro prevented him competing in the all-important national trials. He now finds himself in a head-to-head battle with his Hobart housemate Nick Silcox for the final spot in the four.

Whoever misses out after this weekend's trials will join Silcox's fellow Queenslander Darryn Purcell in the non-Olympic coxless pair.

``It's a bit funny that Nick and I live together, but have been racing each other all year and this weekend will be no different,'' said Foot, who turns 26 next month.

``The gastro knocked me out for four days and it's taken a while to get my fitness back. I've been working hard to build up my strength, I'm now at the right power-to-weight ratio and this is an extremely important weekend for me.

``Hopefully we can lay down a really good performance and get things on track ahead of the World Cup. We've got the cattle, we've just got to put it together on the water.''

The showdown will take place on the familiar waters of Lake Barrington where a training camp is being staged by national head coach and triple Olympic champion Drew Ginn.

The finalised lightweight crews, both coached by Tasmanian Institute of Sport head coach Brett Crow, will then contest a World Cup in Lucerne, Switzerland, ahead of the world championships in Amsterdam where the four will seek to repeat the 2011 gold medal won by the London Olympic crew of Beltz, Anthony Edwards, Ben Cureton and Todd Skipworth.

``To make that next step is what I'm aiming for and been training towards since 2010,'' added Foot, who has been teaching part-time at Fahan School. 

``It's been four years of focusing to get in that boat, and then obviously you're well-placed for the next Olympics and we can keep building leading in to Rio.''

The national camp will also involve the men's heavyweight eight and four squads, which includes 23-year-old Melbourne-based former Tamar rower George Ellis.

Tasmania has 19 national representatives plus three coaches training for the world championships, John Dreissen (men's eight) and Paul Newbon (women's under-23 lightweight double) joining Crow.

Meanwhile, under-21 national representative Oli Cook is training in Launceston for a national series against New Zealand.