The blaze -- the biggest in the Hamilton area since the fatal coolstore explosion at Tamahere in 2007 -- started about 3pm at Tristram Marine in the Te Rapa Park industrial area, on the northern outskirts of the city.
Senior Station Officer Darryl Papesch told NPZA his thoughts turned to the Tamahere blaze "after the first explosion".
However, he put that out of his mind.
"We just treated it as a totally different incident," he said.
No one was in the yard at the time and no one was injured.
About 60 firefighters battled the blaze and were pleased to be able to save the about $8m of stock and equipment, including boats in the showroom.
Fire investigators were at the scene but the blaze was not believed to be suspicious.
