On Friday Jack telephoned, he happens to be the engineer on the 104 foot 414 ton 6,800 horsepower twin Rolls Royce z-drive ship assist tug Ahbra Franco here in San Francisco; they had a short job to do and Jack knows that I have wanted to see his boat for years now – and today was a perfect opportunity to do so – so he called to invite me along to see the run. So I pedalled over on the bicycle to arrive at the Starlight Marine docks on the Oakland Estuary, arriving early as there was no way the boat would wait for me.
Here’s the picture-story from the afternoon’s run:
Tug Ahbra Franco
This is Jack’s tug, he’s the engineer for Starlight on the boat Ahbra Franco, and I got to ride along for the job. We’re going around to the other side of the terminal and pull a ship off the pier and help rotate it so they can head out. Then we’re going back to the Starlight floating barge dock. (This image is from Starlight’s Ahbra Franco specification sheet)
Galley to port
The galley is on the main deck level, the door aft to the stern winch deck is to the left in the picture. This is a full-size house-style galley, as the crew of four will live and work on the boat for their two weeks on. The tugs will run continuously if needed, so the crew stays with the boat – don’t plan on going home for the evening!
Jack serves up root beer soda
Looking forward from the galley is the passageway forward to stairs going down to the engine room and up to the bridge. Jack is standing directly on top of the engine room. The wood column is a wire raceway from the engine room up to the bridge.
The everything table
If you turn around from the galley you’re at the table. There are four people to run the boat, and this is the table where you eat, do paperwork, sign in the guest log – it’s a popular place.
Pantry to port
Adjacent to the galley is the ship’s pantry, squeezed in beneath the stairs leading up to the bridge. There are a lot of low overheads on the boat, and they are wrapped in pipe insulation to protect your head as one moves about the tug.
Stairs down to engine level
The stairs are steep compared to house stairs, not quite a ladder but close. These are the stairs down to the engine level, and also the cabins.
At the stairway landing are doors to the cabins. Jack’s cabin is directly forward; turn around and there’s a big metal sound-proofed door into the engine room.
Looking back up the stairs
Looking back up the stairs you can see it’s low clearance. The engine room door is to the right.
The cabins are shared between crew; Jack has this cabin for two weeks, and then he’s off duty and his replacement uses it for two weeks – so normally only one of the double-bunks is in use. As the engineer, all of the equipment manuals are on the shelves above his desk.
Turn around in the cabin and there are the bunks. Right now Jack’s gear is in his small black duffel, as he’s headed off the boat and home the next day.
Into the engine room
To get ear muffs we had to go back to the galley (they were at the table). Stepping outside aft thru the big locking metal door we’re on the aft deck, turn left and there’s a stairwell down to the engine room. Lots of metal everywhere, do not fall down the steps!
Cat C-175 engine
This is the starboard Caterpillar C-175 engine; it’s 16 cylinders, weighs in at 28,000 pounds, and generates 3,400 horsepower. Jack mentioned the engine has to get up to 140 degrees internal temperature before you can put it in gear, and with 300 gallons of lubricating oil running through it that temperature rise takes about 30 minutes at idle – so the engines are fired up well before the boat is needed on a job.
Engine in beta test
These engines are new to use on tug boats, and the boat is sending engine data back to Caterpillar in real time through a wireless modem hooked up to all the motor instrumentation. As an example, each injector has a sensor and if anything reads out-of-band an alarm is sounded (quite surprising when you’re on the bridge and the siren goes off) – so they are still working out the kinks.
Fuel flow manifold
There are diesel fuel tanks all over the boat, some 70,000 gallons in total. Jack figured we’d burn 400 gallons on our 3 hour job. They had just taken on 18,000 gallons of fuel earlier and that new fuel was being polished through a set of filters before being placed into the main reservoir tanks (the day tank that actually feeds the engines is 1600 gallons). The fire hose pump is to the left in the photo.
Closeup of the fuel polishing
There’s a lot of piping to move fuel around, and gauges and pumps to move the fuel through filters. One of Jack’s jobs is to keep track of it all – lots of data logging going on in this engine room; every filter change is logged, fuel flow is logged, most things are logged for reference and determining preventative maintenance schedules.
Fire pump setup
This tug is also used for offshore rescue and recovery work – Jack mentioned one job took the boat out 500 miles off the coast to drag somebody back in. The boat carries fire nozzles, one each front and back, and this 250 hp engine powers the circular pump that pushes sea water through to the nozzles.
How to start the fire pump
And just in case you weren’t certain how to start up the pump, there’s a handy sign right there!
The ship runs on generators, not batteries, and to that end there is always a generator running (there are two to choose from). The power is managed in these grey cabinets.
The big generator
Here’s the big open AC generator for tug power. it’s fairly noisy, so Jack prefers to run the quieter generator in the sound-proof box set aft between the main propulsion motors.
The sound-proofed generator
Here’s the generator they prefer to run while at the dock. With this generator running and the doors closed, you can’t even hear that it’s running while upstairs watching a movie on the big screen TV.
Headed back to the propulsion room
Jack is opening the bulkhead door aft to the Z-drive propulsion room. The port side engine shaft alley is visible to the right as the square shiny metal box. The engine shaft rises up above the motor and connects to the ‘Z’ drive located under the aft deck. The engine room uses a CO2 fire suppression system, big tanks of carbon dioxide that floods the area, displacing the oxygen. The tanks are fired from the pilot house and are only fire when all dampers and ventilation is sealed and everybody is out of the engine room.
Port ‘Z’ drive
Now we’re crouched down under the aft deck, where the tops of the ‘Z’ drives are located. The drive shaft goes through a 90 degree gear box and down to the propeller, while simultaneously spinning very large drive belts that power the hydraulic azimuthing pumps through the black hoses. Spare parts are stored outboard in cardboard boxes set on the shelves behind the ‘Z’ drives (a set of spares for each drive).
Starboard ‘Z’ drive
And the other drive. The props are 9 feet in diameter, and have their own 90 degree gear box located under the boat. The props are housed in a metal cylinder or cowling and can be independently rotated 360 degrees, allowing the tug to drive off in any direction, including sideways, at full speed.
Overview of the ‘Z’ drive space
Looking aft from the door into the ‘Z’ drive room, the drives are set port and starboard behind each propulsion engine, the shafts enter and connect to the drives. The place is kept really clean.
Back to the engine room
Now we’re back in the engine room, having just closed the ‘Z’ drive door behind us.
The engineer’s station
Jack is going over to the engineer’s station located in the center of the engine room to check on how things are going with the motors. They have been running for 20 minutes now and are still not quite up to temperature.
Fuel log on the white board
A running log of fuel in each tank is maintained on the little white board. If there’s anything you don’t want to do on a tug, that would be running out of fuel. It’s not like one could run to the gas station and fetch another 5 gallon tin of diesel.
Up on the bridge
This is where all that power is controlled from. Jack’s in the captain’s chair, with the ‘Z’ drive controls located port and starboard. There is no wheel, as there is no rudder; instead, the engine throttle is controlled by the thumb pushing the lever forward or backward, and the propellers angle (azimuth) is controlled by rotating the control.
Microphones all over the place
There are three VHF radios on the bridge, and the captain has microphones suspended above him so he can keep his hands on the engine controls while talking on the radio. There are push-to-talk buttons set on the table right next to the azimuth joy-stick, so he can hit the button with his thumb and lean over towards the microphone for the radio he wants to use.
I got to sit in the chair
I was invited to try out the chair, and was darn careful to not touch anything. The engines are running, though the ‘Z’ drives have not been engaged yet. There is a clutch to the drives, and engaging the clutch is hard on the ‘Z’ drives – they find sheared bits of metal in the ‘Z’ drive cooling oil. So once the drives are engaged they are left engaged until the engines are shut down. To ‘stop’, all one does is point each drive outboard, engage the autopilot, and the boat will simply hover in place.
Lots to look at when operating the boat
There are lots of controls for the tug – forward winch is managed from starboard panel, aft winch from port side , all the engine data is brought up, radars, chart plotters, paper charts, wind speed and direction, depth, and perhaps the most important control – forward winch strain gauge so you can tell how hard you’re pulling.
Overhead panels with buttons as well
There are even more switch and breaker panels located overhead, for things like lighting. Spot light controls are overhead as well, plus an extra VHF radio.
Behind the captain’s chair is another chair and the ‘office’ with the tug computer and chart table, and the boat’s intercom phone. The bridge stairs are to the left in the photo, and when the tug is operating we stand to the left and right behind the captain so we don’t block his view.
Aft deck winch
Looking aft is the rear deck winch and engine dry stack exhausts. This boat as air conditioning and fresh air is drawn into the boat from aft of the pilot house. The slightly smaller Z-Three Starlight tug is tied up just behind us.
Aft deck view without the fisheye lens
A more normal picture of the Starlight tug boat base. I’ve gone past this dock hundreds of times with Tiger Beetle, and it’s fun to see what it looks like from the tug boat’s perspective. We’re 35 feet in the air in the bridge, which provides a completely different view than when 6 feet off the water in Beetle.
Waiting for the engines to warm up
So we’re hanging out, waiting for the engines to come up to temperature. There are four people on the boat for today’s short run. With this boat two captain’s are required to be on board, plus the deck hand/mate to handle the tow line, and the engineer (Jack) to manage the engines.
And now we’re underway, off the dock, and being up in the pilot house is much like being in an office space – it’s quiet, pleasantly warm with the heating/cooling running, and we motor slowly out the Oakland Estuary past the shipping traffic and activity. Our job is in the outer harbor, to pull a ship off the dock and spin it around so they can head to sea.
Cap Palliser being docked
We pass two tugs moving the container ship Cap Palliser into position on the dock. The ship’s now plug-in to the dock when in port, so they do not run their engines. This means the ships have to be placed just-so in order for the power cables to reach shore-power. Jack mentioned that some times they need to adjust ship positions by one foot to get the power cables to reach.
Starlight’s Z-Four working
This is Z-Four, one of the Starlight boats, working away on Cap Palliser. They are working the bow, we will be working the stern when we get to our ship around the other side of the port.
The wake thrown by the tug is very turbulent compared to what I’m used to from Beetle’s motor. We’re spinning two enormous 9 foot diameter propellers down there, and even at low RPM they move an amazing amount of water.
Dave at the helm
When moving, most everybody hangs out on the bridge. Dave is the captain, Rich to the right is the mate and will handle the tow line, and we have two maritime academy students on board to observe. Dave has his hands firmly planted on the ‘Z’ drive controls as we power up the estuary.
San Francisco to port
Rounding the end of the terminal is San Francisco. It’s a grey overcast day and is due to rain tonight. The wind is up, 20 knots or so, and the bar pilot on board the ship has called in a third tug for the move, as he’s concerned about the ship’s windage pushing him over to the shallow mud that the ship needs to negotiate.
There’s not much to do while driving along, the ship is quiet and we’re just tooling along. A great time to talk story. Jack flies out home tomorrow, Dave is looking for a place to have horses, and lots of tug boat goofs are brought up as there are guests on board (like me) that haven’t heard them before.
Our ship is beyond Ever Charming
This is the outer harbor, our ship Mol Competence is aft of Ever Charming and facing the shore (so they did not spin Competence when bringing the boat in to the pier). The mud flats are close by off to the left in the picture.
When we get close to things Dave pays a lot of attention to what’s going on around him. The tug is enormously powerful, so it’s relatively easy to break stuff – such as the pier’s concrete that isn’t designed to handle a tug boat pushing hard on it. He does not like to break things.
High resolution radar
The radar display is mounted outboard of the captain’s left knee where it is easy to glance down and see. The resolution is fantastic when zoomed in like this, he can spot every post and pole and marker in the water. We’re in the center of the display, and that’s a portion of the Bay Bridge to the left.
Hanging out for a bit
Tug Z-Five is already on station when we arrive, and we join up to wait for the ship’s bar pilot to be ready for us. To hang out Dave presses the bow up against one of the rubberized fenders bolted to the concrete pier, points the azimuths outboard and slight aft, leaves the engines in idle, and turns on the autopilot. The boat will hang like this for as long as we want, and we don’t have to risk damage to the ‘Z’ drives by disengaging them. The motors are so quiet you don’t really notice them.
That’s our ship job
Beyond Z-Five is the blue-hulled Mol Competence. They are departing and we’re here to help them out.
Tug no. 3 arrives
Here comes Tug no. 3 to help with the job. Normally only two are used, except this time the wind is up higher than the bar pilot would like. This tug is from AmNav. The tug boat companies share jobs as needed to keep the ships moving, so two tug companies are involved in this move.
We’re the stern tug on this move. The ship’s crew are on the machinery deck, preparing to take our tow line through the chock and to a towing bitt. We’re told via radio that bitt is rated for 74 tons – so Dave notes that down and has to be certain he does not exceed it. He mentions that the older ships are often not equipped to take the strains the newer tugs can deliver. It used to be that 40 tons was all the tug could do, then 50 came along, and now this tug can pull 90. So we watch the strain gauge to make sure we don’t go over 74 tons.
The chock we’re pulling through
The chock is the big, strong (we hope), metal oval welded or bolted to the ship’s deck. The load on the chock can be twice what the load is on the bitt if we pull sideways on the ship. The fellows on the ship are wearing hard hats and ear plugs and safety harnesses and high visibility overalls.
Rich on deck sending up the monkey’s fist
Rich puts on his hard hat and life jacket and heads out to the bow, ready to toss the monkey’s fist up to the ship. The tow line is 4″ diameter spectra and while way lighter than a steel tow line, is way too heavy for a person to throw. The ship crew will pass the monkey’s fist through the chock, and then three of them working together will pull the tow line up and drop the spliced eye over the bitt.
Pulling the monkey’s fist through
Hook up complete
Backing around to the side of the ship
With our line attached, Dave starts to free-spool the forward winch and we back out and around the ship, to set up on the port aft quarter. When going backwards you have to look behind you, and there’s Z-Five moving past us.
Waiting for the bar pilot
Now that we’re connected for the pull, we shift around to the aft quarter and wait for the bar pilot to be ready, perhaps twenty minutes are spent hanging out and telling more stories.
All lined up and ready to go
The two bow tugs are set as well, we’re all pressing up against the ship and holding position. When the bar pilot wants to pull in their dock lines he asks all of the tugs to push ahead low and keep the ship pressed up against the dock. We’re now starting to work.
Pulling off the dock
The first part of the job is to pull the ship off the dock. We’re in a direct pull, with the tow line running straight out from the deck winch, through the ‘U’-shaped staple, and up to the ship’s chock and bitt. Dave listens to the bar pilot’s call on the radio, and he wants everyone to pull straight off the dock.
Coming off the dock
Dave is keeping a strain on the tow line and we’re moving the ship. Our tug is significantly stronger than the two on the bow, so we’re told to not pull as hard in order to keep the ship parallel to the dock as the ship comes out sideways. The bar pilot has spotters fore and aft on the ship to radio positions to the pilot, and the pilot then radios to the tugs on what he wants the tugs to do.
Swinging to pull to starboard
Now that the ship is clear of the dock, the next job is to spin the ship 180 degrees to get the bow pointed towards the bay. We swing sideways and start to pull the stern around to starboard. There’s relatively little room to do this, so Rich is looking out the back of the tug to watch clearance behind us. Of the two tugs at the bow, one is pulling and one is pushing. The bar pilot wants the boat to swing fast before the wind catches it, and asks us to come up to half power.
Watching the strain gauge
Now we start watching our strain gauge. Even with engines at half power there is almost no shaking or movement on the tug, we’re just pulling and there’s no sense we’re pulling hard. So we look at the gauge and it’s already at 34 tons. Dave checks his notes and asks Rich to not let him get over 74 tons, as the bitt might fail at that point.
Now we’re up to 3/4 power and you can finally feel the engines running two decks down on the tug. Jack has gone down to the engine room to keep an eye on things, leaving Rich and Dave on the bridge. (and the backup captain on the tug is down stairs watching TV – he’s seen all this a lot and would rather watch the news).
And pulling harder still
Now we’re getting to loads where Dave gets interested. The max load I saw was 61 tons on the line, the picture shows 51 tons on the gauge, and we’re rumbling a little. We’re still pulling in line with the tow, minimizing load on the staple.
Bow tug working
Then we swing off to the side and go into an indirect pull where we have the tug pointed forward, with the tow line off at 90 degrees to port, and engines opened up to keep strain on the tow line. From here we can see one of the bow tugs, with mast down, pushing on the bow of the ship to swing the bow through. The tugs have to be careful about aerial clearance when working under the ship, as it is possible to get wedged in under the overhanging ship and crunch the mast and bridge – not a good thing to do.
Following the ship out
With the ship rotated, we’re asked to follow along while still attached. The concern is that we’re going to pass alongside the Evergreen ship tied to the pier, and the passing of our ship can suck Evergreen off the dock, so we have to go by very slowly. At slow speeds the Mol Competence has little steerage way, so the tugs are retained to help steer the ship.
The ship’s wake is large, too
The ship’s engine is turned on, and these are direct drive ships – there is no transmission, when the motor starts the propeller turns. The propeller is huge and throws a large, uneven wake at slow speeds. Dave prefers to not get caught up in their wake as it makes his tug difficult to steer. Much easier if you hang slightly off to one side.
A spotter on the starboard mechanical deck
One of the ship’s spotters come over to the starboard mechanical deck door to check on the ship’s position, and radios that information back to the bar pilot. We’re doing fine now, just going slowly and holding the ship in the desired pathway between the mud shoal to starboard and the Evergreen ship to port.
Holding our indirect tow position
We’re still holding off in an indirect tow position, mostly to keep the tug out of the confused water thrown by the ship’s own propeller – which is turning now and pushing the ship forward. The bow tug is holding position, motoring backwards.
Lining up to recover our tow line
Ready to cast off the stern tow line
The bar pilot no longer needs the stern tug, so the ship’s aft crew prepares to drop the tow line back to us. There’s a another group of the ship’s crew up at the bow preparing to do the same thing.
Bringing in the tow
Dave pushes up against the ship’s transom and Rich goes back out on the forward winch deck to recover the tow line. The ship’s crew lifts the eye off the bit and lowers the line back to Rich, and we’re clear of the ship. Rich then carefully lays out the tow line and coils up the monkey’s fist so it’s ready to go. Their next scheduled job is at 4AM in the morning, though other jobs may pop up unexpectedly.
The Mol Competence is headed for sea, we turn and head down the Oakland Estuary for our dock. The whole process took 3-1/2 hours start to finish. The tug will tie up for the night, with Dave, Jack, and Rich sleeping and living on the boat for their two weeks on with Starlight.