Lifting lugs provide a dedicated, rated point to attach rigging for hoisting. They are attached to a workpiece—often welded or bolted onto surfaces like shell plates or sheet metal—to give slings, shackles, or chains a secure place to grab and lift the part safely. This makes the lifting process controlled and reduces the risk of damage or failure during hoisting. The other options describe items that serve entirely different purposes—decorative handles, general fastening hardware for bolts, or tools for cutting sheet metal—so they don’t match the role of a lifting point used in rigging.

The perimeter of a rectangle is twice the sum of its length and width. Add the dimensions while keeping consistent units: 8 ft 6 in plus 4 ft 7 in gives 12 ft and 13 inches. Since 13 inches equals 1 foot 1 inch, the total becomes 13 ft 1 in. Doubling this, the perimeter is 26 ft 2 in.

In boiler construction, joints must be strong and leak-tight to handle high pressure and heat. Welding is the main method used because it creates a continuous metal bond across joints, giving uniform strength and eliminating gaps through which steam could leak. This approach also provides smoother interior surfaces and better stress distribution, which are crucial for pressure vessels and reliability under demanding conditions. Bolts and threaded fasteners come into play mainly where parts must be removable or reworked, such as flanges, gaskets, manways, or access doors. Riveting was common in older boilers, but modern practice has largely moved away from rivets in favor of welding for the shell and major joints. So, the most common approach for the boiler shell and major joints is welding, with bolts and threaded fasteners used to connect removable components rather than form the primary joint.

Plate dogs are tools used to grip and position flat plates during boiler plate assembly. They provide a secure clamping point on a flat shell plate so you can lift the plate into position or hold it steady while it’s being aligned, riveted, or bolted. This makes handling large, heavy plates safer and more precise. They aren’t used to seal edges, drill holes, or measure thickness, since those tasks require other tools.