I just bought 4 new mast head sheaves for my P30. I chose the 40-MH from Garhauer. I did have to ask them to make the ID 1/2" instead of 3/8". I suggest trying to take one of the old ones out to measure it and find a replacement similar in size. I am not sure my masthead is original to the boat which is why I cannot say with certainty to go with what I did.