Electric and Diesel comparison

[mikereed100]

I was regional power lounging champion for many years until I left competition to pursue the fledgling sport of extreme lounging. It is with some authority that I can confirm that beanbags and hammocks are indeed the best way to lounge.

When I tore out the interior of my Seabird Yawl to do some hull repair I replaced the "furniture" with beanbags. Not only were they a great place to lounge but also the best place to sleep when it got rough. Plus you can take them up on deck and drop them just about anywhere. A great way to take advantage of a multihull's deck space.

In regards to hammocks, one of the main reasons I wanted a cat was so I could hang a hammock in the cockpit. There will even be space in one of my hulls dedicated to a small hammock. One of the advantages to a custom build as opposed to production. Have fun with the new boat!

Mike

[cat man do]

Originally Posted by gosstyla

Thanks Mike.

Plan to spend a lot of time in Caribbean, especially around Bocas del Toro - therefore the crows nest.

Beanbags and hamocks are my favorite way to lounge.

And they are so light, and the bean bag's can be stuffed in large areas ti stop stuff rolling around if required.

In OZ for a while they had a bean bag that was made from a light cloth that dried fast, and these were great to lounge around in the water having a cleansing ale, or a rum or three.

Dave

[gosstyla]

Re: Hammocks

I've had 2 sets of padeyes installed in the saloon for hooking up hammocks. In addition to having several nooks on deck where they can hang.

[masalai]

Whimsical (Mike),
I just joined and had to express my appreciation and gratitude for the information posted so far (up to post 23) and may contribute some, if I may, Icecat - Excess Crew Project is of Robin Chamberlins activities - the motor yacht "Foreign Affair" may have been the story on diesel powered fuel efficiency.

In the "Summary" page are the figures - averaging 1.292 litres per nautical mile at 13.76 knots for a stink boat.... There is your challenge but the boat was designed for that level of efficiency
Best, Brian

[masalai]

gosstyla, I had difficulty in accessing your website, Runnung Linux/Mozilla Firefox shouldnt make any difference as I got the gosstyla page but not the link to your data, I would appreciate the info.
Thanks Brian

[gosstyla]

masalai:
http://www.gosstyla.com/Asanagi

should do it, hasn't been updated for a while.

[masalai]

Thank you very much, Had a quick read, will peruse in detail as time goes by...
Brian

[fastcat435]

Originally Posted by Whimsical

Bret
"Waypoint had a motoring voltage of 146. You cannot use 50A per motor to convert to KW as 100A is the maximum current of both shafts combined."
But you can say that Waypoint has a total power of 14 kW or 570 kg/kW, if the weight is correct. The diesel 410 has 60 hp which suggests 20 hp equates to about 4.5 kW. This adds credence to Re-e-powers claims and detracts from Frey.

Hallo Whimsical
What propulsion power have you chosen for your new Schionning 12.3 cat
Just curious

Greetings
Gideon

[Whimsical]

Gideon
I came to the conclusion that for equivalence electric should be rated at about 70% of diesel. That is, in my case, about 9 or 10 kw to replace 20hp, this is assuming a shaft speed around 1000 rpm versus around 1700 for the diesel. I feel this is where the electric gains its apparent superiority and if diesels could turn much slower the differences would be much smaller.
From the limited data I could collect I feel that most electric instalations may be fine in calmer conditions but when **** hits the fan most are lacking and Frey's ratios are more appropriate.
Given the above and looking at wieghts and costs I could not, for me, justify electric. I went with the lightest option available in diesel being a pair of 20hp Lombardinis.
The cost of established components, eg gen set, is so outlandish that the difference even with astronomical costs for diesel would take to long to recoup.
I wish I had the time and money to build versions with both to do extensive testing and once and for all establish some concrete evidence to support a true equivalence. I would hope that it would come out in favour of electric but at this point in time the available evidence does not seem to support it. I feel a diesel electric would be the best option at this point in time until batteries such as the valence come in at a respectable price enabling a substantial bank. I would then switch allegience to a proper hybrid.
Just a thought for your green motion drives. It is a pity that you have not opted for steerable drives as then we could have vectoring thrust which would open the possibilities for some real fun in developing some unique handling on sailing cats, alla the Volvo system.
Maybe by the time I am ready for my next boat electric may be advanced to the point where I could not resist. Either that or I could get a job as a new technology development person and realy get stuck into exploring the possabilities.

Mike

[fastcat435]

Originally Posted by Whimsical

Gideon
I came to the conclusion that for equivalence electric should be rated at about 70% of diesel. That is, in my case, about 9 or 10 kw to replace 20hp, this is assuming a shaft speed around 1000 rpm versus around 1700 for the diesel. I feel this is where the electric gains its apparent superiority and if diesels could turn much slower the differences would be much smaller.
From the limited data I could collect I feel that most electric instalations may be fine in calmer conditions but when **** hits the fan most are lacking and Frey's ratios are more appropriate.
Given the above and looking at wieghts and costs I could not, for me, justify electric. I went with the lightest option available in diesel being a pair of 20hp Lombardinis.
The cost of established components, eg gen set, is so outlandish that the difference even with astronomical costs for diesel would take to long to recoup.
I wish I had the time and money to build versions with both to do extensive testing and once and for all establish some concrete evidence to support a true equivalence. I would hope that it would come out in favour of electric but at this point in time the available evidence does not seem to support it. I feel a diesel electric would be the best option at this point in time until batteries such as the valence come in at a respectable price enabling a substantial bank. I would then switch allegience to a proper hybrid.
Just a thought for your green motion drives. It is a pity that you have not opted for steerable drives as then we could have vectoring thrust which would open the possibilities for some real fun in developing some unique handling on sailing cats, alla the Volvo system.
Maybe by the time I am ready for my next boat electric may be advanced to the point where I could not resist. Either that or I could get a job as a new technology development person and realy get stuck into exploring the possabilities.

Mike

Hallo Mike

I think you have made the right choice taking the high cost of diesel electric drives in to account. I feel that 7 Kw electric motors would do the job , also in stormy conditions.
We have the steerable motors as an option but it ads a lot of weight and you know how i feel about weight !!!!.
Their is no lighter weight motorization than the Lombardini,s you have chosen.
If I where you I would opt for the larger alternators of 100 amps each side and electrical stop function, a small price to pay for a lot of extra watts.

When do you expect to be sailing ?

Greetings

Gideon

[Whimsical]

Gideon
They wanted to much for the bigger alts so I will add them myself. They came with the electric stop as standard and they threw in the 3 gauge analogue display. I hate the digital display with the membrane keyboard as I come from an electronics background where these were prolific and regularly died within a couple of years. I would expect to be building for at least another 12 months. My hours are limited as I am a single dad with a 5 year old.
Steerable and retractable could be a dificult combo. I tend to be wieght obsessed like you

Mike

[fastcat435]

Originally Posted by Whimsical

Gideon
They wanted to much for the bigger alts so I will add them myself. They came with the electric stop as standard and they threw in the 3 gauge analogue display. I hate the digital display with the membrane keyboard as I come from an electronics background where these were prolific and regularly died within a couple of years. I would expect to be building for at least another 12 months. My hours are limited as I am a single dad with a 5 year old.
Steerable and retractable could be a dificult combo. I tend to be wieght obsessed like you

Mike

Let me know if you need light weight dyneema netting for your trampoline when you get close to finishing. We have this manufactured for our cats.
Anything else I can help with let me know

Greetings and good luck with the building of the cat
Gideon

[gosstyla]

Originally Posted by Whimsical

Gideon
I came to the conclusion that for equivalence electric should be rated at about 70% of diesel.
Mike

I believe that is a good estimate for the most efficient electric systems currently available.

My 35hp electric motors were powered by 25KW gensets which were powered by 45hp Mercedes diesels. I could not make direct objective comparisons however subjectively I felt my 47ft cat's performance was not significantly different that it would have been powered directly by the diesels.

[fastcat435]

These comparisons depend a lot on how efficient the generators , electric motors etc are
A drive shaft for instance can take as much as 10 % power away. A slow revving prop can be 20 % more efficient than a high revving one.
If a prop is mounted on the front of an electric motor that can make as much as 15 % difference in efficiency. adding all these possible reductions in efficiency up could halve the actual power used to propel and that could reduce the size of motors used .

Greetings

p.s. it will always be hard to compare apples and pears unless 2 identical boats with the same weights are equipped with diesel versus hybrid.
I am sure that Lagoon with the 420 should have these comparisings available and we will have this at the end of this year .
The main issue is off course

how much fuel is used with thew diesel version and how much is used with the lectric hybrid version at identical speeds.

[henryv]

There is some very good analysis of comparative performance between conventional and hybrid drives at the Hybrid-Marine web site:http://www.hybrid-marine.co.uk/resou...evaluation.pdf