Configuring a Cruising Catamaran for a Transatlantic Crossing

Boat Weight

Many/most cruising catamarans are overloaded – you can check by looking at the sterns and see if they are submerged. Sometimes this is because the owner has added an enormous dinghy with huge engine. But often it is simply years of piling on gadgets, gear, toys, household items and all kinds of interesting stuff. It is fun to be comfortable, but it is more fun to have a responsive boat that does not plow its bows into the back of waves, pitch or drag. Having the sterns submerged can take knots off your top speed and add days or weeks to your passage time, increasing risk of breakdown and exposure to adverse weather changes. Catamarans are typically under-rigged, and when overloaded you get a big, slow boat that is not that fun to sail. So owners start motoring to make time. I specified a single fuel tank to minimize weight, and still had a third of a tank when I got to St Lucia after 17 days at sea. The only reason I used that much is I was having to run an engine five hours a day to charge the batteries – one of my charge controllers failed so I only had half my solar charging capacity. I had not added a wind charger at that point so had to fall back on the engines to charge the battery.

When I designed my Catana, I wanted the lightest possible boat. Catana builds high-performance cruising boats with honeycomb cores to strengthen and lighten the boat. They are not light boats though – out of the mold my boat weighed over 17,000 pounds. With the tall mask and long boom, it was even heavier. The tall mast helped boost the average speed on passage – upwind with the daggerboards half way down, I would average 9.5 knots. The boat sailed flat and was very responsive. I asked Catana to design racing rudders for the boat to improve the steering but they did not address that goal. They were having financial problems at the time and eventually were acquired by another company after I acquired my boat.

Charging

I upgraded the alternators on both engines to the max available for that engine. The Catana had two 40hp Volvos and the hulls are easily pushed, so there was plenty of power to run the alternators and motor at hull speed. Originally I thought I needed to run both engines to get maximum charging, but found during the Atlantic crossing that the output on the second alternator was impacted by the first alternator – I was getting almost zero incremental charge by running the second engine. Once I realized that I would only run one engine at a time – the total charge time was only extended by a small margin.

Because I was often delivering the boat, I set a standard that if the boat speed under sail dropped below four knots, I would start motoring. I found that while I was tempted to run a single engine to minimize fuel consumption, there was more load on the steering, so running both engines actually worked better. This may be a unique aspect of my hull configuration – other multihulls may benefit from motoring with one engine.

I installed four solar panels off the stern davits, which pivot laterally to enable some degree of angle optimization relative to the sun. These were very helpful and we would get a surprising amount of charge out of them, particularly when they were clean, and the boat was anchored so the sun was hitting them. I did find that the shade created by the main and boom would cut down charge effectiveness. More modern solar panels may insulate each cell to avoid that problem.

I did have a problem with my solar panel charge controller, as mentioned above. I would definitely add a charge controller to my spares prior to any offshore passage or extended trip to reduce the amount of engine use to make up for reduced charging capacity.

In the Caribbean I added a wind charger on a pole over the port stern to increase charging capability and add charging redundancy. I did not have any more solar panel failures, but it was comforting having the wind charger available. I did find that the wind charger would vibrate, so installation is critical. The port stern cabin was less attractive for sleeping on windy evenings. The charger we installed had a circuit to reduce blade speed, and also had a “leash” to secure the blades in storm conditions. I would keep the blades secured all the time and then unleash them when we were ready to charge.

Sails

The boat has four sails:

  • Spectra cruising main with three reef points and blocks on each reef point to reduce friction on the reef lines;
  • Heavy jib – suitable for storms. Rigged on the furling headstay.
  • Screatcher – rigged half way out the pole and exiting near the top of the mast, on a furling drum and “soft” headstay so the screatcher can be flaked, folded and rolled with the furling drum attached.
  • Asymmetric spinnaker.

I specified a pin head main instead of a square-top. I had a square top on my racing trimaran, but had to pull the pin holding the top of the main to the mast track in order to get the sailcover on. The main, even in Spectra, on the Catana weighs a couple of hundred pounds, and the headboard is nine feet in the air. So unpinning the square top to flake the main would be risky. I gave up some ultimate performance, but avoided problems with reefing and overloading the headboard cars.

I made two critical mistakes with respect to sails:

  1. I designed the furling screatcher for a max apparent wind of 18 knots. This was too light – because of the large main, I needed a large headsail to balance the boat. The jib was heavily constructed to serve as a heavy weather headsail. It was probably too flat and too heavy, so I wanted to use the screatcher to get more power, particularly in the transition zone around 15 knots of apparent wind. If the wind was at all puffy (e.g., always…) I would take the screatcher down early and rely on the jib. The boat would slow down and pitch more – disappointing. The one time I kept the screatcher up – I was leaving Bonaire late on a trip to the Panama Canal – I was reaching along, throwing a rooster tail off the sterns. BANG! 20 foot rip along the luff of the screatcher. Screatcher was furled and spent the rest of the trip down below.
  2. I specified an asymmetric spinnaker for the catamaran. I was used to an asym on my racing trimaran, and would reach up to get apparent wind and accelerate then round down and blast off. I expected the Catana to respond the same way, which was a big mistake. When we were sailing from the Canaries to St Lucia, I found the boat really wanted to go down wind and did not like reaching up across the 15 foot waves to build apparent wind. The downwind hull would start to bury, the opposite stern would lift and the orientation would be very uncomfortable. The helm would load up and it was hard to head downwind. What I should have had was a symmetric I could tag to each bow. Set the third reef, raise the symmetric and then sail 2,800 miles dead downwind. I could have rigged the asymmetric’s tack to one bow and trimmed off the other bow, but it seemed too much trouble and would have been chaos in a gybe.

When I did rig the spinnaker it was a great experience. The spinnaker was the largest that would fit on the boat, so when it was pulling it would lift the bows and really reduce pitching. If I had ordered a symmetric I am confident I could have cut two days off my transatlantic.

Dinghy and Motor

I had a tiny dinghy with no engine – I love rowing and loved keeping the boat light. For the Atlantic crossing, we rolled up the dinghy and secured it in a bow locker – it was off the stern, so there was no risk of catching a wave in mid-ocean and ripping the dinghy off the davits (or the davits off the boat). When we got to St Lucia, several skippers stopped by and said they saw us stow the dinghy and thought it was a great idea. Off the stern, off the deck – no risk. We also have a liferaft, so we were not increasing our risk in the event of a hole in the hull.

Water

The boat has a watermaker, but the water tastes slightly salty, so we used bottled water for drinking and cooking. Also, I made a habit of only running the watermaker offshore, to avoid drawing sewage into the freshwater system. But there was no guarantee that while the boat was at a repair site someone did not turn on the watermaker by mistake and draw polluted water into the watermaker. I would backflush the system and also installed a UV sterilizer but I always used bottled water. We never had stomach problems onboard.

I had a saltwater footpump installed near the sink with a separate spigot, so I could use saltwater to rinse dishes and reduce freshwater use. This approach worked great and I heartily recommend it.

Spares for Major Passages

My boat was self-contained – I carried everything from port to port as I drew a single line around the world. I did not “cruise” the boat, having a base of operations where I could unload and store extraneous gear un-needed for that trip. So I brought everything with me on every trip.

I will add the list of spares here [TBD].