Factory boats are rarely ready for an ocean passage. Chet Chauhan explains the modifications he made to his Nautitech Open catamaran
Planning on bluewater cruising? Chet Chauhan shares the modifications and gear he bought before offshore sailing
Bought new from the factory, we knew from the outset we’d have to make a lot of changes to Navasana to prepare her for our transatlantic voyage with the ARC.
I’d previously crossed the Pacific in a Beneteau First 38s5, Sudden Stops Necessary, where I’d made several modifications and fixes along the way.
The factory didn’t offer lithium or big solar options on our new Nautitech 46 Open, and there were some features I wasn’t keen on such as the dinghy davits or the anchor setup.
Finding a broker that could help us make all these modifications aftermarket was critical in our search and was the reason we purchased the boat from Neomarine in La Rochelle.
They could show us boats with solar and lithium installations they’d completed – and we’re glad we went with them as all the work was done to a very high standard.
Powering up for bluewater cruising
Starting with energy, we wanted to be completely green and derive all our energy from solar and wind while we were bluewater cruising.
We built an arch behind the mainsail and while I was concerned it would ruin the look of the boat, the benefits – protecting the tender, more shade, and providing a place to hold onto when getting in and out of the tender– far outweighed any aesthetic drawbacks.
We calculated our energy usage (see panel, below) and estimated we’d use around 330Ah per day at anchor and around 500Ah on passage.
So, 1,200W of solar would work but would be a little tight on passage so we added another 880W of flexible Sunpower panels after we left the Med to make it a total of 2080W of solar.
We went with 800Ah of lithium batteries to tide us over on cloudy days. We also wanted a large inverter to power AC appliances so we went for a 3,000W inverter.
Here are the aftermarket components we installed with the help of Neomarine:
- Rigid Sunpower solar panels 3x395W on support behind the roof plus dedicated MPPT 100/50 controllers for each panel
- Flexible Sunpower solar panels 8x110W on the roof with four on each side in series with a dedicated 100/30 Victron MPPT
- Victron lithium batteries (4x200Ah) with Cerbo GX control
- Victron Multi Plus 12/3000W/120A (battery charger 120Ah and inverter 3,000W)
- Nautitech’s existing standard 2x115A/12V alternators were wired into the lithium setup
Sails and rigging for bluewater cruising
For sails we went with the standard Dacron main and jib but we added a big 95m2 Code 0 65 (Code with 65% mid girth) from North Sails for reaching in light air in the Med and also a Oxley Levante Parasailor for sailing deeper angles in light airs.
We took the electrical winch option on the starboard side to help with getting the mainsail and dinghy up and also installed Magic Marine rope bags which fit perfectly in the space available and were big enough to store all the lines.
Rope bags are better than coiling halyards since the latter introduces twist, which can prevent the sail from coming down.
Here is the full list of options and upgrades:
- Full batten mainsail (three reef lines), Dacron (Nautitech)
- Self-tacking Solent in Dacron, including UV protection strip (Nautitech)
- North Sails Code 0
- Oxley Levante 17.50 and 17 Twinlinesnuffer plus snuffer bag
- Electrical starboard winch in cockpit (Nautitech)
- Magic Marine rope bags
- 12mm Dyneema main halyard
- Dyneema cover on spin halyard and boom mainsheet strop
- Preventer led back through clutches to the winches
We went with the standard twin Volvo Penta 40hp engines (one in each hull) but made a few upgrades.
We added rope cutters to the folding props and upgraded the fuel filters to have a clear bowl to easily see how much water or dirt was in the filter.
Here is the full list of engine upgrades:
- Volvo folding props (Nautitech)
- Ropecutters on props
- Racor fuel filter system
- MDI box shunt to be able to start the engine if the MDI box failed
For navigation instruments we went with the advanced pack option to have bigger screens (for my old eyes).
We also made a few aftermarket changes including adding a wireless autopilot controller and a B&G forward facing camera on the mast to aid with close quarters manoeuvring.
We also installed a duplicate L&S autopilot drive and rudder sensor on the starboard rudder quadrant with a switch between port and starboard drives.
These are the only moving parts that can wear in the autopilot system so we figured we just have a backup for this and not the whole autopilot system including the computer, compass and controller to save cost.
In future we could add these additional components with a separate NMEA backbone for a complete backup.
Here’s the full list of upgrades:
- Advanced B&G Navigation pack including 12in chartplotter and Forward Scan (Nautitech)
- Backup secondary B&G NAC-autopilot drive and rudder sensor
- B&G NAIS AIS transmitter (Nautitech)
- B&G HALO + radar antenna (Nautitech)
- Masthead tricolour Hella LED
- B&G forward camera installed on mast under radar dome
- B&G wireless autopilot controller
- iPad Pro for Nav Tablet
- Navionics charts
- Astra III B sextant
- Weems & Plath barometer
Comms and weather
For the Mediterranean, we installed a 5G router with four external antennas to boost cellular signals up to 30 miles offshore.
We were able to get 140GB for r40 a month, which was perfect for our needs – including the ability to watch Netflix and Prime Video on a regular basis.
The router we chose also works across European, Caribbean and Asian cellular networks.
For weather and email offshore we went with Iridium GO! but installed an external antenna above the radar dome on the mast.
For the Caribbean and beyond we also got the Starlink RV satellite communications system since cellular data is more expensive.
Here is the full list of upgrades:
- Peplink Mobility 5G 4X + 2X Wi-Fi outdoor antenna and Global 5G Router
- Iridium GO! with external antenna
- Handheld VHF with DSC
- Predictwind subscription
- Starlink RV
We completely revamped the anchor setup on Navasana.
On my previous half circumnavigation I had a Rocna which held fast through 40-knot gales so I wanted the same.
Unfortunately, however, only a 25kg Rocna would fit in the anchor compartment, so we ended up going with an oversized 30kg Spade based on the great reviews by Panope and other sources.
We also added 80m of high test 10mm chain.
While I had 100m on my half circumnavigation I only used the full 100m once in the Marquesas.
So, to save weight we went with a little less, at 80m which I could always lengthen with rode if necessary.
We also made a custom harness to stow the bridle away inside the anchor compartment.
Here is the full list of anchoring upgrades:
- Spade 30kg with 80m of high test 10mm chain and an Osculati swivel
- Fortress FX-55 with 10m chain and 50m rode
- Chain counter and remote control at helm station (Nautitech)
- Custom bridle and chain hook
- Custom bridle harness
- Bridle protective tubing on bowsprit bobstays
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We didn’t like the standard davits that came with the boat because of reduced visibility and the complexity of all the moving parts.
We were given a small refund from Nautitech to forgo the standard davits and installed fixed davits which were on the older models of the 46 Open.
Another advantage of our system is that we can also store the stand-up paddleboards on the davits. Win, win!
We went with the biggest tender we could fit and added dinghy wheels.
We also bought a Mantus dinghy anchor, which is the best anchor that I find to hold the dinghy in strong wind and waves.
Here is the full list of upgrades:
- Highfield 340 Classic tender with 15hp Honda outboard
- Dinghy wheels
- Fixed davits system
- Mantus dinghy anchor
For water we went with a large 105lt watermaker and added a Acuva UV filter for drinking water to kill any bacteria/viruses as we didn’t want the hassle of adding chlorine every time we made water.
We also installed a high pressure washdown pump with connectors in the cockpit and the anchor well for washing down with either fresh water or sea water.
Here is the full list of upgrades:
- Watermaker 12V Aquabase 105lt + automatic flushing and remote control
- Drinking water purified using Acuva ArrowMax 2.0
- Hot water heater wired to the inverter with timer
- Freshwater and seawater switchable washdown pump with connectors in the cockpit and anchor locker
- Daewoo mini washing machine
- 2x electric fresh water heads and one manual/sea water for emergencies (Nautitech)
We added a larger 85lt fridge in the cockpit mainly for cold drinks and water.
Here is the full list of upgrades
- Two-drawer fridge upgrade (Nautitech)
- Extra 85lt fridge in cockpit
- Thermomix for cooking using electricity
- Microwave (Nautitech)
We chose a bunch of comfort options from Nautitech, including all the sunscreens they offered.
We also liked the look of teak in the cockpit so went with the teak table option but opted to go for aftermarket Flexiteek for the sole.
Here is the full list of upgrades:
- Flexiteek in cockpit and aft platforms
- Teak cockpit table (Nautitech)
- Cushions for cockpit seats and aft bench (Nautitech)
- Frontdeck lounge cushions (Nautitech)
- Indirect Indoor lighting (Nautitech)
- Saloon table lounge conversion for night watches (Nautitech)
- Sun shades for saloon windscreen and cockpit enclosure (Nautitech)
- Full cockpit enclosure (Nautitech)
- Nesling sun shades for trampoline area
- Upgrade comfort mattress (Nautitech)
- Two wooden deckchairs for the cockpit
For safety we followed the World Cruising Club recommendations for ocean passages, including the ARC, but added a mini scuba tank and compressor to help with a fouled anchor or replacing anodes on the propeller.
The liferaft is in a special compartment that opens from the bottom.
Here is a summary of the safety add-ons:
- Seasafe Prolight six-person liferaft
- OceanSignal EPIRB PRO
- Lifebuoy with inflatable Danbuoy
- Rescue sling and rescue line
- Spinlock Deckvest D lifejackets
- Personal MOB AIS for all lifejackets
- Wichard jacklines
- Radar reflector
- Mini Scuba gear
- Emergency watermaker
- Coppercoat antifouling – since we didn’t want to haul-out every year while bluewater cruising (Nautitech)
- Aft corner bumpers (protects the corners when using the engines to pivot off the dock)
- Plastimo inflatable passerelle
- Folding bikes stored in the engine compartments
- Projector instead of TV that projects onto the cockpit sunshades
- Handheld vacuum cleaner and a big wet/dry vac (which we rarely use)
- Large Dyson fans
- Battery powered motion detector for security
Hopefully this will be of some help if you’re fitting out your own boat for an ocean passage.
You can follow our adventures on our blog sailingnavasana.com and we’ll update you with our equipment reviews once we’ve got 5,000 miles under our keels.
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