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Old 10-08-2016, 19:10   #46
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re: Why little popularity in pocket cruising catamarans?

Interesting, see I would call "pocket" under 30'


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Old 10-08-2016, 21:19   #47
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re: Why little popularity in pocket cruising catamarans?

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Interesting, see I would call "pocket" under 30'


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Yes, its interesting that it wasn't so long ago that a 30 odd footer was a good size cruiser.An Oceanic 30 or Heavenly twins for instance. A witness 35 or simpson 10.2 was considered palatial even though neither had full standing headroom throughout.
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Old 10-08-2016, 21:34   #48
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re: Why little popularity in pocket cruising catamarans?

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Yes, its interesting that it wasn't so long ago that a 30 odd footer was a good size cruiser.An Oceanic 30 or Heavenly twins for instance. A witness 35 or simpson 10.2 was considered palatial even though neither had full standing headroom throughout.
Well when the financial crisis hit - most non-essential goods had to go upmarket as only the top had the liquidity to keep spending. Most people with means don't go spartan to avoid marina fees.
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Old 18-08-2016, 19:46   #49
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Re: Why little popularity in pocket cruising catamarans?

Some of my initial research led me to believe you that you purchase the smallest boat possible for your needs. Small pocket cruising catamarans under 30' should be made from aluminum and powered by solar energy, lithium batteries and electric motors.

The absence of that production line is why there is no popularity. The climate is right for the introduction of solar electric catamarans. The technology is ready. Where are the companies that could easily be cashing in on the free publicity from all the climate change news stories.

As Bobcat can attest to "Katiki" was notably one of the earliest pocket cruising catamarans available for public purchase. They can still be found but then most people will have issues maintaining a boat made in 1964.

From a weight perspective my fully loaded weight on my solar electric catamaran came in at 5400 lbs. It is easily propelled by electric motors and has unlimited range. Cost $600 a month to own including marina fees, insurance and comes with all the conveniences like washer, electric head, hot water heaters, atmospheric water maker, induction cook tops and as a bonus very comfortable, very dry catamaran.

The question remains can these very stable designs be made from aluminum and at what cost from a weight perspective and a financial perspective. Leave the electrical outfitting to the buyer. From the inside looking at the stringers it wouldn't appear to be that difficult to recreate from aluminum.

For now though I'm quite happy with my Bobcat Catamaran. Doesn't take much to see a video with a simple search for solar electric catamaran. After all sailing or boating isn't about how fast you can go but how far and how steady - especially in terms of electrically propelled boats.

Provide a light aluminum hull and let the people open source the outfitting to their desire.
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Old 18-08-2016, 19:56   #50
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re: Why little popularity in pocket cruising catamarans?

Aluminium doesn't save weight over composites until very large sizes and uses horrifying amounts of energy to smelter. If you want to go green, plantation timbers like Paulownia and soy based epoxy is the way to go. Sails and wind is cheaper than solar, especially trans ocean. IMHO.


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Old 18-08-2016, 20:22   #51
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re: Why little popularity in pocket cruising catamarans?

I certainly am not advocating this from a green perspective per say. Yes there are elements that some might preclude to being part of some green movement or desire to market that way.

I'm not really concerned with how much energy it takes to provide raw materials for the smelting of aluminum. I am interested to know if the basic design of a Catalac, Bobcat, or Gemini could be mass produced quickly from aluminum minus all the obsolete sailing stuff in just a plain jane powered catamaran fashion?

Kind of a loaded question there isn't it. IMHO densities of energy storage and solar return make sail and wind driven boats non essential for trans ocean IMHO. There just don't seem to be a huge ground swell of people doing it.

Personally the overly complex maintenance schedule, high cost of outfitting and rigging to sail is what ultimately turn me off from going sail and wind. Know anyone that needs a brand new 42' aluminum extrusion? If anything all that should be required to propel with wind would be an easily maintainable affordable solid wing mast but then that is a project for another day.

I would assume strength wise composites are probably stronger or at least as strong as aluminum would be. If the weight could be drilled down on a basic model and mass produced then everyone would want one. That is the basic formula - mass produce quickly for affordable price and provide stable platform.

Otherwise try finding pocket cruising catamaran for sale and end up with old school crap hanging off your boat that has to be removed before a proper conversion can take place.
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Old 19-08-2016, 12:18   #52
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re: Why little popularity in pocket cruising catamarans?

Sorry but all else being equal a small aluminum cat will weigh more than a fiberglass version.


Producing a Gemini, Catalac or similar hull from aluminum doesn't work because they were designed for fiberglass construction. Maybe a wharram as many of those designs are based on sheets of plywood which would


Powering them with solar also doesn't work. A massive solar array might produce 2-3hp during ideal conditions and substantially less in other conditions. Then even if the solar array could provide the power, the battery bank won't be able to store enough for any significant range unless you are happy with 2-3kt speeds and even then it's going to be very limited range.


Run the numbers. You can make it work to get in and out of a marina but after that, things go downhill quickly.
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Old 19-08-2016, 13:31   #53
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re: Why little popularity in pocket cruising catamarans?

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Originally Posted by PacificGreen View Post
I certainly am not advocating this from a green perspective per say. Yes there are elements that some might preclude to being part of some green movement or desire to market that way.

I'm not really concerned with how much energy it takes to provide raw materials for the smelting of aluminum. I am interested to know if the basic design of a Catalac, Bobcat, or Gemini could be mass produced quickly from aluminum minus all the obsolete sailing stuff in just a plain jane powered catamaran fashion? No, the cost of an alumnium boat this size would be far higher, as would the weight. Even after you remove the sailing hardware.

Kind of a loaded question there isn't it. IMHO densities of energy storage and solar return make sail and wind driven boats non essential for trans ocean IMHO. There just don't seem to be a huge ground swell of people doing it.Not true, the energy density of solar panels is not high enough to support reasonable trans-ocean crossings. Yes it's technically possible, but far far slower than a comparable sail boat.

Personally the overly complex maintenance schedule, high cost of outfitting and rigging to sail is what ultimately turn me off from going sail and wind. Know anyone that needs a brand new 42' aluminum extrusion? If anything all that should be required to propel with wind would be an easily maintainable affordable solid wing mast but then that is a project for another day.

I would assume strength wise composites are probably stronger or at least as strong as aluminum would be. If the weight could be drilled down on a basic model and mass produced then everyone would want one. That is the basic formula - mass produce quickly for affordable price and provide stable platform. Strength is almost never the issue in boat building, stiffness is. And stiffness comes with either a very complicated build using internal framing or very heavy plate. The first drives costs way up because you have lots of welding to do on a tempered alloy, the second drives up weight and cost because of the plate thickness.

All of this could be automated of course, but the robots to do it, and the forming machines would run in the tens of millions of dollars. You could never pay for them, even if the design became the most popular 30' boat ever.


Otherwise try finding pocket cruising catamaran for sale and end up with old school crap hanging off your boat that has to be removed before a proper conversion can take place.
Electric power is simply not dense enough to replace sails. The fastest trans-Atlantic electric crossing so far is Planet a Solar at an average speed of 5.3kn. While the current record holder averaged 33.94kn. To put this into context the planned crossing time of cargo ships in 1830 was 6kn. So at best the fastest solar powered ship in the world is only about 90% the speed that cargo ships were 225 years ago.
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Old 20-08-2016, 10:24   #54
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re: Why little popularity in pocket cruising catamarans?

Sorry but all else being equal a small aluminum cat will weigh more than a fiberglass version.
How much more that would be the question especially if the builder could make them quickly with the correct mounting and roof structure for the solar canopy.


Producing a Gemini, Catalac or similar hull from aluminum doesn't work because they were designed for fiberglass construction. Maybe a wharram as many of those designs are based on sheets of plywood which would
As my video alludes to I own a Bobcat and it has some basic wood stringer construction that would appear easy to replicate with aluminum like you say a wharram is. All the later catamaran designs followed these forerunners and evolved from there.

Powering them with solar also doesn't work. A massive solar array might produce 2-3hp during ideal conditions and substantially less in other conditions. Then even if the solar array could provide the power, the battery bank won't be able to store enough for any significant range unless you are happy with 2-3kt speeds and even then it's going to be very limited range.
Powering them with solar does work. I only have 2160 watts of solar on mine and find that quite adequate especially with range extender generators. The battery bank is where you must be still clinging to lead acid or AGM mentality. With 20kw/h stored at 48v nominal voltage in lithium batteries with generators and solar backing it up the generator serves only to keep them quite happy around 52.5 volts and the solar does the rest. So far as range I certainly don't have any anxiety over the range aspect that being almost unlimited.


Run the numbers. You can make it work to get in and out of a marina but after that, things go downhill quickly.
Okay then run the numbers again. 400ah usable daytime travel at 4 knots burning 20amps due to 20amp average input from panels I'm traveling for 20 amps. I can travel at 20 amps for 20 hours. So pretty much down the river to Stevenston and back up the river around the island on the Fraser and back to the dock in the evening without even having to fire up the generator. Much of the time even the current use was even not monitored or budgeted if I felt like wasting current I did and could burn 100 amps, 200 amps, 80 amps in spurts when I felt like it. Had I wanted to fire up a single dc generator I would have arrived back at dock still fully charged for the most part. I have upload the gpx track of the 17 nm trip if you want to view it in your opencpn or otherwise.

The trip for the most part was a real shakedown cruise the longest I had to date. It gave new meaning to the word shakedown and I didn't feel like having scrambled eggs from the fridge falling over. The current back up river was exceptionally strong around 4 or 5 knots but with 2 feet diameter of prop in the water we had no problem navigating right of way with the big tugs and smaller boats on the water that day.

Comparatively speaking we did see the typical 150 hp boat out there ripping around out there and for a 4 hour cruise burning at minimum 10 gph his price was 40 gallons of gas or 150 liters for a price in CAN$ of around $200.00 for the trip.
Attached Files
File Type: gpx track1.gpx (12.8 KB, 18 views)
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Old 20-08-2016, 11:13   #55
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re: Why little popularity in pocket cruising catamarans?

Electric power is simply not dense enough to replace sails. The fastest trans-Atlantic electric crossing so far is Planet a Solar at an average speed of 5.3kn. While the current record holder averaged 33.94kn. To put this into context the planned crossing time of cargo ships in 1830 was 6kn. So at best the fastest solar powered ship in the world is only about 90% the speed that cargo ships were 225 years ago.

transatlantic21: The world's first crossing of the Atlantic on a solar boat did the pacific in 90 days 7000 nm on solar only the brave souls in 2007 with lead acid batteries. The typical solar sailor of the future will neither run lead acid batteries or go without a generator. In terms of solar only sure but then you steer the discussion that way not me. I certainly would never venture far without a seldom used range extender (dc generator) in which case there is no problem increasing speed when wanted.

So far as cost of molds and high price I really don't see it. The biggest hurdle in solar adoption is having the boat designed right in the first place with the ability of having adjustable solar panels something I personally fought with during my outfitting.

Simply suggesting that with some patience a small multihull of wood frame construction could be copied quite easily with aluminum. When finished if the new aluminum catamaran weighed another 1000 lbs I don't think anyone would care if they had everything they were looking for in terms of battery storage and solar canopy. I mean I look at it all the time and it wouldn't appear that difficult to remake from aluminum and a competent welder could fab one together in a few weeks. I mean the original construction from wood was not out of the question from a time aspect in the sixties as they made many of them.

But more to the question of why small pocket cruising catamarans are not popular. Who wants the hassle of mast and sails? Who wants the high cost of petroleum products? Who wants to spend money maintaining engines and sails? Who in this day and age wants to cruise without all the comforts of home electrically speaking? Answering those questions is all I'm suggesting with a small business cranking out custom hulls and let the purchasers outfit how they like. There really is no range anxiety for a pocket cruising catamaran and for most the aspect of a solar electric catamaran might very well appeal to them more so than the options especially in 2016.
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Old 20-08-2016, 11:23   #56
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re: Why little popularity in pocket cruising catamarans?

PacificGreen:

It sounds like you've built what serves your purpose but there are a number of stumbling blocks trying to take what you've done and apply it to a production builder:
- I missed the size of your boat, which threw off my speed assumptions a bit but even so, it sure looks like your cruise speed is 4kts if you want any range. This is a common point of dispute. If you build a one off boat and accept lower speeds, that's fine. Try to sell a boat that has a cruising speed limit of 4kts, and it doesn't sell so well. Take that up to 5 or 6 kts which is what the buying public will expect and you just doubled or tripled the power consumption.
- You are essentially generating about 2.8hp peak (most of the day, it's much lower an at night nothing. 3hp might get a 26' cat up to 4kts. I really question the conditions if you are claiming 1.25hp (20amps at 48v) gets you 4kts. It's certainly questionable as you move into the 30'+ range.

But let's say you really are able to cruise for several hours per day at 4kts.
- At roughly $1/w for uninstalled sola panels - $2160
- 400amp-hr (at 48v) lead acid batteries - $2500 but you can't run lead acid more than 50% if you want them to last long so $5000 for 800amp-hr. Assuming 6v deep cycle, that's 1000lbs of batteries in a 26' boat. That eats up a lot of storage space.
- Lithium would save space and weight but jack up the cost even further.
- You still need to by at least 1 electric motor (looks like you have two). Let's be generous and say $2000 for an electric outboard so installation costs can be minimal.
- Misc wire, charge controller, etc... say another $500.

That totals up somewhere around $10k without installation costs. When we bought our gemini, we added a new 25hp outboard for $5k installed. In the 9yrs we had her (including 1.5 times around the great loop mostly under power), we haven't used $3k in fuel. Most owners won't even burn that much. For your boat and the speeds you are willing to live with, you could drop back to a 4hp outboard for something around $1500 (haven't priced them lately so maybe $2000) and if you cap the speed at 4kts, you are probably going to see 3-4times the fuel efficiency we saw drastically reducing fuel consumption. When talking about mass market appeal, that's a tough hurdle to overcome.

Remember, you built yours yourself, so you probably considered the labor to do all the installation fun time. Put a couple of guys that cost the builder $100hr (with overhead) and that's going to tack on a few thousand more to the cost of installing the drivetrain.

Reality is I suspect, something is off in the numbers you have shared. As mentioned, the record with a purpose built extreme boat is 5.3kts.

PS: The aluminum hull is a different discussion but its not the internal bulkheads that are difficult to fabricate. It's the complex hull shapes. It can certainly be done but unless you get into true mass production, it's tough to justify the hardware. There are some aluminum bass boats that are basically press formed but I believe they are looking at several thousand year not a couple hundred. If you are talking about bending sheets of aluminum into complex shapes by hand and welding them together, it takes time and skill. Much easier to do fiberglass in a mold with guys of moderate skill. That's why I suggested a wharram type design as the hull is a simple V shape, so it's relatively easy to form out of sheets. The downside is they are not the most efficient hulls.
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Old 20-08-2016, 18:51   #57
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re: Why little popularity in pocket cruising catamarans?

Sorry Pacific but I don't think your boat is what this thread is about.


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Old 20-08-2016, 20:05   #58
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re: Why little popularity in pocket cruising catamarans?

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Sorry Pacific but I don't think your boat is what this thread is about.
Now your stating the obvious there and obviously trolling for something you wont get from me. You can retract. I've only tried to come up with alternatives as to why or how smaller cruising catamarans might be a more viable solution for boaters.

I've approached the thread with optimism and enthusiasm with a lot of creative thinking. To that end I will agree in this day and age all things considered literally smaller cruising catamarans are not a viable economic choice for any number of reasons cited by the contributors. They will however remain popular with myself and those lucky enough to have found a place in there life for one.
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Old 20-08-2016, 20:12   #59
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re: Why little popularity in pocket cruising catamarans?

I am not trolling I am trying to keep this thread on topic, I appreciate your contribution and am enthusiastic about the technology you are supporting.
This thread however is under Multihull Sailboats, which you clearly have no interest in. So I would suggest if you want to explore your topic further you take it to powered boats which yours clearly is.
Best Wishes.
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Old 20-08-2016, 20:31   #60
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re: Why little popularity in pocket cruising catamarans?

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PacificGreen:

It sounds like you've built what serves your purpose but there are a number of stumbling blocks trying to take what you've done and apply it to a production builder:
- I missed the size of your boat, which threw off my speed assumptions a bit but even so, it sure looks like your cruise speed is 4kts if you want any range. This is a common point of dispute. If you build a one off boat and accept lower speeds, that's fine. Try to sell a boat that has a cruising speed limit of 4kts, and it doesn't sell so well. Take that up to 5 or 6 kts which is what the buying public will expect and you just doubled or tripled the power consumption.
In the end if you have a small generator as a range extender is doesn't much matter.

- You are essentially generating about 2.8hp peak (most of the day, it's much lower an at night nothing. 3hp might get a 26' cat up to 4kts. I really question the conditions if you are claiming 1.25hp (20amps at 48v) gets you 4kts. It's certainly questionable as you move into the 30'+ range.
Well if you watch the videos it is pretty plain as day to see the solar input at 17amps or 11 amps depending on which video and the output of 40 amps. Subrtract.
But let's say you really are able to cruise for several hours per day at 4kts.
- At roughly $1/w for uninstalled sola panels - $2160
- 400amp-hr (at 48v) lead acid batteries - $2500 but you can't run lead acid more than 50% if you want them to last long so $5000 for 800amp-hr. Assuming 6v deep cycle, that's 1000lbs of batteries in a 26' boat. That eats up a lot of storage space.
Lead is dead. Think lithium 20kw/h @ 48 volts. 535 lbs.
- Lithium would save space and weight but jack up the cost even further.
20kw/h lithium $10000 deliverd more or less these days. Can't imagine it being possible without
- You still need to by at least 1 electric motor (looks like you have two). Let's be generous and say $2000 for an electric outboard so installation costs can be minimal.
- Misc wire, charge controller, etc... say another $500.

That totals up somewhere around $10k without installation costs. When we bought our gemini, we added a new 25hp outboard for $5k installed. In the 9yrs we had her (including 1.5 times around the great loop mostly under power), we haven't used $3k in fuel. Most owners won't even burn that much. For your boat and the speeds you are willing to live with, you could drop back to a 4hp outboard for something around $1500 (haven't priced them lately so maybe $2000) and if you cap the speed at 4kts, you are probably going to see 3-4times the fuel efficiency we saw drastically reducing fuel consumption. When talking about mass market appeal, that's a tough hurdle to overcome.
I'll give you that it is a tough hurdle to beat but is a pretty easy sale when you consider the upside of all the energy produced and the creature comforts available. I mean all things considered I have a new 9.9 yamaha high thrust barely broken in but wouldn't consider it for actual motive power on the boat.
Remember, you built yours yourself, so you probably considered the labor to do all the installation fun time. Put a couple of guys that cost the builder $100hr (with overhead) and that's going to tack on a few thousand more to the cost of installing the drivetrain.

Reality is I suspect, something is off in the numbers you have shared. As mentioned, the record with a purpose built extreme boat is 5.3kts.
Now if you can or have viewed the track in opencpn or other wise I don't see how you can state the numbers are off at all. The gpx track comes directly from my AIS and GPS sensors on the boat. It was no problem doing more than 5.3 knots for extended periods and likely during those times current was also helping which is to be expected. The track doesn't lie it is what it is.
PS: The aluminum hull is a different discussion but its not the internal bulkheads that are difficult to fabricate. It's the complex hull shapes. It can certainly be done but unless you get into true mass production, it's tough to justify the hardware. There are some aluminum bass boats that are basically press formed but I believe they are looking at several thousand year not a couple hundred. If you are talking about bending sheets of aluminum into complex shapes by hand and welding them together, it takes time and skill. Much easier to do fiberglass in a mold with guys of moderate skill. That's why I suggested a wharram type design as the hull is a simple V shape, so it's relatively easy to form out of sheets. The downside is they are not the most efficient hulls.
The aluminum hull construction actually addressed the OP's question correctly and the resulting discussion was recorded with valid viewpoints as to outfitting for what might make a popular catamaran and what may not.
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