The boat is a Delta and yes it is commercial spec. It had plastic tanks one of which split. Apparently plastic was acceptable then but not what they fit now.
F8 was very not my favourite but no cargo and only crew , we don't do passengers.
Going bang is even less of my favourite than a F8 ( we tend to try and can it at F6 )
I don't know why the surveyor didn't recommend anything else I'm afraid but I will ask him next time I see him.
The guys at Crosshouse replaced the deck in my Oceans cabin Rib. The standard of workmanship and service were first class. I'm sure they have pictures of the work carried out.
Highly recommend their services.
The latest is that the tank does not hold pressure and so it has failed. The job is now to remove the deck and replace the tank and refit the deck. We have invited quotes. Ribeye can do it but the lead-time for the tank is prohibitedly long as this would come from overseas. The decision now is what material to go for and who to supply and then who to award the work to. The job should take no more than two weeks, from the tank being available.
We had a company come and pressure test it - apparently, they disconnected pipes and vents, blocked them off and attempted to fill the tank with air. It would not pressurise.
I do believe tek tanks aren't so good with petrol tanks. I once went there to collect some stuff and they really didn't want to comment on petrol as their knowledge base is primarily diesel for fuel.
I bought one of their C series tanks which are CE rated for both petrol and diesel, lots of advice and they even made a small mod to it while I waited. The only issue I had was finding the place, satnav took me miles away.