Yes, you need a survey, whether an insurance company requires it or not.
The only time I would not recommend a pre-purchase survey is if:
a) You are a qualified SAMS certified surveyor.
b) You are highly knowledgeable in ABYC standards and sound boat building practices.
c) You are buying a project boat that will be completely stripped and outfitted after you learn b).
Way too many people look at a survey as an unnecessary expense. Way too many people are not as smart and knowledgable as they think they are. A survey provides you some protections from:
a) bad building practice by the original manufacturer.
b) changes in safety standards.
c) wear and tear.
d) poor DPO (damned previous owner) modifications.
I start my marine electrical seminars with,
Question 1: "How many have performed electrical modifications to their boat?"
(At least 50% of the audience raises their hand.)
Question 2: "How many believe that was performed properly and safely?"
(That same 50% continue to hold their hand up.)
Question 3: "When can we book an electrical inspection on your boat; no issues it's free, but on the finding of at least one safety issue, it's $200?" Only 1 or 2 book an inspection.
More interested in saving $200 than finding a significant safety issue on their boat.
Truly a fool's savings.
Get a survey, your boat, life, and crew may be saved for the sake of a few hundred dollars.
In practice, almost every boat I board for whatever reason has one or more serious electrical safety issues, and some of the most surprised are those who claimed their boat was safe.
Biggest culprits:
1. Improperly installed VHF radio. (Arguably most important safety device on boat).
2. Inadequate or improperly installed bilge pump.
3. Improperly installed battery charger.
The list goes on. I've seen boaters complain that the surveyor was too critical, only then open a locker to find a rats nest of loose wires, wire nuts, unravelling electrical tape, wire nuts, shorted battery selector switches, crimp connections that fall off if one touches them, and so on.
Most folks know not to frig with the 120Vac system, but few realize that the 12Vdc electrical system will burn your boat to the waterline if not wired properly, almost as easily.
So I recommend getting a survey whether the insurance company requires it or not.
ramblinrod
www.sheenmarine.com