XPM78 - Explorer Yacht

[Chris Leigh-Jones]

I am new to this forum but have been reading a long thread, now closed, about an FPB64. It seemed to have become a bit heated which is a pity as its a subject I am interested in.

My wife and I are building a similar vessel at Naval Yard in Antalya. I was inspired by a blog written by Wayne and Christine re their own XPM 78 - Mobius. I was 10 years deep sea and 45 years in the shipping industry, all of it commercial shipping bar a few months. We are all influenced by our backgrounds, me as much as anyone.

Searched for a boat for a couple of years that was suitable to take our family on adventures but never really found what we were looking for though Nordhavn, Fleming and Bering came close. I spoke at length to Sue at Berthon and came close also with an FPB then decided to build our own. 78 foot, low fuel consumption, stable, quick, short handed. It's going to cost us but is also my last hurrah so I don't really mind. I found the Mobius blog inspiring from a similarly inclined sailor. They are not for everyone but what is in this world?

My long suffering wife is an interior designer, FPB was an aesthetic step too far for her so now we get to compromise. The yard have worked with us to respecify along my commercial lines of thought and engineering bent. I'll post progress up as it happens. Hull plates are cut and on their way from Istanbul. Hello everyone. Chris

 

[PM]

Wow, Welcome aboard. Sounds like a huge project, try to stay sane..

pete

 

[MRRiley]

Heck of an intro. Post pics when you get a chance. Looking forward to following along and hearing about your equipment choices and yard experiences. Welcome aboard!

 

[Chris Leigh-Jones]

Thank you for the welcome. I have been working with the yard on the General Arrangement so thought it may be worth posting up. Drawings have Dennis at Artnautica to thank. I like this work, cost conscious, economic and stable.

 

[Chris Leigh-Jones]

View attachment Vanguard.pdf

 

[Chris Leigh-Jones]

Aluminium for decks and jigs just arrived. Laser cut in Istanbul then trucked to Antalya. They are removing oxide pre-welding. No going back now.

 

[Chris Leigh-Jones]

Aluminium for decks and hull jigs arrived. (I'm working on uploading skills!)

 

[socalrider]

Wow! Subscribed - thanks for posting & looking forward to seeing your journey. What are your cruising plans?

 

[Chris Leigh-Jones]

Want to take my family to some out of the way places. Went to Murmansk once, over the North Cape so that's on the list maybe Svalbard before the ice melts. Carib for giggles, Nova Scotia though is probably more interesting. Med and West Coast of Europe, Wales and Scottish Isles, I heard Ireland was a good gig also. Not sure I'd go back to West Africa, bad memories. Japan is worth a long visit its so same-but-different. Aleutian Isles also. Got to do Straits of Megallan on the way back. Rio Platta in to the Pirana to re-live an old trip. Might visit the Falklands, maybe Porto Alegre, 300 miles up a lagoon or the Amazon, got to Manaus once, took for ever. Preferably anywhere you don't readily find tourists and they can't speak English.

 

[IRENE]

Hello Chris and welcome. This will be a great thread, thank you for sharing your adventures.

I really like the concept of the boats such as FBP and Artnautica and yours. How will she be powered?

 

[Chris Leigh-Jones]

Jeff- thanks for the kind welcome. We need about 150bhp for 11 knots. She has a hull like a yacht with the keel cut off so is pretty slippery, hull speed is 12 or 12.5 (?). We will fit 2 times JDeere 4045 AFM 85 giving 100% redundancy, Tier 3 compliance in case we want to US Flag. I was an engineer so we decided to play with hybrids also. Need 2 by 30bhp high voltage DC for maneuvering but the twist is battery charging at a reasonable timeline so we will fit 2 by 70bhp at about 1200 shaft rpm (from memory) giving also 2 by 130 at 2300 rpm for charging when de-clutched from the shaft lines. Motors have a step down drive before the gearbox at 1.7:1. Specked a big LiFePO battery bank also. Battery tech is changing quickly with Electronic Vehicle development so I'd expect to change that out at some future date as new tech comes on stream with better power density. Power gear supplier is Praxis Automation, step down is Esco Power.

 

[Chris Leigh-Jones]

Sorry Irene, I wrote your name was Jeff for some random reason. That 2.52 am for you!

 

[twistedtree]

What are your goals with the hybrid system, and what benefit do you see?

 

[Chris Leigh-Jones]

What are your goals with the hybrid system, and what benefit do you see?

Twistedtree. Sir, the most honest reply would be that as an engineer I'm fascinated by new(ish) technologies so get the opportunity to play with that concept. It does allow us to dispose of generators (1 or 2 off). It gives extended very quiet if somewhat slow circa 4/5 knot operation. (We have an efficient hull which helps the batteries in this respect.) And its allowed us to implement as very responsive Dynamic Positioning system so I maintain peace and harmony with my wife and achieve virtual anchoring for short daylight periods at least until we build some trust. It will do this without a stern thruster or pods (hopefully).

 

[Chris Leigh-Jones]

Jigs are being installed to set the bulkheads and frames.

 

[Chris Leigh-Jones]

Still trying to get used to uploads.

 

[Chris Leigh-Jones]

Ahhh!

 

[sunchaser]

Chris
If you've not done it already check out Dashew's website from 15 years or so ago covering the Windhorse concepts and build process. It also had twin JD 4045s. Will your vessel have twin keels, huge fuel capacity and thick glass similar to the FPBs?

What do you foresee for build time? Sounds fun and challenging.

 

[Chris Leigh-Jones]

Chris
If you've not done it already check out Dashew's website from 15 years or so ago covering the Windhorse concepts and build process. It also had twin JD 4045s. Will your vessel have twin keels, huge fuel capacity and thick glass similar to the FPBs?

What do you foresee for build time? Sounds fun and challenging.

Thanks Sunchaser. Their FPB web site www.Setsail.com and free on line books have been inspiration for me in finally deciding which way to go. Time has it though that no more are being made but it seems to have set off a following with new designs along allied lines form Circa Marine, Arksen (love the marketing) and Artnautica. We chose the Artnautica design and Naval Yachts as our yard. Equipment wise we can specify whatever we believe works with our expectations. They have been very flexible only pushing back when the challenge is pertinent (I can blindside myself on occasions). This Trawler Forum always has been one of my favorites. So much salted experience freely given, pay it forward seems to be the ethos and its very helpful to the less than initialed in finding their way.

Yes twin keels, 7000 miles in the tanks at 10 knots with 20% reserve last time we calculated though I've added a bit of weight so lets say 6000. We will use the water maker to ballast compensate as the fuel is used up. Glass is toughened and laminated, pretty thick, ¾" from memory and bonded in to the frames, none opening except for deck hatches that use the same glass. I build homes local to Charleston SC in a Wind Zone, I'd equate it to Hurricane rated and then a good extra margin from the structural thickness. It may crack but should not burst. We also down angled the helm screen to limit glare and help the HVAC a bit. Build time is 18-22 months, not sure about that though.

Regards from a Cat in the USBVI, no wind so motoring everywhere this week.

 

[guy with a boat]

Sounds like a dream project for an engineer or any boat geek. I like your management style: cruise the BVI on a cat while the work is underway.

I look forward to following the adventure.

 

[Chris Leigh-Jones]

Thanks for the kind words, Guy with a Nordhavn. Photo is lunch and child No 5 still at home. There was a nice Nordhavn moored this morning in St Thomas, wasn't you was it?

 

[Chris Leigh-Jones]

Looks like we have finally settled on the DC power system. Reduced the size of the traction motors from 50 to 30kW at circa 350rpm shaft to give the batteries an easier time on discharge. Twinned the DC/AC frequency converter and 230VAC three phase transformers for redundancy. We added a small 24VDC Firefly house battery bank for cold start and to power the diesels if we loose the main battery bank. Also runs all instrumentation and powers DC/DC converters for 48VDC. Might twin that bank at some future date but it depends how the technology develops. 230VAC transformers will also provide isolation from rogue shore supplies. High voltage DC will be distributed via bus bars running inboard. Solar (8kW) will charge house batteries and when full charge back via the inverters to supplement power bank. Main house load can be drawn from house bank or high voltage DC power bank. We'll add an energy management system to track this lot. Should be able to anchor for years, does that me a "prepper"?. Hope it works.

 

[Whodgins]

I am new to this forum but have been reading a long thread, now closed, about an FPB64. It seemed to have become a bit heated which is a pity as its a subject I am interested in.

My wife and I are building a similar vessel at Naval Yard in Antalya. I was inspired by a blog written by Wayne and Christine re their own XPM 78 - Mobius. I was 10 years deep sea and 45 years in the shipping industry, all of it commercial shipping bar a few months. We are all influenced by our backgrounds, me as much as anyone.

Searched for a boat for a couple of years that was suitable to take our family on adventures but never really found what we were looking for though Nordhavn, Fleming and Bering came close. I spoke at length to Sue at Berthon and came close also with an FPB then decided to build our own. 78 foot, low fuel consumption, stable, quick, short handed. It's going to cost us but is also my last hurrah so I don't really mind. I found the Mobius blog inspiring from a similarly inclined sailor. They are not for everyone but what is in this world?

My long suffering wife is an interior designer, FPB was an aesthetic step too far for her so now we get to compromise. The yard have worked with us to respecify along my commercial lines of thought and engineering bent. I'll post progress up as it happens. Hull plates are cut and on their way from Istanbul. Hello everyone. Chris

Gunaydin (aka Good Morning) Chris & Sebrina, and an eXtremely BIG Welcome to the family mv Vanguard from your XPM78 sister ship mv Möbius now afloat in the Harbour inside the Antalya Free Zone. We could not be more excited for you and for this significant growth of the XPM family.

Sorry to take so long to respond here but the past month has been particularly hectic after our long awaited launch and now all the work to commission all our systems and play a giant game of Whack-a-Mole chasing down all the gremlins.

I don't get back to the Naval Yachts shipyard as often since we launched but every time I'm there I take more photos since the beginning of the construction of the steel frames on the floor and now the preparation of the thousands of CNC cut aluminium jig saw puzzle pieces that will soon be Vanguard's hull. I will upload those to you along with more details over the weekend but wanted to at least send off this hearty congratulations on the start of your new build and welcome you and Vanguard to the XPM family.

-Wayne & Christine
Proud Owners of XPM78-01 Möbius

PS:
For those interested in more details and photos than you would ever want to know about XPM78-01 Möbius, my wife and I have been posting weekly progress updates for almost four years now of the design and building of mv Möbius at https://mobius.world

Please feel free to contact me with any questions you may have about the XPM series at wayne.christine@mobius.world

 

[twistedtree]

I'm real interested to follow how the whole power system works out. I went through a bunch of gyrations when planning out boat, mostly hoping to reduce the number of diesel engines. I wanted a single main propulsion engine, so the focus was on backup propulsion, generators, and aux hydraulic power.


I mostly focused on ways to combine the wing engine and the bigger (25kw) of the two generators. But eventually ended up back with each as a separate machine, and it really came down to the wide spread in power requirements.


Aux propulsion is the biggest consumer at the wing's rated power of 160hp. That moves the boat 5.5 to 6 kts which is quite acceptable. Now that's via an off-center, folding prop, so if backup propulsion was via the main shaft and prop it would take less HP, but also reduce redundancy by giving up the second shaft and prop.


Hydraulics are quite a bit of power too; around 100 hp in the worst case.


Power generation is pretty modest. The 25kw generator is perhaps a 40 hp motor. I'm not sure exactly, but it should be right around there.


I considered using big generator for everything, and use electric drive for hydraulics and backup propulsion. But it would need to be around 100kw to serve the backup propulsion need, so a massive generator. Plus, when used to generator electricity for house use it would be significantly under loaded.


So, I ended up back with a wing engine with direct drive to a folding prop, and a PTO driven hydraulic pump for hydraulic power. Plus a more modest generator for generating house power. Each is well proven at the task, which helps with overall reliability.


But that's just where I ended up. The best part about boats is there are lots of right answers.

 

[Mako]

I wanted a single main propulsion engine, so the focus was on backup propulsion, generators, and aux hydraulic power.

So, I ended up back with a wing engine with direct drive to a folding prop, and a PTO driven hydraulic pump for hydraulic power.

What's the backup for hydraulic power should the wing engine be down? Do you have a PTO from the main, or perhaps an electric-driven hydraulic pump?

 

[twistedtree]

What's the backup for hydraulic power should the wing engine be down? Do you have a PTO from the main, or perhaps an electric-driven hydraulic pump?

Yes, both, actually. But mostly the main engine. It can run everything, just not all at once at full power. And it runs the stabilizers while underway. Then there is an electric pump for stabilization at rest. Northern Lights preferred that to a PTO on the generator, plus it lets me run off either generator. Apparently the PTO clutches like to be cycled periodically rather than left on continuously as with stabilization at rest.

 

[Chris Leigh-Jones]

I'm real interested to follow how the whole power system works out. I went through a bunch of gyrations when planning out boat, mostly hoping to reduce the number of diesel engines. I wanted a single main propulsion engine, so the focus was on backup propulsion, generators, and aux hydraulic power.


I mostly focused on ways to combine the wing engine and the bigger (25kw) of the two generators. But eventually ended up back with each as a separate machine, and it really came down to the wide spread in power requirements.


Aux propulsion is the biggest consumer at the wing's rated power of 160hp. That moves the boat 5.5 to 6 kts which is quite acceptable. Now that's via an off-center, folding prop, so if backup propulsion was via the main shaft and prop it would take less HP, but also reduce redundancy by giving up the second shaft and prop.


Hydraulics are quite a bit of power too; around 100 hp in the worst case.


Power generation is pretty modest. The 25kw generator is perhaps a 40 hp motor. I'm not sure exactly, but it should be right around there.


I considered using big generator for everything, and use electric drive for hydraulics and backup propulsion. But it would need to be around 100kw to serve the backup propulsion need, so a massive generator. Plus, when used to generator electricity for house use it would be significantly under loaded.


So, I ended up back with a wing engine with direct drive to a folding prop, and a PTO driven hydraulic pump for hydraulic power. Plus a more modest generator for generating house power. Each is well proven at the task, which helps with overall reliability.


But that's just where I ended up. The best part about boats is there are lots of right answers.

Looks like you had your own can of worms to sort out. I heartily agree with your ending statement regarding lots of right answers. Mismatching of power needs and a propeller power curve work to make the equation a difficult on to solve elegantly. In our case the batteries act as the central Node, powering most things and accepting power from disparate sources. Battery technology is still not where it needs to be but Electric Vehicle adoption seems to be spurring some marvelous developments now out of the labs and in pre-production. LiS batteries for example, just wish the cost would come down faster.

I think we have managed to dispense with generators and limited our hydraulics to just the steering gear, time will tell. The hybrid though was not a cheap solution. I am now planning the day when I can ask my son to "engage the hybrids, take her out", I always was a bit of a Start Trek fan.

 

[Chris Leigh-Jones]

Had an update for the yard today. Main deck is welded and set on the jigs ready to stand the bulkheads. They sanded the surface where welds will fall so we have clean metal to weld to.

 

[Dav]

Aux propulsion is the biggest consumer at the wing's rated power of 160hp. That moves the boat 5.5 to 6 kts which is quite acceptable. Now that's via an off-center, folding prop, so if backup propulsion was via the main shaft and prop it would take less HP, but also reduce redundancy by giving up the second shaft and prop.

I considered using big generator for everything, and use electric drive for hydraulics and backup propulsion. But it would need to be around 100kw to serve the backup propulsion need, so a massive generator. Plus, when used to generator electricity for house use it would be significantly under loaded.

How about that 80kW DC diesel generator instead of that wing engine? 80 kW is just a rough estimate, but it should equal conventional 160 hp wing engine pretty much.

Have backup propulsion as a 80kW electric motor driving the same second shaft with folding prop, or even more ideally 2 smaller similar 40kW props / underbody pods so that the thrust is symmetrical? This backup propulsion is always available within seconds, if two shafts / pods maneuverability comes as a free bonus.

Could also have a backup / aux motor on main shaft for entering / exiting marinas in priceless silence.

Then for the generator loading, have a sufficient battery bank to absorb full output of generator at 1C max, ideally 0.5C. Then generator only runs for a short time, and all the hotel loads are supplied by an inverter.

 

[Chris Leigh-Jones]

How about that 80kW DC diesel generator instead of that wing engine? 80 kW is just a rough estimate, but it should equal conventional 160 hp wing engine pretty much.

Have backup propulsion as a 80kW electric motor driving the same second shaft with folding prop, or even more ideally 2 smaller similar 40kW props / underbody pods so that the thrust is symmetrical? This backup propulsion is always available within seconds, if two shafts / pods maneuverability comes as a free bonus.

Then for the generator loading, have a sufficient battery bank to absorb full output of generator at 1C max, ideally 0.5C. Then generator only runs for a short time, and all the hotel loads are supplied by an inverter.

Dav - I like the thinking. Vanguard is designed along similar lines. We can charge 60kWh batteries in an hour if we have to or better 2 hours without stressing them. Thats keeps the diesels loaded a little as well as supplying hotel loads. Thereafter the hotel load is fed from the batteries via inverters with nothing else running. My ever helpful wife has promised to do all the high power things like washing whilst charging (should probably do the washing myself in this era.). I'll agree a slot in the day for her. Thanks for contributing.