How much electric power is needed to power a 40 - 45' cat at 5 knots?

Originally Posted by LtBrett

ummm...

Island Pilot DSe Home Page

Brett

Brett,

uuuummm....

You're joking right? That's not a solar powered boat. It is a boat that has solar power cells tacked on.

Did I really need to say "powering a boat only with solar power isn't even theoretically possible for the foreseeable future."

[Blue Skye]

E motion Hybrids Home

Seems like they have been doing it for a while, just down the road from me. Having a genset seems to be required unless you don't mind hanging loose for a few days while you charge.

I don't get the crawl off lee shore argument. I may not see the whole picture but, from my limited research it seems as if the electric delivers more torque to similar and even larger props . Certainly would need the generator in those conditions....

[fastcat435]

Originally Posted by Blue Skye

E motion Hybrids Home

Seems like they have been doing it for a while, just down the road from me. Having a genset seems to be required unless you don't mind hanging loose for a few days while you charge.

I don't get the crawl off lee shore argument. I may not see the whole picture but, from my limited research it seems as if the electric delivers more torque to similar and even larger props . Certainly would need the generator in those conditions....

Dave Tether the owner of e Motion is the founder of Solomon Tech. and knows his business.
He relies mostly on regenerative power and the use of backup generators.
I feel that specially on a catamaran it is possible to install enough solar and wind power , combined with the latest Lithium Ion Phosphate batteries to store enough power that a generator is not necessary unless you are in a hurry.
We install up to 2300 Wp of solar power on a FastCat 435 plus 1 or 2 wind generators adding up to 600 watt per hour.
In a average day we get as much as 20 KW in or enough to run one motor in excess of 6 hours at an efficient setting, when the sun is out and wind is available one motor can run at slightly higher than the extreme efficient setting adding speed to the FastCat 455 otherwise this energy is wasted anyway.
I believe that what we have created in terms of efficiency is the best but at a cost.

Gideon

[KHK007]

Hi everybody,

Just to make clear:

I'm probably a little bit ahead of technology.

Yes, it's supposed to a kind of stunt and I'm aware that I'll not beat any circumnavigation sailing record done under sails. I'll alos stay in area where there is a lot of sunshine. So, I'm not going around Cape Horn.

If there is no sun, I'll have to wait for it if running out of battery energy. That's a little bit like an (ocean) saling race where the guys are not allowed to use their engine: What do they do if there is no wind? They wait for it...

It will not be possible to make sails of silicon solar cells because they might break and can not be folded. Maybe there will be more flexible organic or other solar cells one time, but not at the moment. And the solar cell in sails would not be well exposed towards the sun around noon when there is the maximum energy available...

Anyway, I know now it's possible as a stunt, I just need to be patient as I will depend on weather like sailors and figure out which is the best cat and the best propulsion system...

Greetings from Paris,

Kai

[cat man do]

Eleven;
Interesting that the old Snowgoose 37 with it's standard 27hp is listed somewhere on these threads as doing 18kn under power.

Cough (********) Cough

8 maybe

I'm doing a light 50 footer with a 12.5:1 BWL with 65hp a side and only expect 14knots on the fly on a good day

Dave

[fastcat435]

Somebody with a Snowgoose needs to get his log ( or his head ) recalibrated even 8 is almost impossible with 2 x 27 Hp yanmars

[cat man do]

Originally Posted by fastcat435

Somebody with a Snowgoose needs to get his log ( or his head ) recalibrated even 8 is almost impossible with 2 x 27 Hp yanmars

I was being generous and didnt want to offend.

Dave

[Eleven]

ThePHNX
Registered User

Profile: Posts: 1

Prout Snowgoose Performance
Excellent postings by several showing their experience. My Prout Snowgoose was the largest of the canoe stern older models she was extremely efficient either under sail or engine. Have always considered those Prouts to be true motor sailers with excellent hulls, absolutely no turbulence in the thin wake.
During sea trials in England, before loading her heavily for comfort and fun (dive gear, compressors, arms and ammo,) we did 11 knots by GPS by sail and 13 by engine (I maintained an inventory of props for best use).
The Prout is heavily dependent on the headsails and a proper airfoil slot between the staysail and main (min-sail).
She did not point well, I admit, but being an aviator and navigator more than a purist sailor had no problem calling on engine (on long crossings I run the engine at night regardless).


I took the trouble to search this time. I admit to a small error but I hope one and all can admit that the old 'goose was a clean machine. OK 18 v 13 is double the power.
If you need more data talk to the man or check out the data and sail areas provided in Multihullworld's supporting blurb for the one they have on sale. Most were fitted with one Yanmar on a sillette drive leg. Prop shafts, to my knowledge, weren't a good idea then. (Either.)
These were built and sold for cruisers, they were ultra safe, they performed quite well. I suspect that cruisers in those days didn't take fridges and a/c with them so were generally lighter that is considered comfortable nowadays.
I take no responsibility for the data provided. And it would make a good trials model.

[cat man do]

Eleven;
Interesting that the old Snowgoose 37 with it's standard 27hp is listed somewhere on these threads as doing 18kn under power.

So 18 is now 13

Originally Posted by Eleven

ThePHNX
Registered User

Profile: Posts: 1

Prout Snowgoose Performance

and 13 by engine (I maintained an inventory of props for best use).
.

any takers on 8 or less?

You'll get more power from a shaft and prop than a sonic/sillete as well (I would suggest)

Dave

[ssullivan]

Originally Posted by Eleven

ThePHNX
Registered User

Profile: Posts: 1

Prout Snowgoose Performance

During sea trials in England, before loading her heavily for comfort and fun (dive gear, compressors, arms and ammo,) we did 11 knots by GPS by sail and 13 by engine (I maintained an inventory of props for best use).
OK 18 v 13 is double the power.

Must have been one heck of a current helping this 'Goose along?

We have many Prout Snowgoose owners on this board. Maybe one could chime in and let us know what they get for average speeds under power in the real world?

[fastcat435]

Originally Posted by ssullivan

Must have been one heck of a current helping this 'Goose along?

We have many Prout Snowgoose owners on this board. Maybe one could chime in and let us know what they get for average speeds under power in the real world?

I have sailed the Snowgoose Elite 37 ft and under sail I got a maximum of 11 knots and under power no more than 8 but that was still good for a 37 ft heavy build cat in those days

[nevetsyad]

Originally Posted by GreatKetch

Brett,

uuuummm....

You're joking right? That's not a solar powered boat. It is a boat that has solar power cells tacked on.

Did I really need to say "powering a boat only with solar power isn't even theoretically possible for the foreseeable future."

HopYacht 30. All solar/wind powered. No, you can't motor for 150 miles a day for a week, but it's not meant for that, it's a sailboat. It can motor about 10 hours at 5 knots, before it needs to charge for a few days off solar. But again, if you're motoring all day, maybe just get a trawler?

Slow down of course, it goes much farther. Sail and kick in a knot or two of motor constantly if you wanted to and had good sun. And yes, you can stack in more batteries if you wanted to motor longer, but solar is maxed out, gets about 10-15 miles back from sun a day.

[SailingHarmonie]

Originally Posted by nevetsyad

HopYacht 30. All solar/wind powered. No, you can't motor for 150 miles a day for a week, but it's not meant for that, it's a sailboat. It can motor about 10 hours at 5 knots, before it needs to charge for a few days off solar. But again, if you're motoring all day, maybe just get a trawler?

Slow down of course, it goes much farther. Sail and kick in a knot or two of motor constantly if you wanted to and had good sun. And yes, you can stack in more batteries if you wanted to motor longer, but solar is maxed out, gets about 10-15 miles back from sun a day.

Honestly with those kinds of limitations, I have to ask, why have an engine at all? I mean it is a sailboat, right?

The cost of a full electric install is quite large. The time needed to recover fuel costs is basically infinite if you use an engine that little. It's a huge expense that seems to be more virtue signaling than a practical and economically rational installation.

It seems to me it is useful for getting into a marina in calm conditions. There are WAY cheaper ways of doing that. But if it makes you feel better...

[nevetsyad]

Originally Posted by SailingHarmonie

Honestly with those kinds of limitations, I have to ask, why have an engine at all? I mean it is a sailboat, right?

The cost of a full electric install is quite large. The time needed to recover fuel costs is basically infinite if you use an engine that little. It's a huge expense that seems to be more virtue signaling than a practical and economically rational installation.

It seems to me it is useful for getting into a marina in calm conditions. There are WAY cheaper ways of doing that. But if it makes you feel better...

Get into a marina in calm conditions? It can do hull speed if needed. Just not for 10 hours.

Why have an engine at all? In case you need to get into an inlet before a storm? If you want to hop between islands when there’s no wind? A day of motoring isn’t enough for you? As you said, it’s a sailboat. Buy a trawler and motor all week if that’s what you want.

Creating your own “fuel” anywhere on earth is amazing. Winterizing the engines? Fuel or engine maintenance? Things of the past. Need some instant torque to avoid drifting into something, no need to leave the stink pots running so they’re warmed up, just bump the throttle forward when needed.

They just increased the entire catamaran to 300K from 225k, demand was too high at the lower price. Conversion costs are coming down, capabilities are going up. Remember when you’d be lucky to get in and out of a marina on electric alone? That was just maybe ten years ago.

Now you can buy an electric, solar powered, island hopping catamaran for as much as a similar gas one.

[CatAdventure]

Originally Posted by KHK007

Hi everybody,

Just to make clear:

I'm probably a little bit ahead of technology.

Yes, it's supposed to a kind of stunt and I'm aware that I'll not beat any circumnavigation sailing record done under sails. I'll alos stay in area where there is a lot of sunshine. So, I'm not going around Cape Horn.

If there is no sun, I'll have to wait for it if running out of battery energy. That's a little bit like an (ocean) saling race where the guys are not allowed to use their engine: What do they do if there is no wind? They wait for it...

It will not be possible to make sails of silicon solar cells because they might break and can not be folded. Maybe there will be more flexible organic or other solar cells one time, but not at the moment. And the solar cell in sails would not be well exposed towards the sun around noon when there is the maximum energy available...

Anyway, I know now it's possible as a stunt, I just need to be patient as I will depend on weather like sailors and figure out which is the best cat and the best propulsion system...

Greetings from Paris,

Kai

Following this very close.
I have the idea/plan/dream of getting a fully electric cat (44 to 50 foot) to cruise around Australia and beyond.
I truly believe that batteries got to a good point these days, a good bank of LFP are safely enough and have good energy density. The main "problem" now are the solar panels, but I can see how they are evolving every month, I hope they get much better for when I build by setup; but even now this is very plausible.
My numbers at the moment are 2 x banks of 20kWh, with 2 x 15kW Oceanvolt (for regeneration and feathering props) and at least 5kW of solar.
This setup should be good for motoring 5 to 8 hrs with each motor, then if you get no wind, usually it's a lot of sun (on the tropics); and the worst case scenario you wait for the wind.
I have seen a lot of electric cats but I'm still looking for someone that can show me how much power they use at 4 or 6 knots to see how long you can run from your solar panels using say 2000W, for example.
What I can see is the amount of maintenance required on the engines, then the problems in some places to get good quality diesel and the time people expend re fueling and maintaining the whole system. If you put all the numbers together the electric system is not more expensive and is getting cheaper everyday. You really make your boat and your life a lot more efficient.
I know many people make comparisons with the diesel engines and we can discuss this forever; but I believe is worth to make some compromises and change the mentality. You can also get a small genset for safety as well, redundancy is always good.
Just my thoughts at the moment.