The Importance of Boat Hot Water Heaters and Why You Need One

MARINE HOT WATER HEATERS are essential if you own a boat because they provide a place for hot water storage. Not all boats have HOT WATERHEATER. If you are fortunate, when you buy a new boat, the boat’s water system will comprise a hot water heater. MARINE HEATERS are quite different from the ones found in homes everywhere. This is because the marine environment is extremely harsh, corroding everything that it comes in contact with. Add to this the fact that the systems which feed the heater are very different, and you can understand why a marine designed and built water heater is necessary.


Hot water heaters get their heat from two sources:



As the boat is moving along, the main engine heat exchanger, moves heat through coils located in the water heater. The coils are what heat the water inside of the water heater.

Next, a 110V electric heating element which has been placed deep within the water heater is capable of heating the water. If away from the dock, it is worth noting that 110v can be supplied by use of shore power or an on board generator.


The primary safety concern is the temperature of the water delivered by the faucet. Minus any temperature controls, you need to mix in cold water at the taps to avoid possibly being scalded by water that is way too hot.

Engine hot water can be as much as 180 degrees. In order to regulate this temperature you have two options. You can have a temperature mixing valve placed on the tank, or have an automatic temperature control placed on the faucet.

The fact of the matter is that 120v heating elements are much less difficult to control because they can be adjusted to regulate whatever water temperature is required in the water supply.

If the thermostat that operates the electric heating element should fail to function properly, and the temperature of the water in the heater reaches the boiling point, steam will be created, and severe pressure, the pressure relief valve will open and allow the pressure to vent before the circumstances reach crisis proportions. In the even the pressure relief valve fails to operate correctly or at all, or if it has been capped, then it won’t be able to provide the necessary safety backup.

Even when the pressure relief valve is functioning properly it can still pose a hazard. Pressure relief valves can vent unexpectedly, flooding the area with boiling water and steam. This can happen if the thermostat is wired incorrectly, causing it to bypass its essential control function, leaving the heating element being constantly energized.

It is for this reason that the discharge of a water heater’s pressure relief valve should be plumbed into the bilge or away from locations where people may be at any given time. Cheap hosing or tubing merely slipped over the valve’s outlet pipe is not sufficient, as it can be blown off by high pressure and steam. It must be highly durable and securely clamped into place if it is to be effective.

If the engine’s cooling system fails to operate as it should due to a manufacturing or design flaw, the manufacturer of the engine is ordinarily held responsible for the cost of repairs, but only if the engine is under warranty. However, if the plumbing between the engine and the water heater fails, the engine is guaranteed to overheat and it may ultimately explode.

You should be aware that if this is the case, the engine manufacturer has no liability for this. This is why you need to be absolutely positive that the hose used to connect the engine’s cooling system to the water heater is extremely strong.

Yes, there are plenty of regular “heater hoses”, available, but one of these may not be able to handle all that is asked of it. These hoses have a tendency to chafe, king, and become crushed when maneuvered through the boat.


Faucets are ideal for water system lines. Manual pumping needs only your regular spigots, as in a pressure water system, boat faucets are scarcely different from those found on shore. The main differences occur in styling and that they may possibly be fitted with hose backs. You need two connections for mixer faucets, one from the cold side to the supply line from the pump and the other from the hot side to the water heater.


These are the same as faucet connections. The only difference is that instead of bringing the water through a spigot, the water comes through a pipe or hose to the shower head.


Sink drains usually connect with a reinforced rubber hose to what is called a through-hull fitting. In the case of a sailboat, sinks are placed near the boat’s centerline. his is done to ensure that heeling won’t put them below the waterline. Because head sinks are often located well outboard, they may be plumbed to drain into the bowl of the toilet to avoid the risk of flooding.

Shower pans too drain frequently drain into the bilge to be pumped overboard by the bilge pump. However, this method down the road, will lead to nasty bilge odors, plus there is the risk of clogging the bilge pump with hair. It is necessary to keep shower pans isolated from the bilge and include a discharge pump, which would be either operated automatically or connected to a switch. It is essential that the through-hull discharge outlet always remain above the water.


The S360EW is an electric only 12V water heater that hasn’t been around all that long in the marine industry. It is the perfect solution for outboards as the water heater connects to a 12V power supply, which means that it isn’t necessary to have a generator, inverter or shore power. The compact design of the water heater means it can fit in small spaces, and electric merely means installation isn’t tied to the engine room. Rather, the water heater can be fitted in the galley transom or other storage spaces simply and this makes for more space on the boat.

The water heater has a quick heat up time with the ability to produce hot water in under an hour. It is highly efficient with heat retention of up to as long as 10 hours. The heater is perfect for use with deck showers and a warming wet suit, and supplies 3 gallons of hot water at a time.

With all Whale water heaters safety is the priority and the 12V water heater is made to the best of their ability. It comes with integrated temperature and a pressure valve, plus a thermal cut out and heat indication. The heater further has an integrated anode for longer life and the relay allows for switching at the helm for ease of use and control.


This is an example of the type of BOAT HOT WATER HEATER that you should have on your boat.

Your boat is your home away from home. Just as you invest money, time, and effort in your house to create the living environment you want, your boat deserves the same treatment. That means having the proper equipment and accessories that go with boat ownership.

Compared to the energy devouring residential water heaters out there, marine water heaters are far more convenient and made to be as energy-efficient as possible. Your heater will work best if you select the proper size and install it in the correct manner to get the most out of your unit and ensure reliability.

So how exactly do you choose the right HEATER with such a vast array available on the market?

This is where the Whale 6 Gallon Premium Water Heater comes in. This unbelievable unit is a 6 gallon capacity, 12V BOAT WATER HEATER with a double-walled front heater exchange system.

This double-walled heat exchange system enlists the help of the boat’s engine to heat the water. The water is heated by the engine’s closed cooling system. The heating process is remarkably efficient due to the double-walled heat exchange.

The Whale Premium is intricately designed to withstand all kinds of weather, including the often harsh marine conditions. In addition, they are equipped with the latest technology to ensure energy efficiency and durability. This is why there are 3 types of material for this marine water heater that you can make your selection from:


This material provides solid resistance against erosion. Even though it weighs more than other types of Whale Premium materials, it’s extremely solid and durable. That is important, particularly if you do a lot of sailing during the hot weather.


Anything made of stainless steel has a sophisticated and modern appearance. In addition, it’s also highly functional. This unit carries with it a high level of resistance to corrosion while bringing a modern touch to your boat. This material is also a lot lighter than galvanized steel.


This unit looks fantastic in your engine room. Its white body mixes well with all of the other equipment, and it’s practically made to be installed in private sailboat engine rooms. The hardware of this unit has an aluminum coating, so this provides corrosion resistance.

The many great features and advantages of the Whale Premium water heater are, what makes it rank among the best on the market. While the three materials you can choose from are great all by themselves, what makes this unit even better is the multiple versions which meet any installation requirements.

This marine water heater is number one in safety too. It is ignition-protected and has an integrated pressure relief valve that ensures the optimum pressure level.

It also has a temperature and pressure drain tube. Moreover, it’s advised that you get the magnesium anodes to keep corrosion at bay and extend the life of your water heater. The only thing you might have an issue with is the fact that this unit can only be mounted horizontally.

Ultimately, buying a marine water heater is one of the smartest investments you can make for your boat.


1. LOCATION OF WATER HEATER — It is essential that the heat exchanger for the water heater be no higher than the exchanger for the main engine. Should this prove not to be the case, a remote expansion tank must be added.

2. WATER HEATER SHOULD BE CLOSE TO THE MAIN ENGINE — This is so that the length of hose used and amount of heat loss is reduced.

3. FOLLOW INSTRUCTIONS — Always follow the instructions given by the manufacturer of the water heater.

4. HOT WATER HOSES — It is advised that hot water hoses should be of very high quality; SAEJ2006 (wet exhaust) hoses are the preferred choice for this. Hoses that are of a lower quality are in danger of rupturing due to the heat.

5. CONNECTING WATER TO ENGINE’S CLOSED COOLING SYSTEM — The height of the water heater is the problem here. If the heat exchanger inside the water heater or any part of the plumbing located between the engine and the water heater is above the engine’s expansion tank cap, then a remote expansion tank must be connected into the system.


Before you rush out to buy a marine water heater, you need to know the exact size of your boat. This is because how big your boat is directly affects the size of the marine water heater that you can get. It’s essential to measure precisely how much space there is in the area where you plan to mount your water heater. Once you’ve determined this, you need to find out if the area requires a rear or side-mount.

The reason for this is that a boat’s available space is frequently limited, and nearly every inch of space is accounted for. When you know all these facts, you can select the best marine water heater for your boat.

The next thing you have to figure out is how many people are normally on your boat. This is necessary because the amount of people on board will affect the capacity of the marine water heater you should purchase.

It goes without saying that the more people you have on board, the larger marine water heater capacity you will require.

Keep these things in mind when you are purchasing a marine water heater:


Essentially all boats are now electrically powered due to the fact that electric powered models tend to be more reliable and have better endurance. Also, the unit doesn’t have to fight hard to get power.

A unite powered by propane is desired for its swift recovery rate, particularly at very low temperatures. Also, these units are famous for their lower running cost.

While an electric powered model does last longer, propane powered water heaters such as the Isotherm marine water heater or the Rarity hot water heater are also known to last long.


Not only is size a consideration, but the larger the unit, the more it weighs, and you shouldn’t be adding a lot of weight to your boat or you are going to have a detrimental affect on its stability. You also have to consider how well a unit is going to meet your needs.

If you do in fact need a water heater, but are worried about the amount of space it will take up, think about getting a tankless water heater, which is a lot smaller and lighter.


It is vital that you select the right material for your hot water heater. Marine water heaters are forced to endure severe weather. To pick the correct one, you have to think about your boating style.

Do you frequently boat on freshwater or do you prefer the open sea? You have to think about these things in order to determine the material your marine water heater casing needs to be made of.

If you’re feeling unsure, it’s recommended that you opt for a stainless steel casing because it is strong and durable against all conditions and atmospheres.


A word of advice here. Before you consider brand, you should give careful consideration to a marine water heater’s abilities and functions.

This isn’t to say that brand isn’t important. Good brands have earned their reputations by proving to be trustworthy. Brands you might like to try are Kuuma or Quick.


This is one of the most disregarded factors in regards to marine water heaters. While doing your homework, (research) before you purchase a MARINE HOT WATER HEATER is essential, it’s also equally important that you are capable of troubleshooting any difficulties that may arise with the water heater company.


The longer you’ve been boating, the better you understand just how much you need a marine water heater. It doesn’t matter if you it’s for potable use or washing up, whenever you’re far from shore it’s always necessary to have hot water easily available.


Frequently for users of marine water heaters, comfort is the top reason for having one. You can have easy access to hot water while onboard your boat at any given time.


A lot of people like to shower in hot water because it eliminates dirt and the salt of the ocean better. keeping the boat clean is a vital part of boating.


Given the progress of improved technology and more effective energy saving methods, marine water heaters are now a lot less expensive.


Most marine water heaters are quite user-friendly and not difficult to install. There’s no in-wall plumbing or wiring like there is with a residential water heater, and it there aren’t a whole bunch of bewildering components to puzzle you.

Furthermore, it’s easy to service and maintain. It’s not uncommon to find boat owners who can install a unit all by themselves.


Often marine water heaters are not difficult to install. They come with detailed but easy to follow instruction manuals. Truth be told, lots of boaters would rather install the marine water heater themselves.

If that’s not the case, you can choose to hire someone from the marine water heater company. After it’s installed and you want to use it? All you need to do is turn it on and wait a little bit, then you will have hot water.


You will have to check your marine water heater on a regular basis. Usually a marine water heater comes with a warranty, so you can easily get help with any issue or component replacement if need be.

You have to realize that marine water heaters are designed to endure and tolerate harsh weather conditions. They’re generally very strong and so damage or malfunctioning doesn’t occur often.

In addition, marine water heaters don’t have many varying forms. This makes installation relatively easy. In general, marine water heaters can be categorized like this:

. WITH OR WITHOUT TANKS — Taking into consideration the size of the available space, you can opt for a marine water heater that either has a tank or is tankless. While tankless water heaters do take up a lot less space, most boaters prefer those with tanks because the others frequently breakdown.

This is why a marine water heater with a tank, although much larger, is the better option, because it has a more effective water heating system.

. CAPACITY — One of the most prominent differences between marine water heaters is their capacity. They usually come in 6 gallon, 11 gallon, or 20 gallon sizes.

. HEAT EXCHANGER — Marine water heaters have two kinds of heat exchangers. Front or back.

. VOLTAGE USE — The normal AV voltage for marine water heaters is 120V or 240V.

. MOUNT — There are several ways a marine water heater can be mounted. To accommodate the area on the boat in which it will be installed, it can be mounted either from the rear or side, and some marine water heaters can be mounted vertically or horizontally.

Due to the fact that hey are so convenient, there are a vast number of marine water heaters out on the market nowadays. Be sure that you read many marine hot water heater reviews before you make your final, it’s guaranteed that you will change your mind at least once, because you don’t want to wind up purchasing a low quality unit that isn’t capable of doing its job properly.

Don’t forget the importance of the scale of usage either. For many boaters the 6 gallon marine water heater is adequate for washing and some domestic use. But if you have a bigger boat or more people on board, then you can get a water heater that can hold up to 20 gallons of water. That’s why it’s so essential that you know the scale of usage before you make that final decision.


On a boat you must have enough freshwater at all times. To keep a steady supply you need some type of storage, which is usually supplied in any boat. How you use the water is dependent upon how many people are on the boat.

It is necessary to replenish this water. Sometimes, due to the size of the boat, its owners have to increase their the size of their storage tanks to a large capacity. Here a word of caution. Keep in mind that marine life must be protected by not releasing unsafe water into the marine ecosystem.


If you either currently have or are installing a hot water heater you need to add emptying the hot water tank to your list of winterizing duties. Water that remains in the tank will freeze and can split tubes and hoses.


Not all, but certain engine manufacturers advise that cooling systems be flushed periodically. To accomplish this you need to isolate the heater from the engine.


Without a doubt, one of the best water heaters on the market is Isotemp which is manufactured by Italian manufacturer Indel. The units are created from pure stainless steel for the inner jacket and outcasting, plus tubes and tanks which come into contact with water. Stainless steel is the best material to protect from corrosion.

Besides having the best, top notch materials, Isotemp has safety features such as the mixing thermostat and further features to prevent the cold water from mixing with the hot water. Some of their models even have dual heat exchangers for the ultimate in performance.

A MARINE WATER HEATER is an excellent investment. Having easy access to hot water when boating is a great thing. There is no doubt that having a marine water heater on your boat can do much to increase your pleasure in this activity. It doesn’t matter what you need it for, having hot water at your fingertips is a real pleasure. And you will find that you will be the envy of your boating peers who lack this essential amenity.


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