Hylas 54 Specifications | Home (Back to home page of website www.Dakare.com)
Electrical Protection
Isolation Transformer with Booster
The Isolation Transformer can be seen inside the Cabinet located in the main stateroom
Ward Marine Electronics ACME 15KVA Isolation transformer with multiple taps - Provides protected 110/220 Volt 50 Amp service
Isolation transformer protection has provided us with peace of mind: (See article in Ocean Navigator on Isolation Transformers - Issue 120 March/April 2002 - by Steve D'Antonio)
All AC current is supplied through an isolation transformer located between main breaker (Aft port lazarette) into the boat and the main switch-panel at the Nav StationThe transformer should be marine rated and large enough to supply all circuits used on board. In. our case that is 50Amp Service at 220V which requires at a minimum a 12KV unit. The closest we could find is 15KV, which provides some overhead.
If neither secondary wires (ship side of transformer) are grounded to Common Ground Point, all circuit breakers are ganged, double-pole type
Shore safety-ground (green or bare) connected to isolation transformer case only
Ship's safety-ground (green or bare) connected to Common Ground Point
No connection from shore safety-ground to Common Ground Point (test at 120 VAC)
The connection from shore safety-ground to ship's ground can allow stray current corrosion. This connection is safely avoided only with complete GFCI protection or an isolation transformer system. Dakare, in addition to the isolation transformer and GFCI at the main breaker into the boat (Aft Port Lazarette), is outfitted with an Galvanic Isolator for ultimate corrosion protection.
Although GFCIs are not required with a correctly operating isolation transformer they have been added on Dakare as protection against the possibility of a malfunctioning transformer (which we have never experienced.)
We have used this isolation transformer successfully in all the countries we have visited. With this transformer, we had the necessary and effective isolation from shore power problems that we have seen plague many cruisers once they left US waters. We highly recommend this device for all those traveling to foreign countries. It has been trouble free and the boost circuit, allowing us to compensate for undervoltage power, so typical of 3rd world and European marinas, has helped to protect our equipment by ensuring that everything is running at the proper input voltage. This is even more critical when running 60Hz equipment on 50Hz. One note, although not true of all European marinas, the preponderance of AC dockside power is limited to 16 Amps at 220V at 50Hz. (With that said, note that in Europe it is likely that no matter how many different Euro shoreside connectors you have - collected from all the previous marinas visited, it is likely that you will still need a new type at the next marina.)
When switching on the power through the isolation transformer, particularly since it was sized to handle 15KV, we have from time to time, experienced dockside circuit breaker interruptions. We have traced this phenomena down to the fact that since the current draw of the isolation transformer is large when first energized due to the size of the magnet coils, an instantaneous power surge in excess of 16 amps may occur which will then trip the dockside circuit breaker. We have found that this is not a problem. We may need to reset the dockside circuit breaker 2 or 3 times. Once done, the initial changing current draw is eliminated and there are no other problems. If the dockside circuits were fused to a higher level (we have not seen this happen with dockside breakers rated at 22 Amps) the initial tripping would likely not occur at all.
Heat dissipation for this isolator is important. We have the transformer mounted on a offsetted fireproof backing and the locker itself is ventilated with fans.
Over Voltage Protection
When we connect into shoreside power, we (and all the other boats) are subject to the vagaries of voltage fluctuations. The likely scenario is that the voltage fluctuation is on the low side. Our transformer has a booster switch to handle that problem. A completely different issue is when the voltage goes high. This can harm all sorts of equipment. On Old Dakare (Our Slocum 43) we lost several pieces of equipment and our inverter when the shoreside power fluctuated very high. Over voltaging can cause fires on board if not properly dealt with. After seeing smoke emanating out of a boat at our dock in Turkey, we found that the fire was caused by overvoltage from the marina. New Dakare never had a problem even though we were a few boats down from the boat that did - which was the good news for us. Pauli, on S/Y Sejner, proposed using a high voltage shorting capacitor to protect all boats at the pedestal connection. It was a simple and effective way to protect the boat. The capacitor is wired between the hot and neutral leads in the dockside plug. If the voltage goes above the preset voltage limit, the capacitor short circuits in the plug and causes the pedestal circuit breaker to trip, saving the boat electronics from the dangerous voltage levels.
The capacitor is: V 275K20
Galvanic Isolation
Galvanic Quicksilver Ignition Protected galvanic Isolator
Model 18478 A3
120/240 V, 50/60 Hz, 50 Amps
Hylas yachts, at least at the time of our purchase, did not come with an installed galvanic isolator. We had a properly sized isolator installed by Wards in Ft. Lauderdale during commissioning. There have been no problems with this device.
Zinc Corrosion Controller, Galvanic Testing and Monitoring
Deluxe Corrosion Controller
805 644-1886
Installed. We usually disconnect and reconnect this device after hauling the boat. Long term usage requires that the underwater anode be spotlessly clean. The only time we feel that this is the case is when we relaunch. If it is dirty with growth, false readings are obtained. Once the galvanic current is tested and found within limits, it is unlikely to change until the zincs are worn out or replaced. After monitoring the boat for 5 years, we believe beyond a doubt that Dakare has no corrosion problems. Another note: When connected, the galvanic current is routed through the testing device. This seems to cause the cone prop zinc to wear faster.
In our case, we had Wards (ABYC Electrical Certified Specialists) in Ft. Lauderdale test the boat for leakage currents and found that the boat was overprotected. This is both good and bad. Overprotected indicates that there is too much zinc and there is a risk of paint blistering around the zincs. In fact, after being in the water for about 4 months, when hauled, there was noticeable paint blistering totally attributable to being overprotected. Also, we strongly believe that the poor state of electrical wiring at Summerfield's also exacerbated the issue. It was felt that a substantial reduction in zinc was required but no one could "guesstimate" how much zinc reduction was required. Summerfield's recommended that we consider putting on a Corrosion Controller unit that would allow us to "dial" in the proper amount of virtual zinc. We concurred and the unit was put on Dakare.
However, several issues ensued. As in most boats, there was a concern regarding the electrical bonding of the rudder to the boat as was the drive shaft and propeller. Engine ground was not considered to be a "proper" ground for the drive shaft. This could be solved by including a shaft wiper that brought ground directly to the drive shaft/prop. No suitable solution could be found for the rudder.
The constraint on using the Corrosion Controller system is that to effectively monitor and adjust the amount of "virtual" zinc the boat sees, one must electrically connect all zincs to the controller unit. The best way to do this is to have one zinc tied in with controller and to remove all others. This is not practical for reasons identified above. The rudder must be protected and the Max Prop should be protected as well since a shaft brush can not guarantee full/perfect electrical contact. Thus, there were 3 zinc systems employed. One for the controller, one for the prop and one for the rudder.
With the system set up according to specs, we found that the boat went from an overprotected state to an underprotected state. By using the controller unit we could dial in the proper amount of protection. This amounted to 550 ma on the controller's gauge. We could achieve that setting if we left the controller at the max setting for underprotected.
After 5 - 6 months of cruising up to New England and back to Florida, we found that the zincs were mostly gone and that there was some corrosion of the prop. This necessitated sending the prop back to the manufacturer. Technical discussions about our experiences led to the following recommendations by the manufacturer. Paint blistering typically does not occur for boats with meter readings less than 700 -750 ma. They suggested that we add more zinc to the boats protection. The table below shows the transitions:
Zinc Inventory & Transition Table
|
As Delivered
1/15
|
As first modified
5/15
|
As recommended
10/30
|
Final Config
|
Spares
March 2006
|
Shaft Zincs
|
(2) 1.75 " ID
|
None
|
(1) 1.75" ID
|
(1) 1.75" ID
|
3
|
Strut Zincs
|
(2) Circular R3
|
None
|
None
|
None
|
|
Skeg Zincs
|
(2) Circular R3
|
(2) Circular R2
|
(2) Circular R3
|
(2) Circular R3
|
4
|
Reefer System
|
None
|
None
|
None
|
None
|
None Required
|
Yanmar Engine
|
None
|
None
|
None
|
None
|
None Required
|
Kohler Genset
|
(1) Pencil Zinc
|
|
(1) Pencil Zinc
|
(1) Pencil Zinc
|
12
|
Water Maker
|
None
|
None
|
None
|
None
|
None Required
|
Max Prop VP Prop Zinc
|
1 (100mm)
|
1 (100mm)
|
1 (100mm)
|
1 (100mm)
|
5
|
Vetus Bow Thruster
(160 KGF)
|
BP195
|
|
BP195
|
(1) BP195
|
4
|
Corrosion Controller
|
None
|
Installed
|
Installed
|
Usually Disconnected
|
None Required
|
We will need to wait to see if\ the new configuration will solve the problems. Somewhere along the line a barnacle formed on the tip of the controller's detector and this inhibited our getting good readings while up North. Every attempt will be made to keep the detector free of detritus this time around and hopefully we will have better luck. This section will be updated in about 6 -12 months to reflect our new findings.
Update: 5 Years after Commissioning - We believe that the Galvanic leakage current is in the proper range. We now get better than one year on our zincs and have not seen any detectable corrosion of the prop or other metallic surfaces.
Lightening Protection
Seral things were done to minimize the possibility of being struck by lightning and in the event that we were, to minimize the potential damage:
1) Extra Heavy Duty 00 gauge wire was run from main shrouds to ground system for lightning protection in addition to Queen Long's standard grounding system. This gounding wire is connected to all ship's through hulls and engine block. If effect, it is tied into the Ship's DC ground. Becuase of the diameter of the wire used in comparison to that used and discussed in the next point (#2 below), it is in effect, quasi-isolated in that the current should choose to follow the path in #2 below.
2) A special (Additional) heavy duty grounding wire was run from the bottom of the mast to the especially equippped DC / AC Lightning Plate shown below to optimize the passing of current to the grounding protector plate. Great care was taken to ensure that the run was minimal and had no bends further ensuring the likelhood that the easiest path for the lightning would be to the protection plate and not elsewhere in the boat. This ground is isolated from the ship's DC ground
Lightning plate grooved with HF dissipating edges. Purchased from Ward Electronics, Ft. Lauderdale
This item is highly recommended
3) Protection Plate not only directs the DC component of a lightening strike to the sea, but because it has maximum edge surface, unlike a standard copper plate, it can dissipate a greater amount of AC current in the lightning strike. It is the AC current that is responsible for much of the electronic instrumentation damage. Without being able to effectively dissipate the AC component of the lightning strike, the AC component can cause a great deal of harm to electronics.
Dissipative Lightning Protection
Dakare has installed on the top of our mast a bottle brush type dissapator which is claimed to help diffuse the likelyhood of a lightening strike. Sister ships of Dakare have been struck by lightning - Dakare has not. Whether or not this is just good luck is impossible to say, but as long as we are not struck, we can attribute some of the protection to the dissapator. This unit is effectively tied into the protection plate discussed above through the mast.
Radio Ground
Following the general practice of isolating the various grounds to be found on board sailing vessels, the radio ground has been isolated from the other grounds. In addition, every attempt has been made to create the best possible radio ground that can be found on any boat. This includes the use of copper mesh imbedded in the hull, the use of separate Dynaplates Grounding Plates located as close as possible to both the SSB radio and the tuner and the inclusion of full length grounding straps located on both port and starboard hulls.
3" flat copper straps running fore and aft on both port and starboard sides of the hull at water level (in addition to Queen Long mounted 1" copper wire)100 Sq. Ft Copper Ground Mesh built into stern hull
Large Dynaplate located directly below tuner and connected to tuner via 3" flat copper wire
Large Dynaplate located directly below SSB Radio and connected to radio via 3"flat copper wire
Zinc Corrosion Controller, Testing and Monitoring
