At the end of a wonderful day aboard, a hot shower is like heaven. That hot shower is even better when you don’t have to lug your towel, clean clothes, shower shoes, soap and shampoo all the way up the dock to the marina washroom. And, that marina shower isn’t an option when you’re swinging on the hook at a secluded anchorage. Hot water aboard your boat is greatly appreciated for showers, washing dishes, clothing or rinsing off the salt after a swim from the aft deck. Ask Captain Chris 772-205-1859
It is important to know how much hot water you need aboard your boat. But first let’s talk about how it is heated. Your house ashore may have a 40 gallon or larger water heater. Most residential homes use either gas flame or electrical heating elements. The usual temperature for your home water heater is around 120 degrees Fahrenheit. A typical shower water temperature may average 105 degrees Fahrenheit. So, let’s think about how that water comes from the tank to you. When you adjust the hot and cold water faucet control knobs you are testing the temperature to satisfy your personal comfort.
How Do You Make Hot Water Aboard?
On your boat the water may be heated by one or both of two heat sources. The first source is electricity. If your water heater is electrically powered then it uses 110 or 220 volts of Alternating Current or AC power. The electricity is either supplied by the shore power at the marina or your onboard generator when at anchor or underway. Be sure to turn the water heater circuit breaker on or you’ll be disappointed with a cold shower.
Or, your boat water heater may be supplemented by your boat’s propulsion engine. The engine coolant is directed through a hose from the propulsion engine to the water heater in a closed loop.
This is an easy idea to understand…and these photos can help. The engine gets hot from the combustion cycles. The coolant aka anti-freeze cools the engine through a closed loop. The liquid coolant recirculates through a heat exchanger that uses raw water to cool the liquid and then back to cool the engine again.
Take that same hot coolant and send it to the domestic water heater in an optional closed loop. The heat from the hose of the hot coolant enters the water heater. The heat transfer occurs inside the water heater tank, heating the water inside the tank just like a heat exchanger (see photo with overhead view of an open water heater tank). This is a great use of the hot coolant. This process doesn’t take any more energy or electricity to heat the water.
Too Hot to Handle
But there is a serious end result to consider. The hot water in the tank may now reach a high temperature near the engine temperature. That’s hot!
So you may have hot water nearing 180 degrees Fahrenheit, much higher than your home water heater. You must not only be aware of this fact and but also warn your boat guests. The hot water is really HOT. If your guests are not aware they may burn or scald themselves when showering or washing their hands. Check out this video that proves the heat that you can achieve.
The other end result is that you may need to use less hot water when showering, doing laundry or doing dishes in the galley. And, you will not need to waste water when you adjust the temperature waiting for hot water to arrive. It’s there in a jiffy!
Once you have learned this is an advantage you can use the higher hot water temperature to extend your nice hot shower instead of taking the fabled “Navy Shower” not just to save water but to extend the hot water availability for the rest of your crew.
Water Heater Options
If your boat has the feature of using hot engine coolant to heat the domestic water you may be uncomfortable with such extreme temperatures. Or you may just want the option to turn this feature on or off. That’s a simple task that’s easy to learn and simple to do. You can turn off the coolant loop to the water heater tank by locating the two valves on the engine system. Follow the two heater hoses from the water heater back to the engine and turn off both valves. This prevents the hot coolant from heating the water tank. It also provides you a method of isolating the engine from the water heater in case there is a hose rupture. You are back to heating your domestic water by shore power or generator electricity. And you can safely continue your cruise.
Ask Captain Chris 772-205-1859
To learn more about this and other easy DIY projects give us a call: 772-205-1859 or email us Chris@captainchrisyachtservices.com
We hope you enjoyed this article reprinted from SOUTHERN BOATING MAGAZINE and written byCaptains Chris & Alyse Caldwell – USCG 100 ton Masters and Cruising Coaches who offer Personal Boat Training Online or Onboard your boat anywhere! Build your cruising confidence with hands-on training, watching AskCaptainChris.com training videos, at 2-day seminars filled with tons of tips for the boater who loves learning. Questions? Ask Captain Chris 772-205-1859 oe email your questions to chris@captainchrisyachtservices.com
