THE driver of a motorboat towing Wagga water-skiier Joe Howard when Mr Howard crashed into a tree and suffered fatal injuries breached a number of local rules or the law leading up to the tragedy, it was claimed in court on Friday.

Prosecutor Brendan Queenan argued the case in Wagga Local Court for the guilt of 51-year-old Lockhart man Robert Richards who is charged with operating a recreational vessel negligently causing death.

Richards has pleaded not guilty to the charge as well as two back-up charges.

His counsel, Mark Dennis, put to magistrate Michael Antrum that he could not exclude the possibility Richards as master of the vessel had done nothing wrong, and in the end - with respect to Mr Howard - it could have been a failure on his part that led to the accident.

Mr Howard, 34, died at the Colombo Creek Ski Club Reserve on February 22 last year.

Seconds after being towed around an island near the take-off area the father of three and general manager of Rundles Auctions crashed into a tree on the edge of the creek bank.

The court heard on Thursday that leading up to the crash, Mr Howard was on his back or backside, which is standard for barefoot water-skiiers before they stand up.

He was at the end of an 18m tow rope in a water channel 50 metres wide.

In his closing submission on Friday, Mr Queenan put to the court that Richards was going around the island in a clockwise direction, contrary to a local rule to go anti-clockwise.

He said Richards had no observer in the boat to watch over Mr Howard and that Richards was not a safe distance from the bank.

Mr Queenan put to the magistrate that Richards was going too fast - about 60km/h to 65km/h when local rules had a 40km/h limit in the area.

He said the prosecution essentially said Richards was an experienced operator with expectations of a high standard of care and when all these failings were put together he was negligent.

He said Richards had gone into the corner too fast with Mr Howard on the outside of the boat's wake in a whip motion.

In his submission, Mr Dennis said the way Richards went around the island was the safer route and was an accepted practice in the area on a quiet day, which it was.

He said he doubted an observer on the boat could have done anything.

The speed Richards was doing was no more than what was required for a barefoot water-skiier to get to his feet, Mr Dennis said.

Mr Dennis said evidence of witnesses was that Richards was in the middle of the channel, and there can be no safer place in regard to distance from either bank.

The court heard that while the benchmark requirement was for skiiers to be at least 30m from a bank there were few rivers that met that requirement, even the Murray River.

Mr Dennis said being outside the wake was a matter of risk management for the skiier.

Mr Antrum reserved his judgment until September 5, saying he needed to consider the evidence and submissions.

He said it was a very difficult case and he thanked Mr Queenan and Mr Dennis for the way they conducted their cases and showed respect for Mr Howard.