The Grillet was one of three boats that accompanied Hitler's yacht the Aviso Grille, which was seized by the Royal Navy after World War Two.
The yacht spent part of its time in Hartlepool before ending up being scrapped in the US.
Owner Ron Cadman hopes a missing binnacle and compass are still in Hartlepool.
He told BBC Tees: "It's the original brass binnacle with the compass inside. In June 2014 it appeared in an auction, I didn't know until early this year, the auction house said the person who put it in was from Hartlepool, hopefully I can get it back for the boat."
Mr Cadman, who is currently in the United Arab Emirates, said he is trying to find a Hartlepool man called David Dixon who entered it into the auction in Taunton. The lot was returned to him after it failed to sell.
The Aviso Grille was one of the biggest yachts in the world and the smaller motor boats were needed to ferry people into harbour.
At 36ft (11m) long the Grillet was the largest of the three motor boats.
Adolf Hitler planned to use the Grillet to transport him up the Thames to Windsor Castle, which was to be his home in the event of a successful invasion.
Mr Cadman said it is not the boat's association with Hitler that interests him.
He said: "At the end of the day it's an historic boat, regardless of Hitler.
"The boat itself is a 1934 German naval pinnace, there are very few of them surviving, it is just an interesting boat from that period."
After the war the Grillet was used for many years as a rescue launch by the Hartlepool Sailing Club before being sold several times to owners around the world.
It is currently out of the water but Mr Cadman said he is hoping to restore it to its original condition.
The owner of a motor boat which once belonged to Adolf Hitler is hoping to find a missing part in Hartlepool.