So - looking at your propane system, fuel system, electrical system, etc. if there's a practical way to bring it up to current standards, this would be a wise thing to do. It could save your boat, it could save your life.
This seems like a pretty common-sense approach to the issue of propane (and other) systems on a boat. I see this whole deal as two separate issues.
One is the "best-practices for boat systems" as described by the ABYC. These are (I assume) based on the continually growing data base of problems that can occur in the systems used on boats.
Seat belts didn't use to be used in passenger cars and trucks at all. As the database of accident details grew, it became more and more apparent that people being thrown around in or out of vehicles was a major contributor to serious injury or death. So the notion of seat belts caught on and they were at first optional or used only in certain models and then spread to all vehicles and eventually became mandatory in new vehicle designs.
I see the ABYC recommendations as being like that.
The second issue is one of common sense. Boats like the cabin cruiser we have in the PNW that was built in 1973 has a propane system for the galley that was deemed safe in 1973. As such, it
is safe. The locker is the molded fiberglass seat base on the port side of the flying bridge, and the two penetrations into the cabin below-- the propane line itself and the handle of the manual shutoff valve--- are sealed against propane intrusion. There is a vent in the seat base that leads overboard. And the entry into the box is a removable, lipped lid in the top of the box. The lid is NOT sealed with any kind of gasket and latch system as that was not considered necessary in 1973.
I think it is reasonable to expect today's more rigid recommendations/standards
not be applied to vessels that were designed and built prior to the establishment of these recommendations/standards. Depending on the difference between the original and recommended systems, compliance could involve a major effort and expense.
But..... I think it is smart on the part of a boat owner, regardless of the age of the boat, to look at the existing system, compare it to the current recommendations, and think about how the recommended configuration might improve the current system. Some things may not be practical to do given cost and effort considerations. And if the original system is objectively deemed to be safe under most or all conditions it will encounter, then leave it alone.
But if an original system is objectively deemed to pose potential safety issues---- for example a propane tank stored in a closed space containing electrical equipment like instruments, electronics, an electric air horn compressor, wiring for lights, etc.--- and the tank can be relocated to a more isolated enclosure without tearing the boat apart and incurring a high expense, then it would seem to be the smart decision to do that even if there is no legal requirement to do so.
The issue of surveyors and their reports and how insurance companies react is another matter. So far, the three surveyors we have used in the process of buying and then complying with insurance inspections have been very logical and practical. In the case of the initial buyer's survey, the surveyor wrote up everything he felt compromised the boat's operations, integrity, and safety. That's what we wanted him to do, and the things he determined needed fixing or changing we felt it was smart fix or change them regardless of the fact the insurance broker wanted them done, too.
In the case of the subsequent insurance surveys, the surveyors wrote up things they felt compromised the operation, integrity, or safety of the boat
and would also be of concern to an insurance company. Other less-critical items they found which they felt would not be of concern to an insurance company but that the surveyor felt we should know about and thus be able to correct per his recommendations, they wrote on a separate list that they gave to us.
In all cases with all three surveyors we felt that what they found and their recommendations were valid and would be smart--- and in some cases required--- to correct.
For example in the case of the boat's new-at-the-time replacement fuel tanks, which are made of stainless steel which in 1998 was not a fuel tank material recommended by the ABYC, the surveyor we'd hired to do our buyer's hull/systems survey (we hired a separate surveyor for the engines and generator) told us that the tank material was not recommended by the ABYC, explained in detail why the material was not recommended, but also said that if fabricated correctly, he'd seen stainless steel tanks in boats in his area go for years and years with no problems whatsoever. So he made sure we understood both sides of the issue and what we could to in the operation of the boat if we bought it to minimize the potential risk of stainless steel might pose, but he did not write it up in his formal survey report.
I think surveyors are like the people in every other profession. There will be good, bad, and indifferent ones. In my opinion, it is
on the owner or potential buyer to be smart in learning about judging and selecting a surveyor. It's no different than choosing a company to put a new roof on one's house, which we recently went through. It's not a matter of "you get what you pay for," it's a matter of "you get what your skills at research, evaluation, and judgment get you."
Ending up with a bad or incompetent surveyor is not on the surveyor. He (or she) is what he is. Ending up with a bad surveyor is on the person who vetted and then hired him.
At least that's my take on it.......