Technical & Equipment from Ocean Sailor Magazine

The Power to Roam

The Power to Roam

110v or 240v? Tom Cooper explains Kraken’s go-Anywhere plug & play solution for sailing the world.

Eighty percent of the world uses 220-240V with the remaining twenty percent using 110-120V.

The twenty percent includes the USA, Canada and the Japan Islands and a few other countries.

How many European or Antipodean cruisers won’t want to visit at least one of these countries as they voyage around the world, and how many American world cruisers don’t want to visit Europe, Australia or New Zealand?

So what’s the solution? At Kraken Yachts we have grasped this thorny problem.

For boats that never leave their home country, the choice is simple – use whatever your resident Voltage AC (VAC) supply is. Normally that is either 240VAC (range 220-240) or 120VAC (range 110-120), but for any owner serious about blue water cruising you need to use the shore power that’s available anywhere in the world. Luckily nowadays, whether you’re a US yacht leaving for Europe or a European yacht heading for the States, the solution is not as complex as it once was.

For a well set-up cruising boat it’s worth considering how to deal with various shore power and electrical issues so that you’re best prepared. This also ensures safety and the long-term resale value to your boat, especially to aspiring world cruisers. 

Depending on where you’re starting from you have to confront the Hertz issue, the frequency of AC electricity, not the hire car company!  

Technically there are multiple ways to ‘skin the cat’ and it’s getting more straightforward with the evolution of electrical products, but, let’s face it, there’s more electrical conveniences wanted by the modern owner, so this subject is becoming more critical.

It is relatively easy to transform 240V down to 120V but the big issue is that the USA, Canada and Taiwan use 60Hz, Japan uses 50 and 60Hz and pretty well the rest of the world uses 50Hz and changing frequency from 60 to 50Hz or the other way round is not easy. 

Sure if you have a superyacht, then there’s the option of a large, heavy and expensive VAC/Hz conversion unit, but for vessels up to 80’ (24mts), this is generally not practical.

Luckily to overcome the hertz issue is nowadays relatively easy with some forward-thinking and planning and the design stage. First, we need to select AC equipment that is dual-frequency. Ten years ago only around 50% of products could be run on 50 or 60Hz. Today that percentage has risen to 90-95%, so we have plenty of brands to choose from across the products we need. 

Most global manufacturers now offer electrical products in 240VAC with both 50/60Hz or 120/240VAC- 50/60Hz, so this has greatly simplified the situation. Having dual hertz equipment is the very key to a world cruising solution.

Kraken’s option for an owner who wants to spend time in areas that have differing hertz frequencies available, is to set the yacht up using only equipment that is compatible for either 50 or 60Hz. 

That leaves the voltage issue to deal with.

US and Canadian marinas offer 240VAC / 60Hz power direct, or as 240V comprising 2 x 120V positives, also at 60Hz and it’s part of their standard supply. Japan, regretfully, is more difficult but 240V is available, we are told, in some of the bigger marinas.

All marinas in the rest of the world offer 240v /50Hz.

There are a number of benefits in supplying the more powerful electrical equipment onboard such as ovens, air conditioners or water makers at 60Hz because you have approx 20% more power available. 

Dual-frequency equipment will continue to run efficiently and safely at 50Hz but will run faster at 60Hz, but we must ensure that at 50Hz, minimum operating speed of equipment is achieved, so you don’t encounter problems of undersupply.

A shore power isolation transformer is necessary to ensure 240VAC – 50/60Hz can be reduced down to 110-120V if required.
It is an important part of the solution.
This type of transformer brings a number of advantages:

On the boat side you can split supply to both 240VAC and 120VAC (if needed)

Reduces a variety of earth connection issues you may otherwise find worldwide, including the US

Self polarizing – eliminating polarity issues

See Fig 1

Whatever the earthing method used, an interruption to integrity in the grounding circuit can pose a serious electrical shock hazard to persons onboard. If the grounding is faulty, a short circuit inside any VAC appliance can cause a fatal accident. With careful electrical design and adequate overcurrent protection a correctly installed isolation transformer will eliminate this risk.

By splitting off 120VAC at the secondary side of a 240VAC isolating transformer we can incorporate 120VAC supply circuits for plug outlets, which provided outlets are clearly marked, comply with US electrical regulations. This means the yacht will have both 240V and 120V plug outlets.

The owner can decide whether this is really necessary as most consumer products such as laptops, audiovisual, phones are designed to operate worldwide on 120/240VAC – 50/60Hz

You must be aware that some devices, such as hairdryers or toasters may not be, so if you spend a considerable amount of time in the USA, Canada, Japan or Taiwan it will be worthwhile having dual-outlet sockets fitted.

Some dedicated equipment not used daily (like a dive compressor) may not suit dual 50/60Hz operation but can always be paired with and run off the generator. It’s essential to check your kit and also ensure all your GPO circuits are clearly marked. Audit your vessel – understand the rating plates.

A vessel must have adequate overcurrent protection including the all-important dual pole protection on the primary side.

If the vessel will only visit areas of the world with 60Hz currents for a few months then the transformer to 120V may be considered unnecessary, as long as you continue to use 240V hand appliances in the sockets, but you need to check they are dual hertz. Most are.

This shore power and operating voltage/hertz is really just an integral part of a complete AC electrical system, encompassing your generator, load schedule, inverter’s loads, usage and compliance.

Owners who want their creature comforts, combined with unlimited cruising restrictions, create the need to fully assess the complete yacht electrical system at design and specification time, but a hassle-free result can be achieved very cost effectively.

A yacht set up like this will operate all over the world, and you will only need to rely on your generator while you eat the world’s finest Sushi!

Share this post

Share on facebook
Share on twitter
Share on linkedin
Share on pinterest
Share on print
Share on email

Keep reading

There’s plenty more to read at Ocean Sailor. Check out some more Technical & Equipment articles …