Half of my AC panel is out

I don’t understand why all the opposition to running off a single 30 amp 110v outlet using an appropriate 50 amp to 30 amp adapter? Yes, he will need to be conservative with loads. Battery chargers should mostly be on float. You could run a refer and a few other small draw items, lights, etc. I also don’t understand why the adapter will only power one leg? Is there something unique about Tiara panels? A 30 amp adapter should feed 110 v to both legs but, of course, you only have 30 amps total. I certainly wouldn’t suggest running this set up anywhere near 30 amps continuously but if it is just for storage what’s the issue?
I’ve run mine on a 30 amp when traveling to marinas that only have them and it worked for me.

Your going to tell him it's O K? To take two 50A-120Vac (120-240V-50A plug) leads and put them on a single 30A-120Vac plug.
What are you going to say after the fire?
I'm not going to tell him it's O K.

FWIW, neither do I, as I already said.
Imho, there is ZERO risk on the boat side, including the shore power cord, which being designed for 50A can obviously handle a constant 30A load, and then some.
The only Worthy vessel's bit which is at risk is the 50A/30A adaptor, whose 30A male plug might fry if overloaded (I am assuming that the short bit of cable connecting the male and female plug is sized for 50A), but only if the pedestal breaker wouldn't work as it should.
Which is the only real risk, and this is essentially a marina's problem - though I did suggest also to check with them that the pedestal is fitted with an appropriate (and working, obviously) breaker.

It is safe as long as the breaker on the pedestal works. Going to be a major PITA managing the loads though but if you don’t intend on staying aboard at all it will be ok.

So you’re saying regardless if loads are kept low there will be a fire?
No.
However, I have seen the aftermath of fires caused by the owner modifying their shore power equipment.
I recall the insurance investigators call it their Hot Potato..

I do believe this can be done safely with reasonable load monitoring.
Rite. Let see what we can turn on before the breaker trips, POP.
Lets see what else we can turn on before the breaker trips, POP.
Lets see what else we can turn on before the breaker trips, BUUUUZZ, Uh Oh..

I have to share another smile .
Going to purchase a near $400k boat.
Wants somebody to tell him a Jerry-rigged electric connect is O K.
Going to heat up some wires and trip breakers as a norm.
Can't afford a dock with proper electric service or update the dock they want to use?

All your points above can be said the same regardless if on 30 amp or 50 amp. If someone is going to operate their boat that way they will have issues regardless. I also don’t consider buying an appropriate adapter that you can get at just about any Marine store “Jerry- rigging”. Further, how can an insurance company deny a claim just because someone uses an adapter? These meet codes.
Lastly, I don’t know of many marinas where you can simply upgrade to 50 amp for your stall unless it is a private slip. Personally, I would find a slip that has 50 amps. But that doesn’t mean he can’t safely operate on 30 amps if this is all he can find or all that is available where he wants to be.

CR, you are making me wonder if there's something I'm missing due to a different US practice compared to what I'm used to.
On this side of the pond, boaters have ZERO responsibility on how appropriately the dockside equipment is arranged and kept in good order. Is it different in the US maybe, and anyone using a pedestal becomes automatically responsible also for anything that can happen to the pedestal itself and to its internal wiring and breakers (and also water supply, for that matter)?

If yes, I understand your concerns, because by drawing more than 30A (AND if the pedestal doesn't have a correctly sized and properly functioning breaker), WV could potentially set the pedestal on fire.
But I would find such responsibility weird to say the least.
What if the pedestal would have been wired with tiny 20 AWG wires, behind the 30A socket?
Anyone drawing MUCH less than 30A would immediately melt the wires inside it!

Besides, there would be absolutely no risk for the boat when using a 30A pedestal to feed a 50A onboard connection, even if the pedestal breaker wouldn't trip off (as it should) as soon as the load exceeds 30A.
In such worst case scenario, of course there would be potential troubles, but strictly on dockside, not onboard.

There is no 120-30A to 120/240-50A adapter.
There is a reason for this.

YOU tell him it is safe and O K and I will stop typing here.

I think it may be a private dock. I'm sure some deal can be made on upgrading the service.

dockside equipment is arranged and kept in good order

Single 30A 120Vac outlet. That's it. That belongs to the dock.

The cord, adapters, and the boat, belong to the boat and owner.
Their safe operation is the owners responsibility.
If he abused that 30A outlet like constant tripping the breaker or melting the receptacle, that may be on the owner also.

I have tried to tell the owner (soon to be owner) any non standard hook up must be considered an emergency and temporary setup. Not to be walked away from and still a hazard.

After one of you kids tell him it is O K, I'll be done typing here.

So, you got an O K from the factory (amazing).
Please be careful.
Would like to hear about your new boat.

Update to my comment.
There is a split 120Vac- 30A to a single 120/240-50A adapter.
It uses dual (that means 2) 120-30A inputs and applies either 2 x 120Vac legs to the 120/240Vac ships or if continuous phased (still single phased), 240Vac and/or both.
It does not combine a single 120Vac-30A input to a 120/240-50A ships connect. Just one (120Vac-30A) leg at a time.
In using this adapter, a single input leg will be used while the other is hanging in the wind.
Hopefully one leg will include the refer and battery chargers.
I am still highly cautious of this installation.
Please see post #46.

But the Factory said it was O K.

Thanks for the youth attribution, but I have a funny feeling that you might not win a contest about who has more grey hairs.
Regardless, if you are so convinced that what some "kid" is suggesting is so dangerous, don't you think it would be even more childish to give up typing here and stop warning anyone else against that?

That aside, ref. the 30A to 50A adapter not existing, isn't this the thing we have been debating so far?
https://www.ebay.com/itm/203502849372
With advance apologies if I missed something, but while I'm confident that the principles of electricity are the same, the type of plugs/sockets I'm familar with are different around here.

That is a 120V-30 to 120V-50.
This will require 120V-30 to 120/240v-50 connect.

Well, You found one.
Scary.
I was incorrect in my statement that they were not made.
Good luck.

So, what? Following your reasoning that the 30A breaker in the pedestal might be faulty, you could still melt the 30A plug or the wires upstream of it by pulling 50A through the adapter - regardless of voltage.