Last week in the post called How & Why do we make all our Decisions on Designing, Building and outfitting XPM78-01 Möbius? I covered how we developed and use our set of four founding or first principles to base all our decisions upon. We refer to these four pillars as SCEM which stands for Safety, Comfort, Efficiency and Maintenance (lack of).
We don’t use SCEM as filters per se, we use them to keep us on track, keep our priorities straight, by reminding us of what our fundamental values are for this boat. When doing our due diligence and research on some potential piece of equipment It is all too easy to get attracted or distracted by things like cool features or just the sheer number of choices and so as we go through our decision making we are constantly circling back through SCEM to make sure these fundamental requirements are being met.
This week in this Part 2 of our decision making process, I will do my best to summarize the more specific criteria we use to ultimately make our final decisions upon. I will cover this as a series of the following questions that we ask and answer to our satisfaction at least, as we evaluate each bit of kit and then use these to make our call.
- What problem is this item attempting to solve?
- Is the problem/item a want or a need?
- Consequences of adding this item? Domino effect?
- Does it pass the Goldilocks test?
- New vs Tried & True?
What problem is this item attempting to solve?
Might sound like a silly question at first but it is surprising how often answering this question provides the most help in in our evaluation of a design decision or of a given piece of equipment. Let me use our decision of what battery type to use for our House Battery Bank to illustrate but one example of how valuable this question was.
To put this question into context, keep in mind that Möbius is a completely Battery Based Boat, meaning that ALL of our onboard electrical power comes from our House Battery Bank and therefore this is one of THE most critical systems on the boat and one that in some cases our lives can depend upon. For an XPM or any true eXpedition boat that is going to be able to carry us safely and comfortably to locations across the full spectrum of eXtremes of climate and remoteness, we need to be as self sufficient as possible and so our onboard electrical power rates right up there alongside diesel fuel and fresh (potable) water as a critical requirement. An XPM type boat is designed to spend the majority of its time at anchor or at sea, in our case often for months at a time, so in all our design and equipment decisions, we assume that we will have no shore based resources such as shore power, stores, shipping, airports, etc..
Finally, for a bit more context, let me add that we have also chosen to not have an independent generator onboard so ALL of our four voltages, 12 & 24 Volt DC and 120 & 230 Volt AC, come from our House Battery Bank. Most of the time we keep our batteries charged via our 4.48kW array of 14 320W Solar Panels and when underway we have 12-14kW available from the two eXtremely robust 250A @ 28V Electrodyne alternators which Mr. Gee keeps spinning.
One of the very first decisions we needed to make to chose our batteries was what type or chemistry of batteries would be the Goldilocks just right, just for us House Batteries? I’m not going to go over this in any detail here but these are the five battery types we had to chose from:
- FLA; Flooded Lead Acid
- AGM: Absorbed Glass Matt
- Carbon Foam
Many of you and others we talked to, thought for sure that the choice was obvious; go with Lithium and we did consider them, and all the other types, very thoroughly. But it was that question of “What problem is this trying to solve” that made it clear that Lithium was not the best choice for us and that’s the story I’d like to elaborate on here a bit.
Our battery decision making started at the very beginning of our design process, around 2016, and in some ways we designed and built the boat around the House Batteries. For the first few years, we thought we would go with GEL based OPzV batteries such as this one.
These OPxV type batteries are eXtremely robust and often referred to as “traction batteries” as they are used in things like all electric forklifts in warehouses so they had good cycle life and good resistance to sulfation and other features that wold make them a good choice for Möbius.
During this time we were reading more and more about Lithium batteries and we were seeing more and more people who were choosing to go with them so we also spent a good bit of time researching the various types and makes of Lithium, primarily LiFePO4 or Lithium Iron. This relatively new type of battery was said to have a lot of amazing features with the top ones being longer lasting (more cycle life), ability to accept much higher charging rates thus take less time to charge, but perhaps the biggest feature was their much higher energy density. This means that you get much more usable Watts from the same amount of space and weight compared to what you would get from other battery types. Said another way, you could get the same amount of energy out of a much smaller size and lighter battery bank.
As the months and years went by, these claims were validated more and more and we saw the steady increase of Lithium Iron being the batteries of choice for more and more boats so it seemed like the choice was clear right? However when we applied our criteria and use case and asked the “What problem is Lithium trying to solve?” question, we realized that we didn’t have the same “problems” as most of these other boats such as size and weight of our House Batteries.
My earlier comment that we had designed the boat around our House Battery Bank is not that far off as we had designed the hull to take maximum advantage of the characteristics of our original consideration of OPzV batteries which were very large and very heavy. Each OPzV 2/4V cell measured 215mm/8.5” Wide x 277mm/10.9” Deep x 855mm/33.6” High and weighed 110kg/242lbs each, and we needed 24 of these!
As we often do, we turned this “bug” into a feature and built four large battery compartments into the framing of the bottom of the hull such that each compartment straddled the 25mm thick x 350mm high keel bar running down the centerline of the hull. By positioning these battery compartments on the very bottom and center of the hull, we effectively turned the lead in our batteries into a proxy for some of the lead ballast we needed. This is a photo from last year of one of our four battery compartments.
The point here if you are following along with me is that for the use case and design of an XPM, the “problem” that Lithium batteries would solve with their high energy density for a given weight and size just wasn’t a problem we had; we had the room and we wanted the weight. So the search for our Goldilocks batteries continued.
For awhile we continued to think that OPzV Gel batteries were the best fit for us, however, just as we had been following the developments of Lithium batteries we had also been tracking the growing use of Carbon Foam type batteries from FireFly.
They ticked all the boxes on our list of criteria, most notably these were proving to be eXtremely robust and several attempts by test labs trying to purposely destroy these batteries failed and they proved to be almost indestructible which is a huge factor for us and our use case.
These Carbon Foam batteries are also able to work and charge in much lower temperatures such as those we expect to have when we are in polar regions of the world and they are one of the only battery types that don’t suffer from sulfation. and are happy, even recommended, to stay at Partial State of Charge for long periods of time which would normally be the death of most other batteries.
Near the end I found real world installations of these batteries, some of which had been in place for more than ten years and so just before placing this large order of batterie we changed and ordered 24 of these 4V L15+ size Micro Carbon Foam batteries which now make up our 43.2kW House Bank (1800Ah @ 24V) made by FireFly and they have been working flawlessly for the past six months.
Let me be clear that I am NOT saying that Lithium batteries are not a great choice for many boats, nor am I saying that Carbon Foam batteries are “the best”, I am just hoping to explain how and why we made our decision to go with Carbon Foam and why they are the Goldilocks just right, just for us choice. All thanks in part to the question we regularly ask near the beginning of our decision making process; What problem is this trying to solve?
Is the problem/item a want or a need?
We often put each item we are trying to decide on into either the Need to Have or Wish/Want to Have category. Pretty self explanatory I think, Need to Have are items that we feel are mandatory must haves in order for us to feel confident in going to sea and living full time aboard Möbius. Examples for us include things like;
- our high output watermaker,
- Furuno Radar and other navigation equipment,
- eXtremely high amounts of acoustic & audio insulation,
- comfortable Helm Chairs,
- that little FLIR One thermal camera I used to find the overheated wiring a few weeks ago,
- great HVAC systems
- Global communication capability (right now via our Iridium GO)
- and items like this.
The Want/Wish to Have category can be subdivided into groups such as;
- buy as soon as the budget allows
- later when it is ready for real world use (ours)
- nice to have, perhaps a gift to ourselves or each other
Current examples on our Wish/Want list includes things like:
- second Furuno Radar with NXT technology,
- forward facing sonar when it is has been in more mainstream use and is robust enough for our use case
- active stabilization, most likely Magnus Effect type
- kite sail with autopilot to add to our propulsion and reduce fuel usage
- Portland Pudgy, Christine’s long time wish for a small, light sailing dingy
- affordable high speed internet such as that being promised by 5G and satellite based systems being developed.
We also have a third category worth mentioning which is the Don’t Want Onboard category which is sometimes the best choice. Items on this list would include things like;
- anything that requires propane (too much of a pain to fill around the world)
- anything that requires gasoline (too short a shelf life these days)
Consequences of adding this item?
As a good friend and fellow world sailor likes to say “Everything needs” and so we spend time trying to imagine what the needs and other consequences will be if we add this bit of kit to Möbius. Our primary prioritization of Maintenance, lack thereof, would factor into this for example and hence decisions such as;
- no paint/wood/SS on the exterior,
- being single fuel boat with no propane or gasoline,
- no generator
but it could also be other consequences of adding this item to our boat. An XPM is complex by virtue of needing to be so self contained and as we often say Möbius is like a floating village in that we have to look after making all our own water, all our own energy, dealing with all our own waste and so on, but we do strive to apply the KISS or Keep It Simple & Safe philosophy to all our decisions by finding the simplest solution possible. Examples of this would include:
- manual roll attenuation with our fully mechanical/manual Paravane A-Frames
- manual Tender Davit system vs hydraulic
- Gardner engine (no turbo, no electrics, low revs, etc.)
The Domino Effect is perhaps a branch of the consideration of the Consequences of any decision as I just outlined above and is when the result of a decision has follow on effects to other systems on that boat. This can work both ways; sometimes these dominos are positive ones and in other cases they are negative or undesirable consequences. For example, installing the eXtreme amount of EPDM and acoustic insulation throughout the boat has a domino effect;
- stabilizes the interior temperatures and makes them more temperate in both very hot and very cold climates
- this reduces the energy required to cool/heat the boat
- this allows us to install smaller capacity and less expensive HVAC systems such as Air Conditioning and heating
- this lowers the demand on our House Batteries and HVAC systems so they run with less loads and last longer
An example of when the Domino Effect can work the opposite direction might be the option we considered of installing fin type active stabilizers. These work extremely well to reduce the roll in many conditions when on passages but they would also introduce a Domino Effect of consequences that took them out of the running for us, such as;
- their protrusion from the side of the hull reduces the safety factor when in areas with uncharted rocks, coral heads and the inevitable groundings on these.
- not suitable when ice is present in polar waters
- unlikely but possible if a fin is hit hard enough to create an underwater breach of the hull
- are extremely complex and often top the lists of most maintenance problems we read from other global passage makers.
- most require a significant hydraulic system to operate which adds yet another whole system onboard to maintain and repair.
I might add that having gone through this Domino Effect as we considered active fin stabilization, it also helped us see that we could find a different type of active stabilization if we should ever want that, and one that eliminates most of the dominos I listed above. This would be stabilizers that use the Magnus Effect which is offered by several different manufacturers now.
Does it pass the Goldilocks test?
We essentially answer this question by virtue of having gone through all the questions and priorities I’ve already listed. Because we have highly personalized our overarching principles of SCEM and articulated much more detailed specifics of our use case, our decision making helps us ensure that we are making choices and decisions that are by definition, Goldilocks, just right, just for us.
However, this is such an important factor for us that we do keep coming back to to this “Goldilocks Test” to make sure we are avoiding the tendency to “go with the flow” of following what others are doing or “the way its always been done” and are staying true to ourselves and our preferences. I will site a more “meta” example here which is our decision in the design phase to “upsize” the length of the boat from the 18-20m / 60-65 ft that we initially imagined and then at the same time “downsize” the interior to have just 2 cabins and 2 heads.
Our decision to extend the length to 24m/78ft was driven two factors; simple physics that hull speed is a factor of Length on the Waterline and our discovery that contrary to popular opinion there is not very many restrictions on boats that are over 20 meters whereas there are some very significant changes to the rules governing ships that are over 24 meters. With our prioritization of efficiency, we pushed the length to just under 24 meters. With our infrequent use of marinas the increased docking fees do not affect us very much. Furthermore, with more and more catamarans being purchased, many marinas are changing their dock rates to be calculated based on overall area of each boat, LOA x Beam and so our slender 5m Beam reduces our overall area and we are often cheaper or about the same as much shorter but wider boats.
Our decisions to “downsize” the interior and thus reduce maintenance and costs was based on the fact that 99% of the time Christine and I are the only two people living onboard so we wanted to make the interior fit us and our needs. Our Master Cabin is very spacious and luxurious for us. Our Guest Cabin works very well when we do have guests onboard but most of the time it is a very purposefully designed Office for Christine Kling, the Captain’s nom de plume when she is working on her next book and running her growing book business. Our SuperSalon is indeed living up to that name the more we live in it. And my very full size Workshop and Engine Room is that of my dreams.
There are many other examples of how the Goldilocks Test has driven our decisions such as;
- Manual Paravane system and Tender Davit that is KISS and as former sailors handling lines, winches and clutches is second hand.
- Though we designed and built the cabinets, electrical and plumbing for them, we chose not to install either a Dryer or a Dishwasher as we are just not fans of either one and prefer washing and drying by hand.
I could give countless more examples of how we have applied the Goldilocks Test to almost every decision we have made during the design and the building process but I think you get the idea. We have now been living aboard Möbius since she first launched in February and we are finding that our continuous use of this Goldilocks Test has worked eXtremely well for us in designing and building Möbius and we can and do recommend it highly for almost all decisions and choices you make.
New vs Tried & True?
Christine and I are self described nerds and geeks so we have a great fondness for technology that is on that well named “bleeding edge” and we have a full compliment of devices to show for it. However, when it comes to equipment for Möbius, and especially all of it that is on that Must Have list, it must be remembered all those decisions must be made within the context that Möbius is an XPM type boat that is designed and built to live up to that acronym for eXtreme eXploration Passage Maker. So when it comes to deciding on equipment, materials, construction and design of these items, they must, all be Tried & True. To us this means equipment that has been in regular use on boats, ideally with similar use cases as ours, for several years and has stood that test of time.
Some examples of this for us include:
- we delayed our decision to go with FireFly Carbon Foam batteries until after we had been able to find enough examples of these batteries being installed in other people’s boats in large numbers for many years.
- We chose to go with all Furuno for navigation because it is so widely used by commercial boats in fishing fleets, government agencies and the like and hence this equipment is designed and built for continuous 24/7 use in some eXtremely harsh conditions. They also have an excellent reputation for their continued support of even their oldest equipment.
- Our decision to go with a Gardner 6LXB engine that is still one of the most efficient diesel engines ever produced and is still in use in thousands of commercial boats worldwide. It is also perhaps one of the best examples of the KISS approach to design and engineering which adds to how well it passes the Tried & True test.
- individual MPPT controllers for each of our 14 solar panels as this has been well proven to be the most efficient combination for both overall efficiency, least affected by shading and highest redundancy.
Let me end with a final example of the value of taking this Tried & True test for mission critical ships and equipment from no less than the US Navy!
A recent article caught my eye a few weeks ago where even the us Navy has learned the folly of installing untested equipment on their ships. This link to the article USS Gerald R. Ford Problems: The Navy Admits Its Big Mistake (popularmechanics.com) provides a brief but telling story.
as outlined in that article the Chief of Naval Operations, Mike Gilday, says the U.S. Navy built the aircraft carrier USS Ford with too many new technologies. such that now, the Ford is several years behind in its life cycle because of problems with many of those new technologies.
- The last of the Ford’s four advanced weapon elevators, the most glaring example of the ship’s tech gone wrong, should enter service later this year.
- When the Navy first built the Ford, it incorporated nearly two dozen new technologies, some of which are still giving the service headaches 4 years after the ship entered the fleet. Those delays meant the Navy only commissioned the Ford in 2017, despite laying it down in 2009. Even then, problems lingered, especially with the electromagnetic aircraft launch system (EMALS) and the advanced weapon elevators (AWEs).
- The ship’s first full deployment, originally scheduled for 2018, is now set for 2022.
I think this unfortunate real world example does help to make the point that for XPM types of boats with use cases to match, all the “mission critical” equipment onboard MUST have passed the Tried & True test.
Bubble Bubble, Toil & Trouble!
Leaving you with the latest bit of kit that Captain Christine just approved and installed onboard, a fully manual sparkling water maker! Especially in these hot summer months, Christine particularly enjoys her cold sparkling water and I do too but we don’t like having to buy it in cases of plastic bottles. We have our watermaker for similar reasons for our regular drinking water. Initial tests have elicited the same smile you see here so this item has now passed the all important Captain’s Test and has been welcomed aboard.
Thanks so much for making it this far if you have and I do hope that this slightly different format and content is of interest and value to most of you. Let me know either way with your comments in the “Join the Discussion” box below and I’ll be back with more for you same time next week.
I’m sure it will be a good but, but 5 years in the making is too long for most people.
It is indeed a very long and winding road to design and build a very custom new boat from scratch and not an experience that most would be up for I’m sure. Boat building is new to me but Christine has been through several in her life long experiences with boats so we have been pretty good at setting our expectations very conservatively, expecting this whole experience to be in the 4-5 year timeframe. So that is pretty much playing out now as we work our way through this final stage of commissioning, testing, etc. All in all it has been an adventure of a lifetime with all the ups and downs that would imply but one that we are very pleased to have gone through. As with all the other “storms” we have gone through when out sailing, these experiences with all their new levels of “how low is low?” are the same ones which enable us to experience equally new highs of joy after having lived through them and make all those sunsets from our deck that much more profound.
Fair enough, your time, your money, your decision. But most of us who wanted a boat , one probably just as good, would just have bought something like a used Dashew boat, got the keys, sailed away.
Yes, we considered that option and have been on many FPB’s over the years. And you are quite right I’m sure that buying a used boat would have been what many chose to do and if that worked well for them then more power to them. For us we were simply not able to find an existing boat at any kind of reasonable price that met our needs and ticked off most of our requirements so the choice of designing and building our own became more and more appealing and ultimately the choice we made. As I hope most others can do, in the end we made the choice that worked best for us and we are still singing “Did it my way” with smiles on our faces which we expect to get even larger in the ensuing years of cruising the world on our Goldilocks just right, just for us boat. Hope you find or already have yours too.
Wayne – another telling and fact filled article. One point I’d add to the list in selecting suppliers for is consolidation, meaning placing more orders with a smaller number of suppliers. By that means they are encouraged to provide the necessary up front design and post launch commissioning. It can come at a cost but a cost lessoned by reducing the number of system interfaces.
I noticed also the reference to Portland Pudgy. We were looking at those also as a fun and indestructible jolly boat plus secondary life raft. Might just go buy one!
Thanks Chris, appreciate the feedback.
Your suggestion about consolidating has some merit and we did a fair amount of that by using the same gear and/or same manufacturer for much of our equipment. Pumps come to mind where we were able to go with the same company and the same models in many cases for most of the many, many, many, pumps we have onboard Möbius. The driving benefit for me is in the realm of our priority on maintenance, lack thereof, when I don’t need to stock so many spares for these pumps as they all use the same impellers, fittings, etc. And if they require any special tools then I can have those and less of them. I can also be much more familiar with each bit of kit we have when there are fewer new and different makes and models of things.
When it comes to your expectations that consolidation will result in better up front design and post launch commissioning, I am less convinced. For example, most of the systems on an XPM are not able to use a single supplier for the every part of the system and so expecting to get this up front design from a given manufacturer is often not possible. If you are going to outsource this systems design work then in my opinion a better option is to work with a well experienced professional systems designer or expert in the trades involved. I’m thinking here of systems such as electrical (AC/DC), navigation, plumbing, monitoring, etc. This allows these experts to work with you the owner to choose the equipment that best fits your needs and your boat and make these choices from multiple brands if that is the best choice.
Things have really improved a LOT in the past 10 years in particular when it comes to standards which make it much easier to combine multiple brands in one system using these more standardized “system interfaces”. NMEA2000/N2K would be an example for things like navigation electronics and then in the fundamental trades such as plumbing and electrics, going with similar standards from the very beginning such as all the same types of plumbing fittings, NPT vs BT threads for example. In electrical systems we did go with mostly all Victron for our AC/DC equipment but chose to go with FireFly Carbon Foam rather than Victron OPzV as the Carbon Foam batteries were the Goldilocks choice for our 24V battery systems.
All my long winded way of saying that for me, the key is in the design of the systems, down to a very detailed level and given that few if any systems can come from any single manufacturer, the key is to find and hire a person who has the experience with both the equipment and their use in eXpolorer style boats and use cases as close to yours as possible.
Commissioning has similar limitations in my experience for the same reasons that few if any systems involve equipment from just one manufacturer. Furthermore, commissioning by manufacturers does not cover the actual installation so they are not able to ensure that any given system will be up and fully operational as their scope only includes the equipment itself and not the installation. In the case of systems such as electrical and navigation for example, the manufacturer’s reps can test out and configure the equipment itself but they can’t do anything other than report to you any parts their equipment requires that has not been installed or anything that has been installed incorrectly. So you end up “stuck in the middle” with such situations. Better choice in my opinion is to hire an experienced person who may or may not be the same one as you might have hired for the design phase I described above, and hire them relatively early in the whole build process, to do a very detailed audit of each system onboard. It would likely be possible to find just two or three people to cover all the trades and systems involved and these people can and provide their report to the owners and builder for them to be aware of and fix accordingly. To my way of thinking this would result in the least amount of disagreements between builders and owners and the most complete and fully functioning boat in the end.
Of course all this just my two Canadian cents worth on all this and what matters the most is that you make all these decisions based on what is best for YOU and YOUR boat. Best wishes to you and Sebrina as you now work your way through this labyrinth of decisions in your building of XPM78-02 Vanguard and we look forward to learning more as we follow your progress.
This article is worth its weight in life, which is more precious than gold by a long shot. Four principles and five questions. Adaptable to a world of applications
High praise coming from you John so thanks much for that!
You are quite right in noting that this kind of approach can be adopted to a limitless number of diverse applications in life and I have definately tried to gather up all the lessons in life I’ve learned so far and synthesize these down to such core principles and subsets of criteria. Has worked well for me in life in general so I just did the same for designing and building this new boat. A multitude of new lessons learned in the process of course, but this framework of decision making served us well and I will now continue to refine and use as we transition from building to using.
Thanks for all your thoughtful input and look forward to more as we continue this voyage.
“What problem is Lithium trying to solve?”
four reasons for choosing lifepo:
– Energy density. More is more, and if weight is needed, more capacity is a bonus
– Cycle life
– Charge acceptance
– Peukert efficiency
Hi Andy. I think I listed these same attributes of LiFEPO4 batteries but in the absence of all the context for the boat and the use case that these batteries will be used for, they are not of much use. In this post I tried to add all the context surrounding how we will use our battery banks and the conditions the boat will be in and how these made the decision to go with Carbon Foam a relatively clear and easy decision. For our use case, these CF batteries met our conditions the best and while still early, only 6 months of use so far, their real world data results are exceeding our expectations and we are delighted with our decision.
As I tried to conclude that post, I hope people will not misconstrue our decisions and choice of battery type in this case to be “the best” for any other boat and owners than us. My hope was that by explaining the logic and decision making process we used, this might be helpful for others to use to make the Goldilocks choice of batteries for them and their boat.
Regarding the stablizers, a conventional fin stabliser can nowadays be electrically or hydraulically actuated. I must confess I fail to see how such a fin is substantially more “extremely complex” than a stabilizer of a magnus type.
There is roughly the same amount of moving parts in both, if not even more with magnus, when you count the motor for moving the magnus pipe between working and stowed position. In fact, a fin stabilizer does not differ in complexity that much if you compare it to a rudder and steering system.
And there are multiple stories of those being damaged, with no major damage to a vessel hull, especially with aluminium boats.
Horses for courses as the saying goes right Andy. My experiences and discussions with others regarding the different choices for active stabilization does not match up with yours and my conclusion is as I wrote that while ANY active stabilization system is relatively “complex” the Magnus Effect style are a bit less so and more robust in operation.
I can only go by the steering and rudder systems I’ve had on my boats or ones I have worked on but based on that steering systems are at the other end of the complexity spectrum from active stabilizers of any type. I went with Kobelt for our steering system after having such great experience with them in my previous boat and that critical system is rock solid and working even better than expected in our early testing so far. As for stabilization, we have chosen to go with passive paravanes and we’ll run that for the first year or two to test them out in all conditions and see how well they meet our needs. We designed and built the hull to already have all the framing for active stabilizers of any type should we decide to go that route in the future. And of course by then I’m sure there will be lots of new choices and more real world use of all of them to help us with that decision should be want to go that route.
Thanks as always for your detailed responses and alternatives.
I’ve been reading your blog for around the last year, I like the analytical approach to the design and equipment selection, it exactly what I would do were I in the same situation. I find it interesting that so many boats are built without this approach leaving me cringing at some of the equipment and system you see installed.
All the best and look forwards to following your journey.
Hi there Sean, welcome aboard so to speak and thanks so much for commenting.
It is eXtremely helpful to get this kind of detailed feedback on my posts to know how well they are or are not proving to be of value to my readers. These online forums are great but compared to a “live classroom” in my former years being a teacher and keynoter, their “feedback free” nature makes it quite challenging to know if what I’m sending out is being well received when I can’t watch their faces and body language.
So thanks much for taking the time to send this comment and please do more as something you read prompts you to; good, bad or otherwise.
Thank you Wayne for the excelent discription of the way leeding to the housebattery choice.
It makes total sense in your case to go with lead….
Andy made some good points, for the Lithium corner, but he left out the price to pay for “more is a bonus”.
Have you looked into (internal) gyro stabilizers? No drag, no external things, installed at the centerline……..
Gutten Tag TC! Thanks very much for your kind feedback.
I did not address it too specifically in my last article and I was going to add a section on “Value” as one of the criteria but ran out of time. No question though that based on my calculations, Carbon Foam had a much better valuation, “bang for the buck” for Möbius than Lithium. GEL, AGM and FLA could have also had very good valuations and I’ve had all of them in former boats but it is the sum of the answers to all the questions I outlined that matters most in the end to make the final decision as to what battery type or any other equipment, is the Goldilocks choice for us. As I tried to outline in that post, CF batteries came out on top by a considerable margin when we evaluated them against all four of our SCEM priorities and the specifics of our use case for Möbius. Price was amongst those criteria and the CF batteries scored highly in that regard for us, but only as one of the many other factors such as lack of maintenance, high cycle life/battery lifespan, use in low temperatures. Perhaps most of all for me, their eXtremely high ability to continue to perform well in conditions that would be very threatening to other battery types such as being in partial SoC for long periods of time and not suffering any sulfation. Using solar as our primary charging source negates any benefit from the high charge acceptance rate for lithium and so as I wrote, in the end the choice of Carbon Foam batteries for Möbius was a relatively clear and easy one to make.
Regarding gyro stabilizers, we have indeed looked into them for the past few years and I think they are becoming a better and more proven choice for more and more boat owners and manufacturers. They do have some very compelling advantages, most of which you noted. In our use case the lack of any external protrusions from the hull so no concern about hitting submerged items and zero drag would factor highly positively in our decision making.
Keeping in mind that it was several years ago when we were making our decision on stabilization, gyro companies and models were still relatively new and so they did not have the critical “Tried & True” factor I require. This is changing over time as more and more gyros are being installed but if I were making the decision today I would still not go with gyros because they have not yet had enough real world installations and hours as I would want.
Another factor for gyros is their relatively high energy consumption and while we would only chose to use active stabilization when underway and therefore our twin 250A @ 24V alternators would always be available and could easily meet this added energy requirement, it would still be a significant reduction in our overall power and fuel efficiency so that factors into my thinking as well. And while they are also getting better in this regard, from the research I’ve done, when mounted in a very rigid metal hull such as ours, it is challenging to mute the vibration and noise of a gyro. I have no doubt that manufacturers will and are reducing this with better insulation, bearings, etc. and much of this can be mitigated with good vibration dampening installations, but noise, lack thereof, is a very big factor for us so this would be part of our decision making for a gyro.
Hope that helps put our decisions in better perspective for you and help show how our primary goal is to make the decisions that are the Goldilocks ones for us and not to be misconstrued as best for other boats and owners.
Thanks again for joining and commenting. Hope you willl continue to do both.