Category Archives: Sailing

Terrapin Electronic upgrade: Part III

Otto Von Helm

Otto is our third crewman.  He steers the boat for us when we are not able to take the helm, for whatever reason.  Otto is a computer that receives input from various sensors and then steers the boat based on criteria set by one of the human crew.  We can tell Otto to steer to a particular compass heading.  We can tell Otto to follow a particular route entered into the Zeus 2 chartplotter.  We can tell Otto to keep the boat at a particular angle to the wind for optimum sailing.  How does Otto do this?  Otto is a B&G NAC2 computer linked to the Zeus 2 MFD via the N2K backbone for the control interface, and a motor that drives the steering wheel via a belt.  Otto receives a variety of data from various sensors also  connected to the N2K backbone.  This includes wind speed/direction, compass heading from the Precision 9 compass, and rudder angle from the rudder angle sensor. 

The Precision 9 compass is the key to allowing Otto to know which direction the boat is pointing.  While we have a great gimballed compass at the helm, it is not electronic and does not provide any information to Otto.  The Precision 9 is a fluxgate compass (electromagnetic) that provides heading and rate-of-turn information to the N2K network for use by the autopilot, radar and other algorithms within the Zeus2.  It has an internal array of solid state sensors that can measure motion and orientation on 9 axes.  So Otto always knows exactly which direction the boat is headed.  To maintain a particular heading, Otto sends a command to the motor to turn the wheel, which is attached by a chain/cable mechanism to the boat’s twin rudders.  However, Otto also needs to know which direction the rudders are pointing: straight ahead, 10 degrees to port, or some other direction.  This is accomplished by a rudder angle sensor that I installed in the stern attached to the rudder control mechanism.  The rudder angle information is then sent to the N2K backbone. Finally, we can also tell Otto to keep the boat at a particular angle relative to the wind.  For this, Otto uses the wind direction information provided by the wind vane at the top of the mast through the N2K network. All of this can be controlled by the autopilot function on the Zeus 2 MFD.    The autopilot is an essential piece of gear for any long distance cruising. It can get very tiring manually steering a course for hours at a time, and generally Otto can do it better.  This allows the helmsman to keep a better watch or attend to other things like sail trim./ 

Terrapin Electronic Upgrade, Part II

I see you, do you see me?

In phase 2 of my electronic system upgrade on Terrapin, I installed a Vesper XB8000 AIS transceiver. Automatic Identification System (AIS) is a means of broadcasting the location and information about a ship using VHF radio frequencies.  It is used world-wide by commercial ships as well as recreational boats, and increasingly, other objects like buoys and personal locator beacons.  However, there are a lot of boats that do not have an AIS transmitter, so you can’t rely on AIS to see all ships in your vicinity.  It is nonetheless useful to see commercial ships and large yachts who typically broadcast AIS. If you want to see other vessels transmitting AIS, you only need a receiver, but if you want others to see you, you need a transceiver.  AIS transmits vessel data such as name, size, type of vessel, speed, heading and the Maritime Mobile Service Identity number (think cell phone number for your boat).  The really cool thing is that a vessel transmitting AIS data shows up as a little triangle on your chartplotter, so you can see exactly where it is relative to your own boat.  If you put the cursor over the boat icon, you will see all the information about the boat.   I was sold on AIS when we chartered a catamaran in the Caribbean that had AIS and I could “see” our friend’s boat from 5 miles away on the chartplotter as we rendezvoused.  The AIS unit is basically a small device that can be mounted out of sight and connected to the N2K backbone with a drop cable.  It also needs to be connected to a VHF antenna, preferably at the top of the mast, and an external GPS antenna.  An AIS transceiver can also share the same VHF antenna as the VHF radio using a splitter.  I chose the Vesper Marine AIS transceiver because it had a great reputation and it also had WiFi, so that the AIS data and N2K data could be transmitted to the WiFi system on Terrapin (See blog post How to Get WiFi on a boat).  The Vesper AIS also has a great anchor watch app that will track the location of the boat during anchoring and alert you if the boat drags anchor.

Because of the importance of GPS for an AIS system, they are designed to have a dedicated input from a GPS “mushroom” antenna located in an outside area with a clear view of the sky.  The vesper came with its own GPS antenna which I mounted on the stern rail and routed the coaxial cable to the inside locker where the AIS device is located. An added benefit is that this GPS antenna became the main GPS source for the Zeus chartplotter as well.  Again, this illustrates the benefit of the N2K system.  Because the AIS unit is attached to N2K, the chartplotter has access to not only the AIS data, but GPS data as well.  The Zeus 2 chartplotter also has it’s own GPS antenna, but it is built into the chartplotter itself which is under the solid fiberglass bimini.  It works, but it is not as sensitive as the dedicated AIS GPS. 

The Vesper VHF splitter is a small device that allows the use of the same mast top VHF antenna for both the VHF radio and the AIS transceiver. It is a powered unit that has several great features and is well worth the expense.  It actually amplifies the AIS signal and improves the sensitivity of the AIS.  It also gives the VHF radio priority and maintains an antenna connection for the VHF radio even when power to the splitter is off.  The splitter also has indicator LEDs that indicate whether the AIS or the VHF is transmitting and a red LED to warn if there is a problem with the antenna circuit.  Hookup was easy.  I removed the VHF antenna cable from the VHF radio and attached it to the Antenna Out on the splitter.  The VHF radio was then attached to the splitter “VHF IN” connector and the AIS unit was attached to the splitter via the “AIS IN” connector.  The splitter than needs to be connected to a 12Vdc source, switched on the same breaker as the AIS unit itself.  This is important because the AIS can be damaged if it tries to transmit without an antenna connected.

Initial configuration of the Vesper XB8000 was a little bit convoluted but not too bad if you follow the directions in the on-line manual.  Basically it involves downloading a configuration utility onto a laptop or ipad and connecting to the Vesper AIS directly with a USB cable.  Once I did this, I was able to update the firmware, and configure the WiFi to connect to the Terrapin WiFi router.  I then installed the Watchmate app on my smartphone and was also able to see AIS data and use a very good anchor watch program.

Last but not least, the AIS unit was easily attached to the N2K network with a short drop cable and tee. When I powered up the Zeus chartplotter I was able to see AIS targets all around my area, very cool!  In the settings menu, the Zeus chartplotter also recognized the GPS antenna connected to the AIS unit and asked which GPS I wanted to use: the Vesper or the Zeus.  For reasons described above, I chose the Vesper GPS. 

The Vesper Marine AIS installed on Terrapin has been working flawlessly now for three seasons. Most boats in my sailing area, south-west Florida, do not have AIS so it is not particularly useful for collision avoidance or tracking other boats.  However, as I cruise in areas with more commercial traffic, I will be glad to be able to see these ships.  I believe there are a lot more recreational vessels that have AIS receivers because many VHF radios now have built-in AIS receivers.  In this case, many more vessels will be able to see me.  In one situation, we were following friends on another boat to one of their favorite anchorages off Boca Grande.  Since they were a power boat, they got ahead of us and we lost sight of each other.  However, they could easily see us on AIS and gave us a few course alterations as we approached. 

Sombrero Reef

The Florida Keys Reef is the only living coral reef in the continental United States and the third largest barrier reef system in the world, after the Great Barrier Reef and the Belize Barrier Reef.  It runs along the seaward side of the Florida Keys and is typically about 3-4 miles from the islands.  Sombrero Reef lies just 4 miles from Boot Key Harbor.  There is a cool lighthouse (one of six along the Florida Keys Reef) sitting on top of the reef and lots of mooring buoys surrounding it.  We can sail right up to the reef and hook onto a buoy for an afternoon of snorkeling right off the boat.

An interesting tidbit is that the government has decided these lighthouses are no longer necessary and will be donating them for free to interested non-profits.  If there are no takers, they will sell them at auction to the general public.  Anyone want to own a lighthouse?

Terrapin tied to a mooring buoy at Sombrero Reef.

Keys Fisheries

One of our favorite restaurants in Marathon is Keys Fisheries.  Keys Fisheries is a seafood restaurant/bar, seafood market, and wholesale fishery.  They supply most of the Florida restaurants with stone crab caught in traps in local waters.  Upstairs is a raw bar that serves fresh stone crab and raw oysters.  Do we look happy?

If at first you don’t succeed….

When I purchased new sails for Terrapin, I also bought a spinnaker.  The spinnaker is used for downwind sailing when the wind is between 90 and 180 degrees off the bow.  Paradoxically dead downwind sailing or “a run” is generally one of the slowest points of sail, mainly because you are relying on your sails to be “pushed” by the wind directly behind them.  Conventional main and jib are not really designed for this.  Instead, conventional sails are designed to be a curved airfoil, like a vertical airplane wing.  The wind passing over the front of the sail provides “forward lift” and propels the boat forward.  In some cases, this can propel the boat faster than the wind speed as in the recent Americas Cup catamarans.  The spinnaker is a large light balloon like sail that catches the maximum amount of wind from behind to improve downwind sailing performance.  It is generally used for light wind of less than 15 knots.

The spinnaker is also somewhat tricky to rig and deploy and I had no experience with them other than reading and watching YouTube videos.  We have been on several stretches of long downwind sailing on Terrapin during our recent cruise to the Keys and have been frustrated with the slow speed.  Finally, one day I decided to test out the new spinnaker.  I think I made every mistake in the book and paid the price.  With Laura at the helm, I went to the bow and pulled the spinnaker out of the bow locker.  It is in a rather large bag and pretty unwieldly.  I hooked it up to a bridle that ran from one bow to the other with a shackle to attach to one of the lower corners of the spinnaker, called the tack.  The other lower corner of the spinnaker is called the clew and is where you attach the sheet that runs to the cockpit on the leeward side and controls the shape of the sail. By adjusting both the bridle position side to side and the sheet, I can control the position of the spinnaker and the amount of “ballooning”, or so goes the theory.  The spinnaker is in a sock about 40’ long and designed to be raised and unfurled in two steps: 1. Attach the head of the sail to the spinnaker halyard and hoist it up to the top of the mast. 2. Pull on another line running from a cuff around the bottom of the sock to the top of the spinnaker and then back down again. Pulling on this line raises the sock and allows the lightweight nylon spinnaker to unfurl and catch the wind.  To douse the spinnaker, you pull the sock back down with the same line.  So, I hooked up the tack and clew and raised the sock on the halyard.  So far so good.  Except that by the time I had done all this, the wind speed had increased to about 15k, gusting to 20.  I should have stopped right there.  Hindsight is 20/20, right?  Well, I raised the sock and all hell broke loose.  The sheet running to the cockpit wasn’t secured and came loose, allowing the spinnaker to flap uncontrollably in the strong wind.  It started to wrap around the forestay where the genoa is rolled up on a roller furler. I had also left the two genoa sheets attached to the genoa and these quickly became tangled with the spinnaker lines.  I tried to bring the sock down but it was jammed.  I spent what seemed like an eternity trying to control this crazy flapping spinnaker, but it was probably about 10 minutes.  I finally went to the mast and lowered the halyard lowering the whole mess to the trampoline.  Exhausted.

Lessons learned:

  • Don’t try to fly the spinnaker in wind stronger than 15 knots, at least until you have plenty of experience.
  • Attach the sheet and tack more securely.
  • Make absolutely sure the sock is free and clear of all lines and on the proper (leeward) side the forestay.
  • Remove the genoa or jib sheets so there is no chance of getting tangled
  • Clear the deck of all stuff, fenders, docklines, etc.
  • Practice with raising the spinnaker at the dock before attempting to use it under sail.

Well, after digesting and re-enacting the scenario in my mind, I finally got the courage to try it again when we were sailing downwind in much lighter wind.  This time it worked perfectly!  What a good feeling to pull up the sock and see this beautiful sail catch the wind and feel the boat accelerate.

Flying the spinnaker on Terrapin

Downwind sailing under spinnaker alone

How about a Second Chance?

Heading north up the west coast of Florida we were planning on stopping for the night in Marco Island, the same place we stopped coming south a few weeks ago.  But then we noticed a small anchorage just south of Marco in a shallow area off Cape Romano.  We decided to give it a try.  Wow, it turned out to be one of our more memorable anchorages.  There is a large exposed sandbar called Second Chance Sandbar.  The area is constantly shifting and we had to maneuver very carefully watching our depth gauge.  We ended up anchoring close to the Second Chance sandbar but we were way out in the middle of a very large bay with gorgeous views 360 degrees.  Second Chance Sandbar turned out to be a “CWA” or Critical Wildlife Area that is a nesting habitat for a variety of seabirds.  The other interesting feature of this area is a group of bizarre looking dome houses out in the water that look like they are right out of a Star Wars movie.  For an interesting read, Google Cape Romano Dome House and read the Wikipedia  page.  They were built in the 1980’s as a vacation residence on a small island, but they have been abandoned since the 90’s and the rising sea level is now taking them back.

Second Chance Sandbar from Google Earth

Cape Romano Dome House

Up close dolphins

We haven’t seen a lot of dolphins on this trip but we finally got a bit of a show one afternoon while anchored off of Chino Island, just off the ICW north of Sanibel Island.  There was a group and they were circling around schools of fish in a typical dolphin feeding behavior.  I grabbed my camera and managed to get a few shots.

OLYMPUS DIGITAL CAMERA

OLYMPUS DIGITAL CAMERA

OLYMPUS DIGITAL CAMERA

OLYMPUS DIGITAL CAMERA

OLYMPUS DIGITAL CAMERA

 

Ding Darling

White Heron

The J. N. “Ding” Darling National Wildlife Refuge is part of the United States National Wildlife Refuge System, located in southwestern Florida, on Sanibel Island in the Gulf of Mexico. It is named for the cartoonist Jay Norwood “Ding” Darling.  You can access it by land from Sanibel Island, but the most extensive part of the refuge is a large expanse of shallow waterways and lagoons which provide habitat for a large number of aquatic birds.  We anchored just off the eastern edge of Sanibel Island and took the dinghy into the maze of canals in about 2 feet of water.  I brought my new Olympus OMD E-M1 Mark II with a 300mm f4 IS Pro lens to try it out for bird photography.  Here are a few examples.

Tricolor Heron

Tricolor Heron

Blue Heron

American White Ibis

April 7

Boot Key to Shark River

The wind was predicted to shift around coming out of the south for the next few days, so we decided this would be a perfect weather window to head back north from the Keys.  It was also a good weather window to head to the Bahamas and our friends Randy and Rose on Contessa Rosa were planning on doing just that.  We wished we were also going to the Bahamas, but we need to get the boat in storage by April 15th or so.  The sail up to Shark River was great.  We had about 15-20 knot winds from our stern and following seas.  We sailed most of the way with our sails “wing on wing” with the main let out to port and the genna to starboard.  The only negative were the bugs in Shark River.  Once the sun went down, we needed to get inside the boat and put screens on all the hatches.

April 3-6

Back Boot Key Harbor

We decided to go back to Boot Key Harbor for a few days and get ready for the sail north to Punta Gorda.  We like Boot Key Harbor a lot: super friendly boating community, mooring balls are reasonable at $18.00 a night, the City Marina has good showers and services, and there are lots of businesses close by, like Publix and West Marine.  I worked on some wiring projects on Terrapin, we went to Sombrero Beach, and we ate some great seafood at Keys Fisheries.