TAXing Möbius Update Jan 1-15, 2023
Sorry for the delay in posting this update of our Atlantic crossing but …………………….. we made it!!! and that is TAXing as in Trans Atlantic Crossing which was definitely NOT “taxing” as in difficult.
This is a quick and dirty sat view of our crossing.
I’ll provide more details below, but short summary is 2718 Nautical Miles/5033km/3127 miles in 13 days 23 hours.
Zooming all the way out, here is a truly global view of our passage.
That’s a LOT of blue water!
This is our GPS track since leaving Turkey/Greece back on Oct. 31st with 5766 NM/10,678 km/6635 miles
Zooming back in to provide some context of the Caribbean Islands that we will be in for the next few months.
OK, now that you have all that for context, I’ll do my best to provide a summary of the passage and some of the more detail stats that many of you have been waiting for.
When we left off in the last update back on New Year’s eve, we were tied up in the Las Palmas marina on Gran Canarias Island all ready to head out New Year’s Day for our Trans Atlantic crossing.
After going through the check out process New Year’s Day, we headed we cast off the dock lines at 11am and motored out of the well protected bay on the NE corner of Gran Canarias Island and put Las Palmas in what little wake we produce.
Timing worked out great as you can see from the SkyBridge helm station as we we sailed into setting sun and more flat seas.
Passage and Paravanes Overview
As the nautical miles and days ticked by, we got into the typical and predicted Tradewinds that would help propel us across the Atlantic. Wind speeds averaged a bit more than 20 knots and swell averaged a bit more than 3 meters. All downwind sailing with both wind and swell coming from behind us and we had blue skies for almost the entire passage. Following seas are great because we get to surf down them as the pass under the hull and adds a bit to our overall speed.
However, following seas also produce some side to side yawing and rolling that creates what Christine refers to as “corkscrew” type motion as the boat crests the top of the swell and can turn to one side as it surfs down the wave.
It is really difficult to capture this in photos and video that conveys what it is like in person but here is a short video looking back from the Aft Deck to help show a bit better. For reference the top of the AL entry into the Workshop where the White LED light is mounted, is about 3m above the waterline.
This is pretty much the same physics in following seas for any monohull so nothing new to us just not the most comfortable and so we deployed the paravanes in these conditions, learned a lot and developed techniques and rigging to improve their performance and ease of launching, retrieving and clearing.
When not in use, we stow the paravanes upright and tied to the aluminium gate stanchions which worked well. Deploying them is a simple matter of slowing the boat down to under 4kts and then I lower them over the side and into the water.
I use the White nylon retrieval line you can see here connected to aft end of the AL fin. This suspends the Paravane in a vertical position and makes it very easy to raise and lower.
As soon as they are in the water and trailing aft, I can just let go of the retrieval line and the Paravane immediately dives down in an arc the radius of the fixed length Orange/Black Dyneema lines that each Paravane is suspended from the outer end of the A-Frame boom. You can see the White triangle of the Paravane flying through the water about 6m/18ft below the surface.
I shot this short video to try to do a better job of showing how our Paravane rigging works and how they fly along through the water.
I came up with this method of running the White retrieval line through an AL low friction ring embedded into the Orange/Black Paravane lines. These White retrieval lines run slack and if you look at the photos above you can see how they trail out behind the Paravanes so as not to have any effect on the position of the Paravanes until I want to retrieve them.
Christine grabbed this shot from up at the bow looking aft which makes it easy to see how the Paravane lines run off the A-Frame booms on either side.
We have not ever had a boat with active stabilisers so we don’t have any experience to compare the performance to. However I know enough from reading and talking with those who do have active fin stabilisers that they tend to reduce the rolling by about 80-85%. Based on our limited experience with Paravanes so far and in talking with others who have them, the estimate for more like 60-65% reduction. Plus of course each hull and boat is very different in its ride characteristics taking into account hull shape, boat speed, displacement, length, beam and a long list of other factors that determine how any given boat reacts to various sea conditions. Whatever the numbers there is no question in my mind that active stabilisers would reduce the roll more than passive Paravanes and I think we would all take less rolling and motion underway than more. So it becomes a matter of setting expectations and so far for me I have been very pleased with the degree our Paravanes improve the ride. Overall I would say the most accurate description is that they dampen the roll by making it much slower and less number of degrees and we have been very glad to have them as an option to deploy whenever we wish. On this downwind Atlantic crossing I would estimate that we had the paravanes in the water about 60% of the time. By having them in and out multiple times we were also able to get a much better sense of the speed reduction from the drag they produce and this ranged from .5 to 1 knot of overall boat speed.
Atlantic Ocean should be called Sargasso Sea!
A new challenge we literally ran into on this crossing was an enormous “bloom” of Sargasso seaweed that began part way through the first week of the crossing and continued all the way over to the Caribbean. Everywhere you looked all you could see were these yellow/green masses of Sargasso weed and all their “grapes”. Some of these were the size of small lakes and there was no avoiding them, you just held course and went through them. No harm to the boat but over time we started to slow down as these masses of seaweed started to wrap themselves around the Paravane lines.
We evolved a technique for clearing these lines that worked very well. Christine would slow the boat down to about 3-4 knots and I would then hand pull the White retrieval lines through the hand winches on either side. The retrieval line would pull the Paravane into a tail up vertical position and as I kept pulling in a bit more line the Paravane would “pop” up out of the water like you see here.
This would whip the two lines attached to each Paravane as it surfaced and jumped up out of the water and shake off most of the Sargasso. If there was some still remaining, I could quickly repeat the process by letting the retrieval line out until the Paravane dove down in its arc and shed a bit more Sargasso and then pull the line back in until the Paravane popped out of the water again and shook of the remaining Sargasso. Worked very well and the whole process of clearing both sides would take less than five minutes and the Captain would bring us back up to our regular SoG (Speed over Ground) of about 8-9 knots.
There were a few times when we noticed that we did not return to full speed after clearing the lines so we knew that we must have also fouled either the hub of the prop or more likely the top front edge of the rudder where it is close to the hull. When this happened we would stop the boat completely and run in reverse for about 30 seconds and also disengage the clutch so that the CPP prop would come to a full stop and then take the boat back up to speed and continue. First time this happened I dove down off the aft end of the boat by the Swim Ladder with my mask on to confirm that the rudder and prop were clean and clear, which they were, and so we brought the boat back up to speed and continued. This added procedure to clear the prop/rudder was only needed about 3-4 times in the two week passage and the rest of the time we only needed to clear the Paravane lines.
About the only breakage we had on this crossing was a SS shackle that attached the Paravane fixed length line to the outer end of the Starboard/Right boom which meant that we were down to just the one Paravane on the Port side.
In these sea conditions it would have been a bit risky to bring the A-Frame into its vertical stowed position and climb all the way up to replace the shackle with a new one so instead I simply tied a bowline loop into the end of the Dyneema line and was able to climb up on the Arch and loop it over the end of the boom with our long boat hook.
These Dyneema lines I had purchased were made to go on electric winches on the front of off road vehicles and if you look closely (click to enlarge any photo) you will see that they had some very tough reinforced anti chafe tubes wrapped around each which worked out just perfect for my use and no visible chafe by the end of the passage.
That was about the extent of the “excitement” on this passage so I am very happy to not have much else to report. All four of us quickly settled into our rhythm and the 14 days slowly ticked by until we arrived off the SE corner of the French island of Martinique where we anchored off of the small village of St. Anne.
When we left the Canary Islands we thought we were going to head for Grenada but a good friend and long time sailing collegue from Switzerland, Philip, had flown into Martinique for a few weeks of kite foiling and we had not seen him for several years so we changed course to land here in Martinique. I’ll provide more details and photos of this lovely spot in the next update and now go back to providing more details on the passage that many of you have been asking for.
Passage by the Numbers:
Along with many of you, we have been looking forward to compiling some of the real world data of the boat’s performance as we put more and more nautical miles under the keel and more hours on the engine and all the systems. Easy to skip over for those not interested, but below is my summary of the overall performance of Möbius so far. I’ll try to keep it simple and just list all the measurements that I think will provide the best overview. We do everything in metric units but I’ll provide some conversions for US and British as well.
- Total Passage Distance, Las Palmas Gran Canarias to St. Anne Martinique: 2718 nm / 3128 miles / 5034 km
- Total Elapsed Crossing Time: 13 days 23 hours
- Average wind speed & direction: 19kts @ 160 degrees to boat (almost behind)
- Average seas: 0.8M surface waves + 3M Swell @ 165 degrees to boat
- Overall Average boat SoG Speed over Ground: 8.1 kts/hr / 9.3 MPH / 15 Km/Hr
- Average NM per 24 hour day: 195 nm
- Total Diesel Fuel consumed: 5072 L / 1340 USG / 1116 Imp. Gals
- Fuel Consumption @ 8.1 kts: 1.87 L/NM 0.49 USG/NM 2.03 NM/USG
- Gardner engine average RPM on passage: 1448 RPM
- Average Exhaust Gas Temperature EGT: 335 C / 635 F
It is worth noting that all these numbers are actual directly measured units, not estimates or calculations. Fuel totals for example are the sum of every refill of our Day Tank as measured using a sight glass tube. Distances are as measured by our GPS. Elapsed times are from the time we left the dock in Gran Canarias until we arrived at the anchorage in St. Anne Martinique.
To my way of thinking, using such direct measurements throughout the passage and totaled at the end of the total passage time frame and distance provides the most accurate and realistic numbers possible.
Our design goals for Möbius included being able to average 8-9 knots SoG enabling us to cover 200 NM per 24 hour day while burning less than 2 Litres per NM and so we are very happy with these real world numbers. Our sincere appreciation to our brilliant designer and NA, Dennis Harjamaa at Artnautica Yacht Design in Auckland, NZ for designing our hull and boat that met and exceeded all our design goals so well. Thanks Dennis!
I will continue to keep logging all the extensive amounts of measurements for every nautical mile we cover and will update these as the months, years and nautical smiles go by.
Mr. Gee v2 Performance
I’m also delighted to report that Mr. Gee v2 performed flawlessly. We’ve never had a power boat before and so having an engine running 24/7 for two weeks was also a new experience. In total Mr. Gee’s hour meters recorded 337.3 hours and he purred away every one of those hours without a problem. Needless to say we are particularly delighted about that performance figure!
Similarly, our Nogva CPP or Controllable Pitch Propeller and Gearbox also exceeded expectations and performed flawlessly so our overall propulsion choices continue to be one of our best decisions in designing this boat. This propulsion duo has given us a “set it and forget it” kind of combination where we pretty much just set Mr. Gee’s RPM at 1450 and let his governor keep it there, adjusted the Pitch until the EGT was at about 340 degrees C and didn’t need to change it until we put the anchor down in St. Anne two weeks later.
Answering more Questions:
To answer a related question I’ve received a few times about drive line noises and vibrations we might have given that the Gardner engine is directly bolted to the Nogva Gearbox and then a direct connection between the output shaft of the Nogva CPP gearbox and its propeller shaft.
This is in contrast to many boats which have a constant velocity universal joint or CV arrangement in their driveline but this is not possible with a CPP as the pitch adjustment rod needs to travel all the way from inside the gearbox through the center of the prop shaft and back to the hub of the CPP prop.
Instead, the Nogva gearbox input connects to the Gardner crankshaft via a large flexible rubber CentaMax coupling like this.
The loudest engine related noise we have is actually that of the extraction fan which runs at all times and is part of our fire suppression system and this is something I am looking into replacing with a quieter fan. The Gardner itself cannot really be heard at any speed from either helm station. There is no audible sound from any driveline vibrations but if you really focus on it you can feel a slight vibration when we are underway. It is very steady and smooth so not something either Christine or I have noted.
Difficult to know how to measure and better answer this question and I don’t have a similar hull with a fixed prop and CV setup for comparison but I can say that one of the features we have been most impressed with and appreciative is just how quiet Möbius is both underway and at anchor. Indeed one of the most common unsolicited comments we get from our guests and others who come aboard is the almost complete lack of any noises on the boat and just how quiet is is while on board.
However, I too was curious about noise overall and so during the passage I used a sound meter app on my phone to take some readings at various places on Möbius and found the following averages all taken while cruising at 9 knots in 22 knots of following wind and about 3 meter seas:
- Inside Engine Room 80db
- Workshop 73db with ER door open
- Guest Cabin 57db (which shares a bulkhead with the ER)
- Main Salon 55db
- Master Cabin 50db
- Skybridge 58db
- Aft deck 64db
This chart will help make some sense of these db decibel numbers.
As another frame of reference, right now, sitting in the Salon typing this message with the door open while at anchor with about 21 kts of wind outside my sound meter is showing 21.5db
You can draw your own conclusions from these numbers but one of our better decisions was to put in so much EPDM and acoustic panel insulation in Möbius and we appreciate this literally every day we are aboard.
Observations from this Atlantic Crossing
Many people ask about a day in the life when we are on these passages and about our watch schedules. During the daylight hours we are quite informal about our watch schedules and just take turns being on watch and at the helm until we feel like a change and a break. In these mild weather conditions we spend most of our time up in the SkyBridge as it has such great views with its height above the water and 360 degree views all around. We have super comfy helm chairs from Llebroc at both helms which are fully adjustable to recline, change lumbar support and have a good foot rest so spending hours in these is a joy. We are both voracious readers and so we probably spend the most hours reading our wildly diverse range of book genres from romance and murder mysteries to quantum physics.
We find 6 hour night watches work best for us so we tend to have dinner around 6pm and then I start my watch at 19:00 and Christine comes on at about 1am through 07:00 when I get up and take over again. Christine will often go down for a few hours in the morning and then we settle into our relaxing day mostly lounging about and reading.
For me the biggest surprise of the passage was how much I missed the challenges that come from sailing. It is just little things like the satisfaction of adjusting your sail trim and getting a bit better boat speed. The drill you have to go through to adjust or douse sails when you see a squall up ahead and then put them back up after it passes. Or that calm that comes over you when you turn off the key after having to motor for some time and the sounds of just the water on the hull takes over your whole audio spectrum. I just felt a degree less personal satisfaction at the end of the passage having not faced those sailing types of challenges I had for so many years. However this is also the very first passage under power I’ve ever experienced so time will tell how this evolves and what new challenges lay ahead as our world voyage continues.
One thing that did not change was one of the things I have always marveled at and enjoyed about ocean crossings; being alone in the world’s vast ocean expanses for days or weeks on end. Where every one of the horizon’s 360 degrees is nothing but water meeting sky. We saw less than five other boats the entire crossing so we had these vistas all to ourselves and you truly felt blissfully alone. I am so grateful for these experiences where I feel like I am the most insignificant teeny little speck of dust on the planet and yet simultaneously also the most significant bit as I am all the only speck there is. I had that profound joy for almost all of this passage.
At night, the complete lack of any other light sources meant that I once again had night after night of stary stary skies that not even Van Gough could have captured. One interesting difference this time though was that I did become much more aware of the increased number of satellites taking over the night sky so I was glad to have this chance to take in all those stars against such a black background the likes of which I may only see in reduced degrees in the future.
Our timing worked out such that we had a lot of moonshine the whole passage so that was an extra bonus we both enjoyed on our night watches.
As well as our first crossing under power, this was also a first crossing of the Atlantic for both of us and so that felt great to add these experiences to our lists. I think the only other major ocean passage neither of us have done is now the Indonesia and the Indian ocean so we still have those adventures ahead.
Not sure how well I have been able to capture and convey our latest experience but I hope you found parts of it interesting and worth reading. If you have other questions or topics you would like me to cover in future posts please just put those in your comments below and I’ll do my best to cover these in future posts and comments.
We have now been at anchor here in St. Anne for almost two weeks and so stay tuned for an update on that in the next post. Until then, thank you VERY much for your patience with me in providing you this overview of our Atlantic crossing and I look forward to your comments and questions below.