Steve Pateman believes his chances of a fourth consecutive Grand National Hurdle win depend on the weather.

The champion jumps jockey won the race on Black And Bent in 2011 and 2013 and Brungle Cry in 2012 and rides New Zealander Sea King.

Pateman, who is also going for his third successive Crisp Steeplechase win on Bashboy at Sandown on Sunday, says he has no doubt Sea King is the best stayer in the 3900m race but will need it as wet as possible to topple the favourite Gotta Take Care.

"I think Sea King is the best stayer in the race but Gotta Take Care will be mighty hard to beat," Pateman said.

"Hopefully the rain comes tomorrow and it's a good heavy track and that will really help."

Bashboy, Australian jumper of the year for the past two seasons, is the dominant favourite to win another Crisp Steeplechase (3900m) for Pateman and trainer Ciaron Maher.

He bounced back from a hiccup at Bendigo at his previous start to score a 10-length win in the Thackeray Steeplechase at Warrnambool on June 29, the same day Sea King won his Australian debut in the Lafferty Hurdle for new trainer Patrick Payne.

Pateman had pulled Bashboy out of the Mosstrooper Steeplechase two weeks earlier and a post-race veterinary examination detected an irregular heart rhythm.

"We were rapt with him at Warrnambool and he pulled up a treat," Pateman said.

"He should improve from that run and he's well-weighted against the other horses. So all being well, he will run really well.

"We always felt leading into his first jumps run (at Bendigo) this season that he was better than the last couple of years.

"A third-season chaser probably should be, although he's not getting any younger. He just seemed to be going better on the flat and simply better in every way. Warrnambool confirmed that was correct."

Bashboy carries 69kg under the set weights and penalties conditions of the Crisp which is 3kg less than he lumped to his commanding Warrnambool win.

Gotta Take Care has won the Galleywood Hurdle, Australian Hurdle and Brendan Drechsler Hurdle this season and has 71kg, 4kg more than Sea King.