How To Percussion Test A Boat Propeller For Dezincification скачать в хорошем качестве

How To Percussion Test A Boat Propeller For Dezincification

Boat propellers have a tough life and get more than their fair share of bumps and knocks so they need to be in good condition. Many propellers sold as being ‘bronze’ (an alloy of copper and tin) are actually ‘brass’ (an alloy of copper and zinc), Manganese Bronze being the most common example with up to 40% zinc. As part of a condition survey of a late 1970s Moody 30 sailing yacht, marine surveyor David Pestridge explains how percussion testing the propeller can help develop a picture of the condition of the material and how a marine surveyor might write their findings for their client. Percussion testing in marine surveying is the black art of striking a surface (hull, deck, bulkhead, propeller etc) with a hammer with the aim of identifying defects in the structure. It is a non-destructive testing technique that takes skill, practice and experience to execute well. The core principle requires choosing an appropriate hammer, striking the structure in the right places, with the right amount of force and interpreting the results gained. Percussion testing is equally applicable to wood, metal, composite and laminate structures and the procedure varies according to the nature and thickness of the structure being tested and the defects that are likely to be present. If this video was useful for you and you want to get more content like this, head over to the Boat Chat newsletter and subscribe for free for regular updates on key maritime news stories, surveying tips, tool and book reviews. It’s a great read for boat owners, surveyors and anyone else interested in small craft. https://boatchat.uk