Well, its been a busy 2016 surveying season so far here on the North Shore of Lake Ontario. We had virtually no spring this year and went right from winter to launch season. Like I said its been very busy and I apologize for my lack of posts these past couple of months. As it usually does, business has dropped off a bit in July and this year is no different but its still going.
In between a myriad of survey inspections and reports I have actually managed to sail my own boat a bit and have that the opportunity to race on ACE a Mumm 36 up and down the north shore and across the lake. In our club’s Wednesday night series I’ve been on a board a C&C 38 so I’ve been busy. On Wednesday this week its aboard ACE again for another across the lake overnighter, the Freeman Cup and after that on Friday, Saturday and Sunday its can racing as part of the LYRA regatta hosted by The Whitby Yacht Club.
ACE, Mumm 36 racer
In the picture above, standing on the side deck is Dirk Stydenga, sailmaker extraordinaire former owner of Performance Sails in Toronto and now hails from Halifax Nova Scotia.
Electroshock Drowning, Prevention. A few days ago I received and enquiry on my Facebook page (thanks Brian) asking about the possibility of testing for stray electrical current leakage in the water at marinas. To that end I thought that I’d talk that very subject in this post. To make a long story relatively short it is possible to test for this but to do so requires specialized equipment. You basically need a Digital Multi Meter which is very sensitive on the low side of AC amps scale and it needs to be equipped with precious metal test leads.
Unfortunately these test results are only good at the time of the test. In other words you could be ok today and not tomorrow Unless you are testing every day or so which is probably not going to happen.
In my opinion, prevention is much better and a more practical solution to the problem than trying to continually monitor for any stray current leakage. The good news is that it’s not difficult to do just that. There is a devise on the market which is easily retrofitted to just about any boat’s on board shore power AC electrical system. It’s called an Electrical Leakage Circuit Interrupter or ELCI . It’s simply a high capacity Ground Fault Interrupter (GFCI) which breaks the circuit if it senses stray current leakage to ground or in our case into the water. You all know what a GFCI is. It’s that AC plug installed in our kitchens and bathrooms in our home that have the little red and black push buttons in the center. If the red button pops you simply press the black button to reset the devise. If it continually trips then you obviously have a problem which needs to be corrected.
To understand how these devises function we need to go back to our basic electrical theory which states that on a properly functioning AC (alternating current) circuit there should be equal current flow on both the hot (black) and the neutral (white) wires. Any current leakage on the circuit, however small will cause an imbalance in this current flow and the ELCI will automatically open and break the circuit.
The main difference between the ELCI and the GFCI are the current levels at which they trip at. The GFCI trips at 5 milliamps which is really too low for to be any use to us and the ELCI trips at 30 milliamps. Enough to serve our purposes but not enough to be harmful. (Remember .6 amps AC = heart failure). The reason that GFCI’s are ineffective for this is that all boats plugged into shore power on any one dock are electrically connected through the shore power grounding circuits and properly functioning boats will usually leak small amounts of current into the water, even under normal conditions. In most cases these current levels are too small to be of any concern. The problem is that they are cumulative (they add up) and can increase to levels, that while are still not dangerous can cause nuisance tripping of the GFCI’s and be a real pain. This is also why, in North America AC power services at the docks rarely have GFCI’s installed. I understand that in other parts of the world GFCI’s are sometimes utilized on docks.
Ok back to the ELCI. Installation is relatively simple. In many cases the main 2 pole circuit breaker at the AC main panel can simply be replaced with one that incorporates the ELCI into it. Otherwise they can be installed as a stand-alone in the main AC feed circuit between the vessel shore power receptacle and the 2 pole main circuit breaker at the on board AC panel. They also are not costly, average about $2-300 USD. Additional information on the ELCI can be found at www.bluesea.com
In addition to the installation of the ELCI it is recommended that the on AC and DC grounding circuits be connected aboard the boat. This is easily done right at the panel.
Electroshock Drowning is a topic in which myself and many others have been very vocal about these past few years and I have written about it many times in my magazine articles. It is a phenomenon which has been occurring in fresh water marinas, cottage docks and anywhere boats are moored and plugged into shore supplied AC (alternating) electrical current. It occurs when AC current, by way of faulty electrical wiring or appliances either on board the boat or on the dock leak current into the water and if persons or animals (yes pets and wildlife are susceptible to this too) are in the water nearby, the current travels through their bodies causing paralysis and even death.
Here is the equation: AC electrical power is supplied to boat shore power systems typically in the range of 15-30 amps …… .6 of an amp of electrical current is enough to stop your heart almost instantly if it travels through your body in an effort to reach ground.
How does this occur: It occurs when, through a wiring fault or a fault with an AC appliance allows stray current to travel through the boats DC ground circuits which include underwater metallic components such as the prop shaft or stern drive. Think of your boat when plugged into shore power as similar to a hair dryer plugged in and floating in the bathtub. This in effect electrifies the water in the immediate vicinity of the affected boat. Anyone swimming nearby can be affected by this as the electrical current moves from the charged water to ground. If you remember your basic electrical theory electricity always moves from the source to ground and if your body gets in the way it will pass right through you and your heart.
Another point that you need to be aware of is that this occurs mostly in fresh water situations, much more so than in salt water. This is because salt water is a better conductor than fresh water and any current dissipates rapidly after it enters the water. In fresh water it remains at a concentrated level in the immediate area surrounding the boat. And when you take into consideration that the high salinity levels of the human body actually make it a better conductor than the water itself, just by being in the water we actually provide the best path for the current to move to ground.
This is a very brief overview on how this can occur and is occurring. I will have much more to say in future posts. For more on this I invite you to visit a couple of websites dedicated to this phenomenon. I will add them to my links page as well.
http://www.electricshockdrowning.org/ This site is operated by Kevin Ritz who has a very deep connection to this issue.
http://www.boatus.com/seaworthy/magazine/2013/july/electric-shock-drowning-explained.asp A very good article by Boat US which offers a very good description on how to inspect for electrical leakage aboard boats.
http://www.boatingmag.com/how-to/electric-shock-drowning-prevention More good information.
Our club race committee boat is a FRP Rosborough 28 which I believe was initially used for lobster fishing in Nova Scotia up until about 1990 when we converted it for use by our club. Over time the aft deck sole which is comprised of plywood sheeting with a fiberglass laminate outer layer has deteriorated due to moisture intrusion from the elements and as a result has weakened considerably to the point where we deemed it unsafe and a repair was necessary.
To that end after the boat was hauled for winter storage last fall we began by shrink wraping the entire boat leaving enough head room to allow for an adequate working space above the aft deck. We also installed a hindged plywood door for easy access. This past week myself and a couple of other members, Mark Backman and Bart Bies began the repair and re-construction of the deck sole.
The first step was to remove the FRP laminate layers from the rotted plywood. To do this we utilized a curcular saw with the blade depth set at approxametly 3/16″ and cut through the laminate layers in the required areas.
Cutting through the FRP layer to separate it from the plywood
After the cuts were made the next step was to searate the FRP outer skin from the rotted plywood panels. For this we untilzed a variety of wrecking an bars and a hammer. Actually due to the deteriorated condition of the plywod that FRP skin came off rather easily. The rotted plywood was removed as well.
Removing the FRP from the plywood.
The plan is to re-used the existing FRP skin over the new plywood after a re-build of the structural components.
After removal of the bad stuff and a thorough clean up this is what we had.
So far this represents about 5 hours of work and the next step will be a re-construct of the transverse sole suports.
More to come.