Hi Chris. I think this is an absolutely beautiful idea. I have been thinking along these lines for a long time. I desperately wanted diesel outboards for my catamaran, but could not find anything remotely suitable.The advantages of this mid-bridgedeck long-tail arrangement are many: Compared to outboard motors, with this arrangement you get the economy of diesel, the battery charging capability of a full alternator, can put a big pushing propeller on the engine and put the propeller as deep in the water as you wish to have it. The central weight distribution is also better than the normal aft-engine arrangement. The regular marine gearbox that you use on the engine is a lot cheaper than the sail-drives that are normally used on catamarans.And then you get most of the advantages of outboards - you can lift the prop out the water when you are sailing or at anchor, you can drop the engine off the boat for major work without having to pull the boat out the water (although with a cat you can beach it reasonably easily anyway - but still on conventional diesel installations prop and shaft work has to be done between tides) and there are fewer holes in the hulls - just need a through-hull if you wish to suck the cooling water up through the hulls. Unfortunately the layout of my bridgedeck and saloon was already done and did not allow for an easy conversion to this arrangement of engines. But glad to see that someone has actually done it this way.CheersAndrew
Wednesday, February 29, 2012
Re: [Electric Boats] Re: Newbie Question- Converting a 45' catamaran
Re: [Electric Boats] Re: Newbie Question- Converting a 45' catamaran
Andrew did you google the Yanmar D27/D36 you can still bet NIB's and SH up to 50 hours
Andrew
On 2/29/2012 5:23 AM, And&Hanna wrote:
Hi Chris. I think this is an absolutely beautiful idea. I have been thinking along these lines for a long time. I desperately wanted diesel outboards for my catamaran, but could not find anything remotely suitable.The advantages of this mid-bridgedeck long-tail arrangement are many: Compared to outboard motors, with this arrangement you get the economy of diesel, the battery charging capability of a full alternator, can put a big pushing propeller on the engine and put the propeller as deep in the water as you wish to have it. The central weight distribution is also better than the normal aft-engine arrangement. The regular marine gearbox that you use on the engine is a lot cheaper than the sail-drives that are normally used on catamarans.And then you get most of the advantages of outboards - you can lift the prop out the water when you are sailing or at anchor, you can drop the engine off the boat for major work without having to pull the boat out the water (although with a cat you can beach it reasonably easily anyway - but still on conventional diesel installations prop and shaft work has to be done between tides) and there are fewer holes in the hulls - just need a through-hull if you wish to suck the cooling water up through the hulls. Unfortunately the layout of my bridgedeck and saloon was already done and did not allow for an easy conversion to this arrangement of engines. But glad to see that someone has actually done it this way.CheersAndrew----- Original Message -----From: chris BakerSent: Tuesday, February 28, 2012 5:33 AMSubject: Re: [Electric Boats] Re: Newbie Question- Converting a 45' catamaran [1 Attachment]Hi Sean
Here's an idea that may help you keep the props out of water, and be easy to build from off the shelf parts...
This idea is from Owen Easton, a cat designer/builder downunder. Its kinda like the long tail boats in Thailand where you have the prop on the end of a long shaft that hangs out the stern of the boat. But on a cat you can use this idea between the hulls. The motor is amidships for good weight positioning and the props fold up towards the centreline of the boat under the bridge deck. In owen's designs the powerplant has been two ICE engines driving this prop shaft through a universal joint.
I have some photos of this setup and will put them up soon when I take a look at how to do that. I'll paste a photo here but I expect it may not show up.
-- AJ Gilchrist Fastelectrics 0419 429 201
[Electric Boats] Re: motoring with ,quickcharge 48/V 25 amp,6V agms,and a honda 2000
I'm rather late to the discussion, but I thought I'd mention that there is an easy way to know if the Honda EU2000i has shut off its AC output, even though it remains running.
As Mike mentioned, in normal operation there is no obvious indication that the AC output is shut down (unless you are looking at the front of the generator).
If the "ECO" operation mode is switched on, the generator engine rpm varies with the load on the generator. When overloaded, the engine returns to idle. Then you'll know to look for the little red light.
Works for me.
-Tom
--- In electricboats@yahoogroups.com, Mike <biankablog@...> wrote:
>
> The only thing I would add about running the generator close to the edge of it's current capacity is be aware of what happens when it trips. I found this out on a cruise recently:
> http://biankablog.blogspot.com/2011/03/lesson-learned-fear-and-panic-in-east.html
> It was puzzling at first until I realized what had occurred. When the Honda 2000 generator trips it does not shutdown. Unless you are paying real close attention you might not even know that the breaker has tripped. The Honda will keep running but, won't be providing power. So it could lull you into a sense that you think you are motor sailing with it. When in fact you are actually just draining down your battery bank. I'm not sure if other generators operate the same way. Just be aware when you are operating close to the limits of your generator how it behaves when it trips. Check the breaker for a trip or a fault light.
> Â
> Capt. Mike
> http://biankablog.blogspot.com
> Â
>
>
> ________________________________
> From: Eric <ewdysar@...>
> To: electricboats@yahoogroups.com
> Sent: Monday, February 27, 2012 8:58 PM
> Subject: [Electric Boats] Re: motoring with ,quickcharge 48/V 25 amp,6V agms,and a honda 2000
>
>
> Â
> I'll assume that you're talking about a Quickcharge SCO4825 Select a charge on-board charger. On their website they provide the following specs, 48V, 25A, 12A@117VAC. If all this is true, then I don't see a problem. But I don't believe these numbers.
>
> Lets look at the energy input, 12A x 117V = 1404W. That's easy enough.
>
> You know that your 6V batteries don't charge at 6V, the peak charge voltage for your AGM batteries is 7.2-7.3V. So your peak pack charging voltage for 8 batteries in series is 57.6V. Let's call it 54V for the bulk of your charging. 25A @ 54V = 1350W. The Quickcharge website doesn't mention the technology that they use, but at the bottom of their promotional PDF, they mention "100% copper transformer heavy duty rectifiers..." These types of chargers have traditionally operated at 80-85% efficiency. So being generous, 1350W output will take only 1600W input (assuming 85% efficiency). 1600W/117V = 13.7A. Not a big deal you say, it's only a difference of 1.7A, but let's read on.
>
> Now let's look at your generator. A Honda eu2000i is rated for 1600W continuous output, so now you're right on the line. If your charger only pulls 13.7A while charging, you're good. But it might pull more. If it does, your Honda will shut itself down when the load getts too high. My Yamaha 2000 will do the same.
>
> Maybe the SCO4825 only puts out 1200W (48Vx25A), if so, then the output at 54V will be around 22A. If that is the case, then the Honda should handle it fairly well, but you won't be getting 25A.
>
> If you have access to one of these chargers, then the simple way to check it's power requiremetns is to run it through a Kill-A-Watt meter while charging your batteries. I have a P3 model, they are available at Radio Shack for less than $30. If you don't have access to the charger, you have to take the manufacturer's word, but their published specs are suspicious to me. At almost $500, that could be an expensive experiment. Of course, if you buy it somewhere with a good return policy, your risk is lower.
>
> I went through the same debate and I chose an Elcon PFC2000+ charger for around $600. The manufacturer specs were more believable and they were able to load a charging profile that was perfect for my LiFePO4 battery pack, AGMs are even simpler. My measured thoughput effieincy is close to 93% with the fully electronic (no transformer) PFC charger. Elcon's spec of 14A@115V nominal input turned out to be right on (as measured with a Kill-A-Watt monitor)during the bulk charge phase for my batteries. This 14A exceeds my Yamaha generator's continuous rating of 13.7A, but I've run the charger for an hour from the generator and it hasn't missed a beat, I would expect the same from a Honda. I've also verified that I'm getting a consistant 27-28A at 55V from the charger/generator combo. This powers my 30' 10,200 lb boat at 4.2-4.3kts without using any battery at all.
>
> Most of the other peoplpe in this group that have electro-motored on their portable generator (Myles, Mike, etc.) are running chargers with lower input/output so their generators are not as close to the limits. So your proposed setup might work, and it might not.
>
> After all of this work, I've never had to use my generator to get home. I motored the boat for an hour on the generator as a proof of concept, and it worked fine, but I've never needed it in real life.
>
> Perhaps someone else in the group has more hands on experience with the specific charger that you're looking for. If so, hopefully, they'll jump in.
>
> Fair winds,
> Eric
> 1964 Bermuda 30 ketch, 5.5kW Propulsion Marine drive, 8kWh Lithium batteries
> Marina del Rey, CA
>
> --- In electricboats@yahoogroups.com, "Bill Falk" <fsailing35@> wrote:
> >
> > anyone using this set up? if so how is it working for you and what charge settings are you using? any info thanks
> >
>
Re: [Electric Boats] Re: PMAC gear reduction
Andrew, sorry I don't have any throttle setting or fuel flow data. Just to clarify, I was at 856 RPM at 7 Knots. Chris --- On Wed, 2/29/12, Andrew Gilchrist <andrew@fastelectrics.com> wrote:
|
[Electric Boats] Re: GPH to power formula
Hi Andrew,
I think I know where you're going with the throttle setting question, but throttle on an ICE is rarely linearly correlated with power output. I found that looking at fuel consumption (which some regular people track in their boats) is a better gauge of power setting.
The simple formula that I use is (Gallons Per Hour * Thermal Efficiency)/Fuel Constant = HP or (GPH * TE)/FC = HP. This should give you shaft power at the flywheel.
The fuel constant is 0.0226 for gasoline and 0.0197 for diesel. The thermal efficiency is your guess, but for all but peak settings, you can pretty much count on 25% or less from most marine inboards. At very low throttle settings, the TE(including accessory losses) may be as low as 10%.
At cruising speeds with my old diesel, she burned about 0.5 GPH. Using 0.25 for thermal efficiency in the (GPH * TE)/FC, we get (0.5 * 0.25)/0.0197 = 6.3hp. That thermal efficiency might be a little optimistic at partial throttle settings with the old one cylinder, so my power output was probably less at those burn rates. At full throttle, she burned 0.9 GPH. (0.9 * 0.25)/0.0197 = 11.42, the engine was Yanmar SVE12 12hp model. Using 0.265 for the TE makes the calculation come out to 12hp. So this sounds reasonably accurate. Of course, using small numbers increases the chance of inaccuracies due to measuring variances, but I've done the same calcs for a large cabin cruiser and the numbers matched up with the engine manufacturer power specs at cruising speeds.
Anyway, I thought that you might like another formula to add to your bag of tricks. I've used this one in this group to explain the difficulties of convering large cabin cruisers, ski boats and houseboats to electric. It's surprising the number of people that actually know their fuel usage, that makes the conversation easier.
Fair winds,
Eric
Marina del Rey, CA
PS. This is off-topic: Try doing the math for a car that gets 45mpg at 60mph (1.33gph). With a 35% thermal efficiency, you only get 20hp to overcome all the wind and rolling resistance. Since you don't want to be running the engine at peak efficiency RPM (3500-4000 rpm?) while cruising at 60mph, the problem gets pretty tough. This makes my simple old 1990 Geo Metro that got 52mpg averaged over 130,000 miles pretty impressive. They don't make 'em like that anymore... ;)
--- In electricboats@yahoogroups.com, Andrew Gilchrist <andrew@...> wrote:
>
> Chris
>
> i will look forward to hearing about the prop
>
> BTW why is electric your only option?
>
> when you did that test that got you 825prop rpm for the 7 knots on the
> diesel can you remember your throttle setting?
>
> all the best
>
> Andrew
>
Re: [Electric Boats] Re: PMAC gear reduction
Chris
i will look forward to hearing about the prop
BTW why is electric your only option?
when you did that test that got you 825prop rpm for the 7 knots on the diesel can you remember your throttle setting?
all the best
Andrew
On 3/1/2012 12:41 AM, Chris Hudson wrote:
Andrew,
alas I don't know what prop I have. I've owned the boat less than a year. I'll be having a diver go down to clean soon and will have him see if he can see the numbers.
Chris
--- On Wed, 2/29/12, Andrew Gilchrist <andrew@fastelectrics.com> wrote:
From: Andrew Gilchrist <andrew@fastelectrics.com>
Subject: Re: [Electric Boats] Re: PMAC gear reduction
To: electricboats@yahoogroups.com
Date: Wednesday, February 29, 2012, 1:09 AM
Eric
I had your speed wrong thanks
I'll wait and see what Chris' prop is
I agree Hp isn't an issue. However I think torque/amp is. Combined with HV that means a much better system and if the load can be reduced on the packs better voltage and deeper discharge levels (up to a point).
Then there is the issue of prop efficiency. The only area where this has been tackled is in variable pitch ship props and submarines. Putting these onto models and data logging shows how poor the clover leaf style props are and how all props have a very definite range of rpms over which they perform efficiently.
got to do some work
Andrew
On 2/29/2012 3:36 PM, Eric wrote:Hi Andrew,
Chris is trying to move more than 2.5 times the displacement, he's 13.5 ton and I'm 5.1. He's only looking for one extra knot, usually one knot faster costs roughly twice the power (and one knot slower takes about half the power). That rule seems to quit if one tries to push past 90% of hull speed. The power graph gets much steeper there. But along with Chris' greater displacement, he's got a longer waterline, so it takes less power to cruise at electric boat speeds.
But what I've noticed for similar types of boats (roughly the same hull form, for auxilary sailboats they are generally pointed in front, fat in the middle and narrow in back, with the widest part 30-40% of the length) our rule of 1kW per ton delivers about 90% of hull speed. That rule seems to work for sailboats from 25 to 40 feet, and may go farther, but we haven't had many bigger conversions report their performance.
Anyway, even with a much larger boat I would guess that his boat will pull around 6500W - 7000W at 6kts compared to my 5100W, just 30% more power to drive almost 3 times the mass. And these are conservative estimates, he might do better... The extra waterline really helps. That extra waterline also makes 7kts possible with reasonable power levels. I don't think that 20kW would push my boat to 6.5kts, that's too close to my hull speed.
All this comes from a variety of boats with different props and motors, as long as they've got the proper reduction to match the motor to the prop. Lower ratios to spin flatter, smaller props faster; higher ratios for bigger, more aggressive props. But they all seem to perform within 10-15% of each other. Of course, 10% is worth a little extra planning, at least to me.
Fair winds,
Eric
Marina del Rey, CA
--- In electricboats@yahoogroups.com, Andrew Gilchrist <andrew@...> wrote:
>
> Chris
>
> Thanks for that reference â€" ME were using it too.
>
> at 2.57 ratio and 856 prop speed the diesel was turning 2200rpm. Perkins
> spec sheets indicate at those rpm the motor could put out up to 55 shaft
> hp â€" and estimated torque of 131*2.57 = 337ft pounds. At part throttle
> who knows...
>
> Your boat displacement how does that compare to Erics? and the prop what
> are its diam pitch and number of blades?
>
> I think you may need way more power - you are (if memory serves) trying
> to propel twice the displacement (needs twice the torque) at twice
> the velocity (usually needs 8 times the power and commensurate torque)
>
> My thought is you need a larger motor with much higher torque per/ amp
> yield and a larger diameter at least and keep the g/box you have that
> ratio will come in handy.
>
> Need to know a bit more about throttle setting at 7 knots - if possible
> how fast at 100% throttle and prop dimensions, blade shape helps
>
> Andrew
>
>
>
-- AJ Gilchrist Fastelectrics 0419 429 201
-- AJ Gilchrist Fastelectrics 0419 429 201
Re: [Electric Boats] Re: PMAC gear reduction
Andrew, alas I don't know what prop I have. I've owned the boat less than a year. I'll be having a diver go down to clean soon and will have him see if he can see the numbers. Chris --- On Wed, 2/29/12, Andrew Gilchrist <andrew@fastelectrics.com> wrote:
|
Tuesday, February 28, 2012
Re: [Electric Boats] Re: PMAC gear reduction
Eric
I had your speed wrong thanks
I'll wait and see what Chris' prop is
I agree Hp isn't an issue. However I think torque/amp is. Combined with HV that means a much better system and if the load can be reduced on the packs better voltage and deeper discharge levels (up to a point).
Then there is the issue of prop efficiency. The only area where this has been tackled is in variable pitch ship props and submarines. Putting these onto models and data logging shows how poor the clover leaf style props are and how all props have a very definite range of rpms over which they perform efficiently.
got to do some work
Andrew
On 2/29/2012 3:36 PM, Eric wrote:
Hi Andrew,
Chris is trying to move more than 2.5 times the displacement, he's 13.5 ton and I'm 5.1. He's only looking for one extra knot, usually one knot faster costs roughly twice the power (and one knot slower takes about half the power). That rule seems to quit if one tries to push past 90% of hull speed. The power graph gets much steeper there. But along with Chris' greater displacement, he's got a longer waterline, so it takes less power to cruise at electric boat speeds.
But what I've noticed for similar types of boats (roughly the same hull form, for auxilary sailboats they are generally pointed in front, fat in the middle and narrow in back, with the widest part 30-40% of the length) our rule of 1kW per ton delivers about 90% of hull speed. That rule seems to work for sailboats from 25 to 40 feet, and may go farther, but we haven't had many bigger conversions report their performance.
Anyway, even with a much larger boat I would guess that his boat will pull around 6500W - 7000W at 6kts compared to my 5100W, just 30% more power to drive almost 3 times the mass. And these are conservative estimates, he might do better... The extra waterline really helps. That extra waterline also makes 7kts possible with reasonable power levels. I don't think that 20kW would push my boat to 6.5kts, that's too close to my hull speed.
All this comes from a variety of boats with different props and motors, as long as they've got the proper reduction to match the motor to the prop. Lower ratios to spin flatter, smaller props faster; higher ratios for bigger, more aggressive props. But they all seem to perform within 10-15% of each other. Of course, 10% is worth a little extra planning, at least to me.
Fair winds,
Eric
Marina del Rey, CA
--- In electricboats@yahoogroups.com, Andrew Gilchrist <andrew@...> wrote:
>
> Chris
>
> Thanks for that reference â€" ME were using it too.
>
> at 2.57 ratio and 856 prop speed the diesel was turning 2200rpm. Perkins
> spec sheets indicate at those rpm the motor could put out up to 55 shaft
> hp â€" and estimated torque of 131*2.57 = 337ft pounds. At part throttle
> who knows...
>
> Your boat displacement how does that compare to Erics? and the prop what
> are its diam pitch and number of blades?
>
> I think you may need way more power - you are (if memory serves) trying
> to propel twice the displacement (needs twice the torque) at twice
> the velocity (usually needs 8 times the power and commensurate torque)
>
> My thought is you need a larger motor with much higher torque per/ amp
> yield and a larger diameter at least and keep the g/box you have that
> ratio will come in handy.
>
> Need to know a bit more about throttle setting at 7 knots - if possible
> how fast at 100% throttle and prop dimensions, blade shape helps
>
> Andrew
>
>
>
-- AJ Gilchrist Fastelectrics 0419 429 201
Re: [Electric Boats] Re: ASMO Marine is now Clean e¯Marine
Thanks Eric! We are pretty excited about the growth and our new role in all of this! AHM is still a Regional Dealer and you'll see us at boat shows around the country. In fact, we'll be at Strictly Sail Pacific next month. Stop by and say hello if you are at the show. I would love to meet you in person!
Congratulations Sally!
I'm looking forward to hearing more about the new systems when they become available.
Fair winds,
Eric
Marina del Rey, CA
--- In electricboats@yahoogroups.com, Sally Reuther <smreuther@...> wrote:
> ... Moving forward, Clean e¯*Marine* will be offering additional systems using AC motors in> of the products for the North American market. This company, Clean e¯*Marine
> sizes up to 22kW for the pleasure boat market and larger systems for custom
> designs and commercial uses. The growth of the company has prompted the
> formation of a new distributing company which will handle all distribution
> Americas*, is based in Annapolis, MD and is currently busy setting up> Clean e¯*Marine Americas*
> Regional Dealer/Distributors throughout North America. For more information
> you can visit the website: www.c-e-marineamericas.com/news.php where
> updates will be posted in the coming weeks.
>
> Sally Reuther, CEO
> Ken Harrington, COO
> David DiQuinzio, CTO
>