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Shipyard Blocks

Shipyard Blocks

Shipyard Blocks

We are investigating designing some ship block for marine an application. They will support vessels stored on a deck of a ship while it is underway. What codes govern the block designs, and what are load testing requirements?

RE: Shipyard Blocks

Are you referring to dunnage or block and tackle?

RE: Shipyard Blocks


RE: Shipyard Blocks

Most of the float on float off transports that I see in San Diego, use custom cradles that are welded to the deck by underwater welders, prior to the ship rising up out of the water. I think since you are deck cargo, you would be governed by Hague Visby rules.

You are judged not by what you know, but by what you can do.

RE: Shipyard Blocks

This is a very common calculation in naval architecture. Inputs to the calculation are the hull lines, a longitudinal weight distribution, a longitudinal strength report/drawing/analysis. This is when it is easiest to break the ship, by the way. The rough rule of thumb for ships is that 80% of the load is carried by the keel, the remaining 20% by the side blocks. For a cradle design, it is more even. The cradle suppurts should be girth-wise (a transverse slice) that occur at major subdivision bulkheads or at least on structural frames. You can calculate reaction forces using simple beam theory, with the section modulus coming from the longitudinal strength analysis. If you have GHS software, this is super easy using the Multi-Body module and ground forces.

Hope this helps and its not too late.

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