Lifting Rib with crane/davit

[Charles9727]

Hello, I work with a Zodiac Nautic pro 6.5 for use in underwater research. At the facility I am using, it may become necessary to launch the boat using a crane.

My boat has 4 what a presume are lifting points. In the manual, under the lifting section, all it says is the boat can be equipped with forward and aft chain plates. They are a u bolt, with 3 screws, sandwiched with a small steel plate into fiber glass. Do you think they are safe to lift from?

[Pikey Dave]

Not quite sure where you are in the world, but normally in the UK & AFAIK most of Europe, any lifting point would be marked with the SWL/WLL of the point.
* SWL= Safe Working Load
WLL = Working Load Limit

[Charles9727]

Unfortunately, no such markings… It has been lifted from here before, but that doesn’t mean it should right?

[Pikey Dave]

Personally I would be wary. Without having a good look it’s hard to give sound advice. If it was mine I would be removing the plates, examining the substrate underneath for rot etc. if the fixing area is sound, I can’t see why the plates couldn’t be replaced & some bolts of known tensile strength used with appropriate lifting eyes. You might need to take advice from an engineer, or you could just over engineer it.

https://www.s3i.co.uk/wichard-folding-pad-eye.php

[beamishken]

Are you lifting just the boat or boat & crew? If its boat & crew they usually have single point lift points which are tested & certified if its boat only then less onerous. I worked on a DSV in Trinidad a few years ago & we were using an sr6 for transferring crew & assisting with the install of a super tanker offloading mooring bouy. The sr6 was kept on deck & deployed by the ships crane to the water when needed we had to board via a pilot ladder as the lifting points weren't certified. All that boat had was the transom D rings reversed to face inside the boat & two further D rings through the hull close to the bow with a stainless reinforcing plate on the outside of the hull. All connected to a 4 part bridal to a single master link .The boat took some hammer in the 9 weeks I was out there until the end of the job & it took some pretty hard snatch loads when hooking up to the crane with any sort of sea running. My daughter just bought an ex fish farm sr5.4 which had been lifted regularly too, her boat had the same, transom D rings reversed & an extra bow D ring added facing inward & a 3 point bridal