A man is fighting for life after his head was impaled by a "sizeable" piece of wood during a boat crash on the Gold Coast.
Police said the 47-year-old was with two other men in a dinghy that careered into an unoccupied yacht anchored at the Esplanade on Sunday.
During the collision, a large splinter of wood penetrated the man's head behind his right eye.
Acting Superintendent Scott Knowles said the three men sought help for their friend at a nearby dock.
"There was an off duty doctor there at the time and the men had attempted, or were talking about, trying to remove the impaling piece of wood from the man's head," he told reporters on Monday.
"Fortunately, this doctor was there to intervene."
The man was rushed to Gold Coast University with life-threatening injuries where he remains in a critical condition.
"We might be in a different situation if those men had removed that splinter," he said.
Supt Knowles said the man would undergo surgery to remove the "sizeable" splinter.
"It's a little bigger than a splinter ... It was sizeable enough that he requires surgery to actually remove it and the hospital has some serious concerns about the process of doing this," he said.
The two other men - aged 41 and 56 - are helping police.
Supt Knowles said speed, drugs and alcohol would form part of the investigation into what caused the crash as the dinghy was travelling between Sovereign Island and Paradise Point.
He said the damage to the yacht was not enough to cause it to sink but was "quite significant".
"There's certainly some damage there so the strike must have been at a reasonable rate of speed," Supt Knowles said.
Police appealed for witnesses or anyone with footage to come forward.