HOW DO I KNOW WHERE A DECK STRONG POINT IS?
One of the most crucial parts of freight forwarding, whether it be a 1 tonne wooden box or an entire ship on a barge, is the correct and safe installation of seafastenings. Seafastenings can be welded blockers, chains, web lashings or wires – all of which require a connection to the vessel, to either the deck or the hold side.
However, how do you choose the right place to position these connections – all require welding and will be subject to some form of loading.
Welded blockers, as the name suggests, require welding to the deck, but chains, web lashings and wires all require d-rings or some other form of lashing eyes to secure to.
The primary objective when locating a securing point is to ensure that there is sufficient underdeck structure to support the loading, as if a securing point is welded on top of unsecured deck plate, there is a high risk of damaging the deck, or of the seafastening failing, or both!
Vessel decks have crossing underdeck frames which are ideal for positioning welded components above – these are shown on vessel’s Structural Arrangement Drawings or sometimes on the General Arrangement. The size, location, and quantity of these frames should be well understood before attending a loadout. Often it is the case that when onsite, the frames are not visible due to the deck plating, but if you are ever stuck, here is a simple overview of how best to find them:
1.Grab a hammer/ D-Ring/ any other solid object
2.Hit the deck while moving fore to aft (for transverse frames) or port to starboard (for longitudinal frames).
3. Listen closely and you will notice a distinct change in pitch of the hammer strikes
4.When you hear a hollow, dull noise, this is unsupported deck
5.If you hear a crisp, solid noise, you have found your underdeck structure
This method should be used to ensure that the seafastening is secured to the stronger points of the deck to ensure it may be utilised as designed.