alternate auxiliary propulsion

[curtisv]

This quote is from another thread.

   An aside- do you use premium fuel in your outboard?
Bob23

No problem with fuel in my trolling motor.  :-)

OTOH - Lots of problems with spade lugs breaking inside the motor controller housing.

Anyone else using a trolling motor on a CP23 (or larger)?

Has anyone built and used a sculling oar?  I've been meaning to for quite some time but haven't got around to it.  I suspect that I may have to build more than one before getting it right.

Curtis

[Bob23]

In a recent "Good Old Boat" issue, there was an aritcle about using a really long sweep deployed on one side of his Nimble 20 and using the rudder for direction control. The skipper reported  being able to maintain speeds of 1 knot which might be helpful in a lake but here in NJ, our tidal speed often exceeds that. Still, I'd love to build one just to try it out. That being said, I love my Nissan 8!
Bob23

[Craig Weis]

The Star Boat dad sailed had no motor or sculling, simply a canoe paddle rarely needed when maneuvering within Belmont Harbor.
I don't like electric motors on boats, unless they are model R/C boats.

skip.

[brackish]

No, but if and when my 9.9 ends its life cycle, I would consider, if the technology is there, an electric inboard.  The thought of silent running with the ability to better distribute the weight of battery banks and motor is intriguing.

[Craig Weis]

Ever here of a submarine? A 300 foot long pig boat or fleet boat of WWII era can float or sink with just a tiny smidget of its total weight in the form of a few tons of sea water. It's entire length if cut cut vertically from keel to about 9'0" high vertical, with the exception of the bow and stern sections, is all battery. That's a lot of weight.

Entropy guarantees that putting juice 'in' is much slower then pulling 'the juice 'out' of any chemical reaction occurring within a battery pac. And I just can't trust that the power will be there when the skipper calls for 'Get her up to ramming speed'.

I'm guessing that when the 9.9 gives up the ghost you'll buy another 9.9. Unless you want to sail around in a solar panel. "equal HP inboard with fuel tank and have reasonable range". Sorry don't see that happening.

skip.

[Bob23]

Battery technology will have to get way more advanced before I consider electric. Gas is easy to store on the foredeck and gives a longer range, pound for pound as oppposed to batteries. Consider a future voyage for me will be through the Chesapeake and Delaware canal, where sailing is prohibited so a 19 mile motor-voyage is manadatory. An electric outboard would not make it. But I do like the idea of silent, clean propulsion.
Bob23

[brackish]

Did you guys miss the part that said if the technology is there?

95 percent of the time, my motor is used to get out of and into the marina, (where I plug the boat back into shore power) or to approach an anchorage.  That may be the case with most sailboats.  If the total weight could approach that of an equal HP inboard with fuel tank and have reasonable range, I would consider it.   

As an example of what could be, Torqeedo makes electric outboards that are thrust rated at 9.9 hp, propulsive power rated at 8 hp (gas outboard comparable) with 24 volt batteries that, interpolated from their data, at half throttle for a Compac 23, should provide about 20 nm on a charge.  The motor and two batteries weigh 124 lbs.  That is less than my 9.9 with a full gas tank.

Maybe not for long distance cruising and expensive at this time, however, intriguing what could be in the not so distant future.  I wouldn't want an outboard, that would defeat the purpose of weight distribution, but an inboard would be nice.

[Bob23]

   Ahem...I did miss that part. I didn't realize the Torqeedo's could go that far.
   When we bought our first Makita cordless drills many years ago, we thought it was the best thing since mini-skirts. Remember, I'm and older-school carpenter. Framing square, handsaw, yankee screwdriver ( I have 2), and pre- power mitre saw.
   Makita (and all the other brands) have gone through many evolutions to where they are today-18V Lithium Ion...they last many times more than the original NiCad.
   So, yes- it is amazing to wonder where this technology will be in 5 years. Maybe plutonium pellet powered outboards and mitre saws. Maybe our cars will be powered by Mr. Fusion- see "Back to the Future", one of my favorite movies!
Bob23

[curtisv]

My original question is does anyone else use a trolling motor on a CP23 or sculling oar?

Regarding electric propulsion, the technology is there or getting there for what I want to be able to do.  Launch and retrieve once a season and get out of the way of any powerboater that might be getting a bit annoyed because a sailboat take a little longer at the ramp than a power vessel.  Occasionally move out of the channel or a few miles in force zero conditions, again only a few times a season where I sail.  I'm willing to ghost along under sail in force zero plus epsilon conditions.

I looked at this years ago and what was available then was 0.5-8 HP electric motors for inboard and lead acid batteries.  Later some electric outboards came and most went.  Same batteries.  Torquedo is very expensive because it uses an advanced battery, lithium ion.  Toyota isn't even using lithium ion yet in the Prius.  The battery technology is great but still expensive.  Like LED that was insanely expensive just a few years ago, give it a little time.

In the mean time, two group 27 or group 31, or one 4D or 8D holds a lot of energy.  They weigh 120-160 pounds but you can put that weigth on the center line and closer to the fore and aft center.  I took a 90+ pound off the stern in the same season I added a 160 pound 8D batter where the CP23 diesel would otherwise go in a CP23D (that weighs 300 pound I think).  My trim improved a lot.  No more bow up and wanting to move as far forward as possible in the cockpit to get the best trim.

For what I want, the trolling motor would work just fine if it would just work longer than 15 minutes a season.  Of course after launching and having it die I could fix it before the next season, but that tells you how much I don't miss having it.  For three years now I've retrieved entirely under sail.  Anyway that's a story of my laziness in getting a thorough fix for the problem instead of replacing the original spade lugs one each season.

The sculling oar "technology" could be called "mature" at this point and from my experience with the somewhat modified trolling motor seems more reliable.  The Pardeys claim to get close to 3 knots under Lin power (Lin is a short light woman) and over 3 knots with Larry power.  That is on a 30 foot 20,000 pound wooden blue water vessel.

There is real good info on building a sculling oar at http://www.shawandtenney.com/wooden-rowing-oars.htm and http://knockaboutsloops.blogspot.com/2008/08/how-to-build-sculling-oar-by-jerome.html.

Some how to at http://www.scullingoar.bravehost.com/ and http://www.woodenboat.net.nz/Stories/Sculling/scullthree.html.

An engineless sailing blog is at http://knockaboutsloops.blogspot.com/search/label/Engineless%20Sailing.  (highly opinionated).

There is a long thread on this topic at wooden boats http://www.woodenboat.com/forum/showthread.php?t=107357.  (very very long)

And then on sailfar http://sailfar.net/forum/index.php?topic=1647.0.

I'm glad I didn't spend the large amount of money or weigh down my boat years ago by adding a bit bank of lead acid batteries and an inboard electric.  I looked into it.  It was expensive.  I wasn't sure it made sense.  I'm glad I didn't do it, but not for the reasons most might think.

I found that I didn't need anywhere near the auxilliary range that people insisted I would need that would have pushed me to lots of battery weight and expense.  I was also fixated on the idea of using the prop as a source of charging capacity.  That's not a dumb idea, but there are no reasonable priced products that do that.  Then there is the ever leaky hole in the hull that is needed for the prop shaft.

So I concluded that inboard electric was overkill on a CP23.  After my first two seasons with a CP23 I found I didn't really use the outboard.  I used it the first season sometimes because my wife was impatient and sometimes because the 150 genoa and no way to hold down the boom (no vang or traveller) makes the stock CP23 setup "much less than ideal" for strong conditions.  Second season my wife was getting the hang of this not hurrying sailing thing and I had a vang and had the genoa cut smaller.  Third season we used the outboard even less so I think it was after that or maybe one more season that I sold the outboard and bought a trolling motor and larger battery (my original battery was already shot).  My experience with the trolling motor has been less than stellar but the few times I've used it and it died I just put up the sails and all was fine.

On the topic of convenience and safety.  There are places that I sail that I have to wait no matter what.  You can't get a CP23 through one foot of water with or without an outboard so you have to wait for the tide.  You don't want to motor against the tide in Polluck Rip because a fouled spark plug or gunked carburator jet could cost your life (people have died there, some fairly recently).  OTOH - there are times when I've tried to sail against a 4 knot tidal current (where it was safe to do so) and the wind faded and I had to turn around.

On another topic, the safety thing keep coming up but safety statistics don't support the notion that having a motor actually results in improved safety.  In http://www.uscgboating.org/assets/1/Publications/Boating_Statistics_2008.pdf (2008 CG statistics):

In 2008, the Coast Guard counted 4789 accidents that involved 709 deaths,
3331 injuries and approximately $54 million dollars of damage to property as a result
of recreational boating accidents.

The sixth highest rank of accident causes in 2008 (ranking higher than alcohol use, which is way down from #1 less than 10 years ago, #1 is now careless/wreckless operation) was:

Machinery Failure accidents=292 deaths=24 injuries=117

Sail dismasting is listed:

Sail Dismasting accidents=4 deaths=0 injuries=2

The accidents, deaths, and injuries due to engine failure outnumber the totals for sailing.  There were 16 deaths listed as "propulsion method: sail" but 34 deaths for all tyes of sailing vessels (sail only, aux sail, and unknown sail).  Of sailing vessels a bit more than half of the deaths, and way more than half of the accidents were of sailing vessels operating under power.

Anyway, the point of that was that more sailing vessels get into trouble under power and more deaths occur on sailing vessels under power than under sail.  Coast guard does not break out sailing statistics very well in the reports so for example, it is not possible to know how many of the sailing vessel deaths operating under power were due to engine failure.

In one of the Pardey books Larry argues that the reason is that sailing vessels with power take down the sails and put the boat in a position where an engine failure will cause an accident, possible loss of the boat, and possible death.  Others have made this argument as well.  A line wound on the prop, a plastic bad in the cooling intake, bad fuel or a shaken fuel tank from the sail, and the engine dies.  Unlike engineless sailors who plan a strategy if the wind dies, be it having an anchor ready or an oar, those with engines too often have too much faith in their propulsion.

Back to the original question.  This season I might get around to building a sculling oar so I was wondering if anyone had done this for a CP, and specifically for a CP23.  If so, I might be able to learn from the prior experience about dimensions and construction.

Thanks,

Curtis

[Shawn]

For a sculling oar setup check out:

http://www.duckworksbbs.com/gear/scullmatix/index.htm

Shawn

[kickingbug1]

   in regards to a cp16, i think they can be rowed. after doing some measuring i think 7'6" oars would work but they would have to be two piece so they could be stowed below. every once in a while i consider oars but my 30 year old outboard still runs fine. maybe when i submit to "green" pressure.

[Salty19]

In a fleeting fantasy, I would love to have a strong electric outboard! Like curtis, I really only need the motor for short periods and for short distances. Either at the docks for manuevering or for smooth beach landings (and the occasional assistance with tacking). Rare times to beat the storm back to the dock.

Realistically I probably won't take any steps towards this goal, but have thought about it.  I even put some elements on paper once. 

Maybe a custom high-torque motor install with custom prop/shaft.  Mount the motor under the cockpit floor with a shaft going to the prop via a stuffing box. Fabrication of parts and some engineering know-ho would be needed of course.   

It's been done before.

[Shawn]

"As an example of what could be, Torqeedo makes electric outboards that are thrust rated at 9.9 hp, propulsive power rated at 8 hp (gas outboard comparable) with 24 volt batteries that, interpolated from their data, at half throttle for a Compac 23, should provide about 20 nm on a charge."

Isn't that the Cruise 4 that is rated to that power level? That is a 48v system.

Where did you find that weight? They recommend 200 amp/hour batteries. A single 4d battery in that size is about 135 pounds and costs $500, and you need four of them for 48v.

Torqeedo rates the shaft power on the Cruise 4 as about 4.7 hp. If you are running at half power (2.35 hp) a single HP is 746 watts. So for 2.35hp that is 1753 watts of power, but Torqeedo also says their engine is roughly 50% efficient. So you are really looking at 3506 watts of power. 3506 divided by 48v is 73 amps. So basically for an hour of use you would use about 73 amp hours from your battery bank.

How are you going to recharge that loss?

Shawn

[curtisv]

For a sculling oar setup check out:

http://www.duckworksbbs.com/gear/scullmatix/index.htm

Shawn

Thanks.  The offset coupling is an interesting idea but at $50 for a coupling, I'll twist the oar by hand.  They do have some nice oarloacks.

If you know of a coupling that I could buy that is reasonably priced and would allow me to make a three peice oar that would be great.  I'm planning on about 2 inch diameter on the shaft.

Curtis

[Craig Weis]

So 3412 btu's per kw.
or 9.9hp = 13.2589 kw x 3412 btu = 45,240 btu's for 9.9 hp motor. The btu's are always in hours.

Replacing JUST a single 1-HP motor with an electric motor, eliminates one barrel of oil, or 520 pounds of coal from being burned. Look at the example below and then imagine how much pollution can be eliminated if all motors were NEMA premium efficiency. {BUT WHAT CAN YOU DO WITH ONE GAS POWERED hp engine?}

Think about this. From hundreds of miles away, three wires about the dia of the thumb [3 phase] brings into a any manufacturing plant enough power to run hundreds of electric motors, lights, fans, heating and cooling units, chillers, welders, conveyors, a scad of computers, battery chargers, golf carts, coffee pots, clocks, and much more.

Just three little wires with electrons running up and down the outside dia of their length 50 or 60 times a second [hertz] from a clean burning coal fired electric generating plant. That can't be matched with wind generating turbines, or solar panels, or wave action. Remember, co2 into plants, o out. Where does the c stay? In the plant...who needs cap and trade? Plant a forest equal to the c footprint anywhere on the globe. Call it good.

skip.


DIY Electric Outboard Motor
This is a battery powered motor for a small rowing boat. The motor used is from an electric wheelchair which ran from 24V. The motor has a built in reduction gearbox to provide a large torque to the wheels on the wheelchair. This gearing ratio was far to high for the propeller. The prop needs to turn much faster in order to generate the right amount of thrust to move the boat.

Fortunately the motor used had a small part of the main rotor protruding from the opposite end to the gearbox which was sufficient to attach a sprocket. This sprocket was linked with a chain to another sprocket on the main axle. This axle was then connected to a 90 degree 2:1 gearbox from a cheap angle grinder which was then attached to the propeller.