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Old 07-02-2018, 15:39   #46
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Re: Making a diesel electric trawler for coastal/loop

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I sail in the PNW. We use these things called tide charts and don't try to motor against a 6 knot tide.
ya, started using them around 50 years ago in pnw. you sail in a trawler? limited at 4 knts? ha ha ha, whatever you say hotrod.
and I motorsail all the time against the tide, pretty hard to get anywhere here unless you can and do. so where are you "sailing" on your trawler on? lake union?
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Old 08-02-2018, 08:45   #47
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Re: Making a diesel electric trawler for coastal/loop

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ya, started using them around 50 years ago in pnw. you sail in a trawler? limited at 4 knts? ha ha ha, whatever you say hotrod.
and I motorsail all the time against the tide, pretty hard to get anywhere here unless you can and do. so where are you "sailing" on your trawler on? lake union?
Sailboat, but we have left Friday Harbor in zero wind situations and had to use our 6HP outboard which only pushes us at roughly 5 knots hull speed. By timing the tides we are able to easily make Anacortes by late afternoon.

Sorry but you made it sound like all you need is 250HP and 600 gallons of diesel and you can ignore tides.
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Old 08-02-2018, 09:13   #48
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Re: Making a diesel electric trawler for coastal/loop

With 250HP and 600 gallons of fuel you CAN ignore the tides - provided you have your wits about you. Take note that that is PRECISELY how the commercial traffic negotiates Skookumchuck Narrows in Sechelt Inlet. If you like you can have a go at it in Deception Pass when she's in full spate.

My technique for Deception Pass as well as Dodds Narrows, if I miss the slack, is to go on a fair tide, turning about and stemming it while going full bore ( = 6 1/2 Knts). That sets me BACKWARDS over the ground at several knots. As I said: Keep you wits about you if you try it. Deception is fairly safe. Dodds requires far more vigilance. And don't ever try it in Skookumchuck or Dent Narrows. If you do, the likelihood that you will be sunk is quite high!

We can all do the math of electric propulsion. I see that you've been toying with the thought for a decade or so. I think it'd be wonderful if you could give us a report of actual, real life operational results of any trial runs you may have to report on.

Cheers

TP
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Old 08-02-2018, 09:31   #49
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Re: Making a diesel electric trawler for coastal/loop

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I used an older Torqueedo 1003 on our 17 foot sailboat (about 2500 pounds displacement loaded with 2 of us in it). This is a geared down brushless motor turning a fairly large prop. It had a 300 watt-hr battery.

I could get 2 hours or so of run time doing about 3 to 3.5 knots.

This is why I was saying even a small solar system could beat a sculling oar. My personal experience. Maybe not "any" electric motor/drive, but something like that Torqueedo system.
Actually, on my boat, a torqeedo with 270 watts of solar is a fairly even match to the sculling oar. I tried this, and the torqeedo needed 200 watts to equal what I can do with the sculling oar.

The torqeedo is designed for lighter displacement, actually even smaller than 2500 pound boats. It is going to be more efficient on the 2500lbs than my 8000 pounds. I'm fairly sure I could scull this boat you have at least 3 knots for hours provided I made a custom sculling oar for it.

To get the same efficiency pushing a larger boat you would need a different propeller more reduction gears, and lower rpm.

So yes, a 270 watt solar panel could (in strong sunlight) beat a sculling oar, but not with typical drive systems that most people use, and certainly not by using the existing inboard shaft and propellor with a motor on a belt drive which is common.
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Old 08-02-2018, 09:51   #50
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Re: Making a diesel electric trawler for coastal/loop

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If it was ANYBODY else I’d say you’re crazy.

You though, sound like you could pull this off ;-)
My thoughts to !

KTP, welcome to the land of the all-knowing !
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Old 08-02-2018, 10:40   #51
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Re: Making a diesel electric trawler for coastal/loop

To go back to the first couple posts, Budweiser and Tesla seem to think the electric trucks will work out ok.

I think a catamaran is going to work better. You say a 4’ draft so that must be a 36 or 38’ trawler. That will need more than 2000 watts to make 4 knots. But maybe a 32’ cat could do that speed and more square footage for solar. Likely more living space as well.

You probably do want a backup gen atleast a Honda 3000 so you can get out of emergency situations and maybe a small sailing rig.
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Old 08-02-2018, 14:00   #52
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Re: Making a diesel electric trawler for coastal/loop

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My thoughts to !

KTP, welcome to the land of the all-knowing !
I'm not all knowing and never claimed too, but I do what I do and I know what I know.
The real problem is not what I said or how I said it. The problem would seem to be more of along the line of as you said, "my thought's to" and KTP saying
"well it sounded like" maybe both of you can stop trying to read crap in to post's where none exist. know it all indeed ha ha, but you two both read a **** ton into a simple post, so who thinks they know what?
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Old 08-02-2018, 16:03   #53
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Re: Making a diesel electric trawler for coastal/loop

Well it looks like we are going to be spending all of our funds on a Crealock 34 sailboat so I guess there goes the experiment idea (I will not be chopping off the keel and mast on this baby)

Going to have a lot more room than our Monty 17!
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Old 08-02-2018, 17:18   #54
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Re: Making a diesel electric trawler for coastal/loop

Nice choice. Beautiful boat with a strong reputation.
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Old 09-02-2018, 12:38   #55
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Re: Making a diesel electric trawler for coastal/loop

I think you will be pleased.
A sailboat can be phenomenally efficient on motor, we motored down the ICW from Brunswick Ga to Vero Beach Fl, burned 35 gls of Diesel and that includes 20 hours of generator time.
My fuel burn at 1900 RPM is less than a half a gallon an hour, and I think the generator burns maybe a quart an hour.
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Old 09-02-2018, 19:27   #56
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Re: Making a diesel electric trawler for coastal/loop

Trawlers are awful designs for so many reasons, we should recycle them. You are better off getting a trimaran that can sail efficiently in light wind. Keep it light. Now you will make the great loop much faster without any propellers than you could on a "solar trawler"[/QUOTE]

The trawler label is so overused it's almost meaningless. Most have inefficient semi-displacement hard chined hulls. However, real full displacement "trawlers" are awesome boats & superior to multihulls for exactly the reason that you point out,"Keep it light". That's not an issue for a displacement hull trawler which means you can bring as much stuff as you need & push it around with very little horsepower. When cruising & living aboard that's a great feature.
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Old 11-02-2018, 03:30   #57
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Re: Making a diesel electric trawler for coastal/loop

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Trawlers are awful designs for so many reasons, we should recycle them. You are better off getting a trimaran that can sail efficiently in light wind. Keep it light. Now you will make the great loop much faster without any propellers than you could on a "solar trawler"
The trawler label is so overused it's almost meaningless. Most have inefficient semi-displacement hard chined hulls. However, real full displacement "trawlers" are awesome boats & superior to multihulls for exactly the reason that you point out,"Keep it light". That's not an issue for a displacement hull trawler which means you can bring as much stuff as you need & push it around with very little horsepower. When cruising & living aboard that's a great feature.[/QUOTE]

Partly true. You can load up a trawler with an extra few tons of gear and have almost no impact on efficiency or HP required. The problem is a true displacement trawler hull is like riding a weeble-wobble unless you add stabilizers or a steadying sail which eats into that efficiency.

As with most things, there is no "best" option for all considerations.
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Old 11-02-2018, 04:16   #58
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Re: Making a diesel electric trawler for coastal/loop

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Well it looks like we are going to be spending all of our funds on a Crealock 34 sailboat so I guess there goes the experiment idea (I will not be chopping off the keel and mast on this baby)

Going to have a lot more room than our Monty 17!
Excellent decision! That's a tough, seaworthy vessel which will get you anywhere you want to go.

I presume it's got a nice, direct drive diesel engine for the times you can't sail?
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Old 12-02-2018, 20:46   #59
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Re: Making a diesel electric trawler for coastal/loop

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Partly true. You can load up a trawler with an extra few tons of gear and have almost no impact on efficiency or HP required. The problem is a true displacement trawler hull is like riding a weeble-wobble unless you add stabilizers or a steadying sail which eats into that efficiency.

As with most things, there is no "best" option for all considerations.
Small ones yes big ones not so much of a problem
We have no stabilisers or steadying sails and in two years of full time liveaboard and cruising have only wanted them once for about 20 minutes on a 30 knot beam sea section.
Changed course, added a few miles to the trip, problem sorted.
Being retired and full time on board does mean we can be smart about our movements.
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Old 22-02-2018, 05:23   #60
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Re: Making a diesel electric trawler for coastal/loop

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Small ones yes big ones not so much of a problem
We have no stabilisers or steadying sails and in two years of full time liveaboard and cruising have only wanted them once for about 20 minutes on a 30 knot beam sea section.
Changed course, added a few miles to the trip, problem sorted.
Being retired and full time on board does mean we can be smart about our movements.
DESCO, formerly Diesel Sales Company, of St Aug, FL, used to make some sweet round bottom wooden trawler hulls. They made great offshore shrimp boats. However, in seas over about 6', we would drop the stabilizers, AKA flopper stoppers, AKA "paravanes" (we would laugh at the college kids who called them that). The same hulls were also used as snapper boats. No A frame, mast, outriggers, etc. Well, there was often a mast, with a steadying sail, and without all the iron up top, and the stabilizers, that steadying sail was sorely needed. It would get pretty noisy sometimes, in a big storm swell and light winds, but it always helped. Just not enough. At sea, a very round hull loses efficiency due to the need to moderate the motion for not only the comfort, but also the safety of the crew and equipment. Just about anything you can think of that would ease the motion of a very round hull at sea, will reduce efficiency.

Inland is a different matter, of course. Generally, roll abatement is not an issue in protected waters. So paradoxically, a deep, round TRAWLER trawler would be highly efficient, even deeply laden. For a given power setting, we saw zero difference in the channel of speed between a boat loaded with fuel and ice, (several thousand gallons of diesel, up to 200 bars of ice) and nearly empty. Or coming in with 200 boxes (a box is about 104 lbs of shrimp) or getting skunked and coming in with 40. So while a minimalist would do better in a purpose designed solar cat or tri, someone desiring the comforts of home and plenty of water and fuel for the backup diesel, would do well with a very round hull, especially on protected waters.

Unfortunately, "trawler" yachts are seldom shaped like actual trawlers. A few will approach the shape of steel trawlers, that have a good bit of chine. A Kady, for instance. Take the typical 70's or '80s fiberglass sailboat, without the keel, and you are looking at something not entirely alien to the round trawler hull. Such a boat would be punishing, even dangerous, at sea, though.

Everything about boats is either specialized for a specific set of conditions, or a Solomon-esque exercise in compromise.

For an electric looper not equipped with sails, 35 feet or longer, I would want more than 10kw of power at my disposal. Twice that might be acceptable. Can do that with an electric car motor, or two BLDC motors belt driving the same shaft, or twin screws. I would want at least a 40kwhr bank. I would want a 20kw generator and maybe a small one, around 4kw for when the big one is overkill. I would want an absolute minimum of 2kw of solar panels. Twice as much would be nice but crowding that much solar topside would be an issue. Forget about wind generators. The system would not even notice the tiny contribution of a wind generator. It was shown to me on paper by a very knowledgeable engineer that to even have 1kw of generating capacity in moderate winds would require about a rotor with 10' swept area. Doesn't sound very convenient or even safe, to me.

On the loop the big generator would be running, a LOT. Solar would only contribute, at realistic speeds, but would more than make up for the lower efficiency of diesel/electric fuel consumption, so net gain. Ideal conditions and low speed, of course the generator would not be needed. Looping in a year or less at 3kt isn't really a thing, if you ask me. Haven't crunched the numbers but errrr.... I would think that cruising at around 6kt would be a lot more practical. With affordable technology you won't do that with solar alone. Of course nightly pit stops for shore charging would help, but there goes your schedule. Taking two seasons to loop, or even three, would maybe make 3kt doable, at risk of much irritation to the smokepot drivers doing 12kt+.

Electrosailing is a thing, yeah, but do you want sails, or solar? Both at once is one of those compromise thingies again, with all the shading of the panels. Nightly shore charging pit stops to the rescue. Sailing is more of an option with very small and maneuverable boats, and you would still want to avoid tacking marathons. Talking about the inland legs, of course. At sea, outside, the sailboat is in its element. Lowering the mast doesn't have to be a major project, with a tabernacle step. Everything can be rigged so that no shoreside help is needed, crew could raise and lower quite nicely at anchor.

In reading my comments, do keep in mind that I have never done the loop. I do have an electric boat, though, and I am aware of the limitations imposed by the technology and some of the things that can be done to circumvent them.
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