There's lots of talk but actually in reality its much less frequent than people think. Sovereign yachts can have arms if its a Royal yacht and will have body guards but most dont.

If your yacht comes in to Europe you need to declare them and put them in a bonded warehouse. I have contacts of people that can do this in Monaco but its not cheap.

Also members may be a member of a gun club but then they need to keep their arm either at home in a safe, ammunition separate or at the gun club, not at the yacht.

And they have to travel direct between the club and their home and keep guns, bolts, magazines and ammunition all separate for the journey.

A few yachts have weapons but its administratively heavy both with customs and also with flag state and they tend to be antiques; for example like SY Marie had a canon on the back which was fun for regattas in Saint Barths etc.

Its simply not worth it in most cases.

Another owner used to fire clays off the transom for fun but his shot guns were antiques worth more than his car! and non lead shot so you dont pollute the oceans.

Also most people don't consider that standard ammunition is not appropriate for use on a yacht neither are long barrelled rifles . You need special fragmenting ammunition for onboard a yacht which is hard to get hold of, the reason is because with fragmenting ammunition the rounds don't go through the hull or engines, generators and cabin partitions etc and also the last thing you want is a bullet bouncing around in an engine room with ricochets etc. And you need short weapons for fighting in closed up spaces.

Better to hire professional security teams who may bring on weapons for example to transit past Yemen etc. In these situations where a risk has been detected the arms are put on the yacht 12 miles out and taken off the yacht before you go 12 miles in by specialist teams who have the permissions and storage facilities.

There are no secret rooms because the weapons are on display to ward off any pirates should they come.

A secret room is an illogical concept as you can't access the weapons fast.

Yes you will have an impenetrable citadel for the family but not an arms room generally.

And its not a secret as some of the crews job is to get the family there fast if there's an incident.

At the end of the day a fire extinguisher opened up in an adversaries face is a far more effective weapon and less legally contentious than a hand gun.

UBO's do have body guards on the yachts, those generally don't carry a fire arm but may have non lethal force e.g. pepper, stun gun, batton etc but even those have got captains in trouble in the past so be-careful having any of those on board.

The most effective is the UBOs body guards brain and their hands, physical presence and their IT and information skills such as cyber security skills at detecting threats, reference checking, crew profiling and guest profiling etc to detect threats way before they ever happen.

Ive also seen a captain disguise his yacht during a suez transit past Yemen he built a fake artillery cannon on the front to visually deter the pirates.

If you get to the stage you need to draw a hand gun then all the body guarding has failed, the best family offices don't fail.

Also note that family offices have teams of lawyers and the general international legal advice is don't pick up an arm as you are showing intent. Acts of piracy in Yachting areas in the Med are very rare and where they are common a hired security team will be contracted on board and work with the family office security head. Normally for these "risky" transits the UBO is not on board anyway.

Guns are for movies now its IT, intelligence first unless you are a Royal yacht then you have exemptions.

Leave the guns at home and enjoy the sailing, if you are going to have a gun onboard get a cannon like SY Marie.