Kemah, Texas
Phone - (409) 539-0250

Friday, February 4, 2011

Marine Reverse Cycle AC/Heat

Marine Reverse Cycle AC/Heat - How does it work?
Cooling and heating with a reverse cycle marine heat pump is a simple process of moving heat from one place to another, by using a refrigerant and a mechanical method.  The heat is either removed from the boats interior air and disposed into the seawater or removed from the seawater and circulated into the boats living area.  Refrigerant reacts easily to temperature and pressure, while changing states similarly easy (liquid to gas, gas to liquid).  When a change occurs in the state of a refrigerant, heat is either absorbed or released; we use compression or a change of pressure to make this happen.

Check out our latest Tech Locker update to learn more.

Thursday, January 27, 2011

NMEA 2000 - Important stuff to know

NMEA 2000, a simple and effective communication for your boat.  One concern with this communication system is on a boat. 

Visualize this, you are on a boat in a shipping channel, that has a NMEA 2000 network controlling the navigation, tankage and even the engine throttle and shifting, the network goes down, you are dead in the water.  Knowing how the NMEA 2000 network is assembled suddenly becomes very important.

Every boat owner that has NMEA 2000 controlling the engine systems or relies on a NMEA 2000 navigation system, should know how the network is assembled and what it would take to troubleshoot a problem.  Taking a few hours to learn this simple system could turn around a very upsetting weekend.  They say that a "little knowledge is dangerous", I say that a whole lot of ignorance can mess your day up!  You don't have to be a "MacGyver" to get the system back up and moving in the right direction.

To learn more, visit our Tech Locker at

Tuesday, January 25, 2011

Corrosion - What we cannot see can harm your boat

As boaters, we often get out on the water after a long week at the office, relishing the moments that we can spend floating with friends and family.  We untie the dock lines, motor our boats away from their comfortable slips, and feel the thrill as the boat increases speed.  As we head out to the open water, we are probably thinking of the fishing, water sports or sailing we’re about to do.  We almost certainly are not thinking, "What has been happening above and below the waterline?"

Today I have updated the "Tech Locker" of our website that goes deep into the topic of corrosion.  The two major concerns being:
  1. Mechanical corrosion - Cavitation
  2. Electro-chemical corrosion - Galvanic and Stray Current
Almost daily, I have someone ask the question "My zincs are dissappearing, how do I protect my boat?"  If this is a question that has come to mind in the past, check out the information that we have compiled concerning galvanic isolators and isolation transformers.  I hope that this information is a value to your boating experience.

Tuesday, January 18, 2011

RCDs - How do we protect an entire circuit?

In conjunction with the previous blog posts, I wanted to answer a question that was raised; How do I protect my outlet circuits without having to change my current outlets?  Many boats have special cover plates made of teak, replacing the outlet to go to GFCI would require replacement of the cover plate and change the look of the boat.  RCDs are the solution to this problem.

Residual Current Devices (RCDs) respond to leakage of electrical current outside of the intended circuit path. When the RCD function is combined with overload and short circuit protection, the device is often referred to as an RCBO. A device that trips on leakages of nominally 5mA, and meets certain standards, is called a Ground Fault Circuit Interrupter (GFCI). A device meeting the same standards but with a trip level of 30mA is called an Electrical Leakage Circuit Interrupter (ELCI). The device to the right provides GFCI or ELCI functions and circuit protection in panel mounted breakers.  RCDs come in various sizes from 15 amp to 30 or 50 amp and can be used with 120 or 240 volt systems.  Make note, the size of the RCD can vary and the spaces that will be consumed in your electrical panel will increase with the size of the RCD.  As an example, a single circuit RCD will fill two positions in your electrical panel.

RCDs operate just like the GFCI you would find in your home or boat, they simply will protect the entire circuit to include the wiring that runs throughout your boat.  This is very important on a boat due to the flex and vibration that are an everyday occurrence, that will eventually take a toll on the the  electrical wiring.  Wire chafe is often found when removing old wiring, this chafe produced from wiring passing through bulkheads or under metal objects.  

In most cases, RCDs can replace the existing main A/C breaker (used as an ELCI), an individual circuit breaker or be added to an existing circuit depending on the existing circuitry.  It becomes an inexpensive solution that can be added to any boat.

To summarize the last couple blog posts, ELCIs will cover an entire boat, RCDs can protect an entire boat or each individual circuit and GFCIs offer protection to the individual outlet or string of outlets (if connected properly).  I hope that this sheds some light on electrical safety devices that can protect our boats and crew.

Monday, January 17, 2011

What is an ELCI? - Current protection for the entire boat!

When digging around the internet to check on any new ABYC regulations I came across some great information provided by Blue Sea Systems.  I wanted to pass this information on to anyone that is asking a question that many boaters ask; How do I detect or prevent "Stray Current"?  An ELCI, Equipment Leakage Circuit Interrupter, can do that and more.

There are two potential failures in a boat′s electrical system that can put people on or around the boat at risk of lethal electric shock.  In a properly functioning marine electrical system, the same amount of AC current flows in the hot and neutral wires.

Properly Functioning Marine Electrical System
However, if electricity “leaks” from this intended path in these two wires to ground, this condition is called a ground fault. A good example of this is an insulation failure in the wiring of an appliance.
Ground Fault
In addition, a faulty ground can occur when the grounding path is broken through a loose connection or broken wire. For instance, a shore power cord ground wire may fail due to constant motion and stress.
Faulty Ground
Faulty grounds can be undetectable; a simple continuity test will not necessarily reveal a problem.
When these two conditions occur at the same time, the results may be tragic. The combination of a ground fault and a faulty ground can result in metal parts in the boat and under water becoming energized.
In addition to the hazard to people on the vessel, there is a larger danger to swimmers near the boat. While people on board are likely to receive a shock from touching energized metal parts, nearby swimmers could receive a paralyzing dose of electricity and drown due to involuntary loss of muscle control. A Coast Guard sponsored study showed numerous instances of electrical leakage causing drowning or potential drowning even though the shock did not directly cause electrocution.
Given the seriousness of the problem, ABYC requirements now include specific measures for avoiding this danger.
ABYC regulation E–13.3.5 states:
    If installed in a head, galley, machinery space, or on a weather deck, the receptacle shall be protected by a Type A (nominal 5 milliamperes) Ground Fault Circuit Interrupter (GFCI).
ABYC regulation E–11.11.1 states:
    An Equipment Leakage Circuit Interrupter (ELCI) shall be installed with or in addition to the main shore power disconnect circuit breaker(s) or at the additional overcurrent protection as required by E11. whichever is closer to the shore power connection.
ELCIs, and the more familiar GFCIs, are part of a larger family of devices that measure current flow in the hot and neutral wires and immediately switch the electricity off if an imbalance of current flow is detected. ELCIs and GFCIs that are also Residual Current Circuit Breakers (RCBO) provide overcurrent tripping protection characteristic of a normal circuit breaker.
GFCIs are used as branch circuit ground fault protection at the 5mA threshold in potentially wet environments. GFCIs protect against flaws in devices plugged into them, but offer no protection from the danger of a failing hard-wired appliance, such as a water heater or cooktop.
In contrast, an ELCI provides additional whole-boat protection. Installed as required within 10' of the shore power inlet, an ELCI provides 30mA ground fault protection for the entire AC shore power system beyond the ELCI. ABYC regulations still require the use of GFCIs in environments described above.
ELCI Placement
Although ABYC regulations apply only to new boat construction, the dangers and liabilities exist for any boat owner with a shore power connection. Retrofitting an ELCI to an existing AC system can be worthwhile “insurance” against risk. Since an ELCI/RCBO can serve as the main shore power circuit breaker, it can replace a standard circuit breaker in this application. Alternatively, an ELCI/RCBO can be added between the shore power inlet and the existing main shore power circuit breaker.
Safety ground system failures on boats are safety and liability disasters waiting to happen. ELCI protection on each shore power line, combined with protection afforded by GFCIs, will reduce risk to those on the boat, the dock, and in the water surrounding the boat.

GFCIs are great at protecting the devices that are plugged into them and the individuals that might be using it, they do not protect anything that is upstream on the electrical circuit.  Standard circuit breakers protect the circuit and everything downstream, yet sometimes they do not act quick enough to avoid fire or shock.  ELCI/RCBOs fill the gap that the others miss.

We hope that this information can answer some questions and make your boating experience a safer one.  Add your questions or comments if you like, we welcome the chance to discuss this valuable topic.

Friday, January 14, 2011

GFCI Danger! Something we all need to know!

In this past week, I was called out to a boat for an "electrical glitch" and found this, a little more than a glitch:
What the photo does not show is the fire and smoke that had also filled the boat.  This boat owner was extremely lucky, we were able to extinguish the fire in a matter of minutes and save the boat.  It would have otherwise surely destroyed the boat.

A Ground Fault Circuit Interrupter (GFCI) is an important part of our house and boat. It protects us against electrical shock.  A GFCI monitors the amount of current flowing from hot to neutral.  A GFCI can detect how much current is flowing to the receptacle on the "hot," or black wire, and then looks for the exact same amount flowing back on the "neutral," or white wire.  If there is any imbalance, it trips the circuit.  It is able to sense a mismatch as small as 4 or 5 milliamps, and it can react as quickly as one-thirtieth of a second.  This is great for protecting us against electrical shock, however what happens when we add saltwater or humid saltwater-rich air?  Corrosion and potential for fire.

In the photos above, the GFCI outlet was installed from the factory and installed on the vessel's exterior.  The manufacturer is a very prestigious, high-end producer of motor yachts known for building some of the best yachts in the world.  There were three outlets on the outside of the boat; each was installed in the same manner.  The manufacturer used a water-resistant cover that was spring loaded to help keep the elements out of the circuit; however, a number of errors were made in the installation.  First: they used a household approved outlet, something that can be obtained from a hardware store, NOT a marine-grade outlet.  The second is that the outlet was installed without using an electrical box.  Third, they installed this outlet exterior of the ship's cabin.  I would like to take a moment to explain each of these errors and hope to show you why these were bad decisions:
  1. Marine grade GFCI - All of the copper connections inside this device are tinned to help stop corrosion.  The household grade GFCIs will corrode, giving the potential for electrical arching.  When this arching occurs, it creates enough heat to start a fire.
  2. Electrical boxes have three functions: 1.) to prevent accidental electrical shock 2.) to keep the elements out and 3.) to minimize the amount of oxygen should a fire occur.  Without an electrical box, salt air was able to attack the GFCI and when the fire occurred, it gave the fire unlimited amounts of oxygen to allow it to expand unchecked.  If a fire occurs inside an electrical box, it will be starved for oxygen, extinguishing itself rather quickly.
  3. Using a GFCI on an external circuit is simply asking for trouble.  The elements will get to the device easier and more rapidly.  It would be better to install the GFCI in a location inside the cabin and protect the exterior outlet downstream.  By doing so, not only do you take the GFCI out of the elements but you also protect all of the wiring that goes to the outlet.
In the case above, we had contacted the manufacturer to discuss the problem and they  agreed that this is not the first case brought to their attention.  They advised us that all of the exterior GFCIs must be removed and protected from inside the ship's cabin, preferably near the electrical panel where the power begins.

I am a firm believer in GFCI circuits, they save lives!  Caution needs to be taken where they are used and how they are wired.  No boater wants to hear of this happening to any boat.  Post any of your questions here, I would be glad to answer them.

Sunday, January 9, 2011

Water Maker DIY - Part II

Today is the final post on the topic of reverse osmosis water maker systems.  In the previous post we discussed the systems needed to take water from the sea, pump it, filter it and then run it through the high pressure pump and RO membrane.  Today's topics will give more information on the things that are not usually seen: the things that keep everything running and doing what they are meant to do. 

Post RO
Automation is a convenience, but it is a convenience that I will not live without on the system that I would construct.  Yes, you could do everything manually, like changing valve positions, turning on pumps, and increasing or decreasing system pressures.  However, if you are going to have a water maker system that will last for many years to come, automation takes out some of the human error that is bound to occur.  

There are many different vendors supplying controls to run an RO water maker.  The determining factors are the amount of automation you want, the size of your water maker, the amount of power you have available and what you're willing to spend.  I am considering a Series 150 microprocessor controller made by R&D Specialties however there are numerous controllers available. Here is some information provided by HCTI:

•Economical compact package
•Liquid crystal display and multi-function keypad
•English or metric TDS and temperature values
•Visual and audible alarm, with alarm silence key
•Programmable time delays and set points
•Programmable flush mode
•Low pressure automatic reset
•NEMA 4X hinged enclosure
•Panel or frame mount
•Available with UL/CUL Listing
R&D Specialties, Series 150 RO Controller
Standard functions of the Series 150 controller are the monitoring and/or control of:
•RO high pressure pump motor
•Inlet solenoid valve
•Automatic flush solenoid valve
•Low feed pressure switch
•High pump pressure switch
•RO storage tank level switches (1 or 2)
•Permeate TDS/Conductivity
•Water temperature
•Pre-treat lockout
•Operating hours
•RO tank full override
 *TDS stands for Total Dissolved Solids 

Switch Inputs, Dry Contact:
• Pressure fault - low feed and/or high pump pressure
•Tank level high
•Tank level low
•Pickled treatment lockout
Relay Outputs:
•High pressure pump relay - 120/240V, 1 HP
•Inlet valve relay - 120/240V, 5 AMP
•Flush Valve relay - 120/240V, 5 AMP
•Relays supply same output voltage as board power (120 or 240V, VAC)

Valves/Water Control
I have seen numerous RO systems that have no automation and work very well, as long as the operator understands the system completely.  Knowing the water flow during each of the water making processes, start-up and fresh water flush can be difficult for someone that does not do this on a regular basis.   

In the system that I would design, complete automation is a requirement.  I want to be sure that anyone can operate the system even when I am not there to instruct.  Most good RO water maker controllers will have the inputs and outputs to control solenoid valves as needed.  The three way valves that will be used in this application will simply connect into the outputs on the controller.  Another function that would be handy, yet is not a must, is an automatic shut-off when the holding tanks are full.  Royce Industries makes an electronic level sensor that could be used to shut off the system when needed.  I know that I would often forget to monitor the water tank levels and it would be nice to know that the system is doing this for me.

Post Filtration
Post filtration such as carbon filters and pH neutralizers will simply help the flavor of the product water.  I feel it is a matter of preference rather than need.  In the system that I install, this will not be needed, yet could easily be installed at a later date if I so desire.  
UV Sterilizer
Ultraviolet Sterilizer
A U.V. sterilizer is recommended if the feed water (intake) is from a harbor, marina, or polluted source. The RO membrane rejects bacteria and viruses, however if biological migration occurs across the membrane, then the U.V. sterilizer will destroy 99.9 % of any biological intrusion in the product water.

Fresh Water Flush
Fresh water is required to flush or store the water maker.  Fresh water flush will greatly prolong the life of the reverse osmosis membrane elements by rinsing them with fresh water.  The fresh water flush will need to repeat itself every seven days.  By rinsing the water maker, salt water is displaced with fresh water within the RO system’s internal parts. This process will prevent corrosion of the internal parts and also reduce biological fouling of the membranes.

The fresh water used to flush the RO system is taken from the boat's pressurized fresh water system.  To ensure that chlorine does not enter the system, the pressurized water should go through a carbon filter first.  The carbon filter will remove any chlorine that might have entered the tanks when filling at the marina.
After the fresh water goes through the carbon filte,r it is a good idea to introduce it to the water maker at a “T” before or after the sediment filters.  If the fresh water is introduced before the sediment filters, it will offer additional protection to these filter cartridges.

According to one manufacturer of the RO membranes, membranes age as they sit unused. So delay the purchase of your membranes until after you finish installing the rest of the RO system and you are ready to use the system.

The process of pickling, consists of adding a food preservative (sodium metabisulphite) to stop bacterial and fungal growth on the membranes and in the pressure vessel, is widely regarded as being effective for at least 3 months. I know of several RO systems on yachts that have been pickled for 1 year or more. One disadvantage to pickling is, the preservative leaves its mark on hoses (especially PVC), bronze fittings and stainless steel.  Given the option, I would prefer not to pickle the RO membranes but instead flush them frequently with unchlorinated fresh water.  The frequency of fresh water flush depends on ambient temperature: the warmer the temperatures, the more frequent a fresh water flush will be required.

Control automation is key to keeping the system clean and operational every time you will need it.  Many microprocessor controlled systems will give you the ability to program the frequency of fresh water flush.  Membranes can be pricy and forgetting to flush the membrane could result in added expense.  Water maker controllers can be a great insurance policy.

Ensuring that you have a properly functioning RO water system
Important things to DO: 
  1. Change the cartridge filters regularly. 
  2. Monitor the system and keep a log daily.
  3. Run the system, as much as possible, on a continuous basis.
  4. Pickle the system if you do not intend to operate for long periods.
Important things NOT to do:
  1. Permit chlorine in the feed water.
  2. Shut down the system for extended periods without pickling.
  3. Close the throttle (pressure) valve completely.
  4. Operate the system with insufficient feed flow.
  5. Allow the membrane to become dry. 
Water Temperature - How does this affect the operation?
Temperature of the feed water can affect the water maker's ability or inability to make fresh water.  As the temperature of the feed water drops, so will the fresh water production.  As the temperature of the feed water increases, the fresh water production should also increase.  With this known, a decrease in feed water temperature can be compensated by increasing the feed pressure up to the maximum allowed by the membrane, pump and associated components.  Once the maximum pressure is reached, a further decreasing temperature causes the permeate flow to decrease and nothing more can be done.  Increasing temperature is compensated by lowering the feed pressure.

Seawater/brackish water operation-What might we change?
Feed water salinity can also affect the water maker’s ability and efficiency.  An increase in the feed water salinity can be compensated by increasing the feed pressure up to the maximum. If further pressure increase is not possible, than a lowered permeate flow and system recovery has to be accepted.  A lower feed water salinity, such as the brackish bay water, allows us to decrease the feed pressure and continue to receive the same product water flow.

Now for the most important information of this series, the cost!  Currently the costs for the major components are listed below, however there are additional costs for all the minor components that I have factored into my budget.  When looking at a good water maker system, the costs will be $7,000-$10,000 for a pre-constructed system that will produce more than 100-150 gallons in a day, I think I will easily be able to do better than that.  Here are the items that will put the biggest dent in your checkbook. 
  • Low pressure feed pump     - $250
  • High pressure RO pump      - $750
  • High pressure pump motor - $250
  • High pressure vessel            - $350
  • RO membrane                      - $200
  • RO Controller                       - Awaiting pricing information
So that's it in a nutshell (in three posts!). Water makers mystify a lot of people, but they are really very simple filtration systems once you wrap your brain around exactly how they work. Questions?  Hit me. I'll be happy to answer any questions you might have about your unique situation.