CS17 Hull 129 Progress Report

[Tom Williams]

Hi guys. It's been a while since I posted any pics of CS17 hull 129 so here goes. I've had to focus my attention on some other projects recently. The biggest was a "Lean to" on my barn to house the boat when it come out of the shop. It's almost done ! I've pretty much given up getting the boat wet this year and have set my sights on getting it onto the trailer and into the barn before it gets snowed in (early Dec.). My wife has orders for some furniture projects this winter so I'd like (need) to clear the shop.

The biggest items left to build are the masts. Other than that is lots of little items like oar locks, deck hardware, hatch tie downs, varnish, ... ( :shock: maybe early Dec is optimistic!!)

Tom

[bkeats]

The electric motor is very unobtrusive. Does the battery take up a lot of space? What do you expect the range to be like?

Brian

[Ray Frechette Jr]

Range is the buggaboo with electric propulsion.

Range will depend on how bog a battery bank you want.

As a  general rule you don't want to deplete a battery more than 50% if you want a reasonable life from it.

Standard 100Amp hr battery than will give you about 50 amp hrs to play with assuming you had it topped up before leaving.

And proper seamanship would call for you to leave at least a third of capacity at bay for unforeseen.  So figure on roughly 35 amp hr for propulsion,  or if you like to live on the edge go with 50 and figure you will sacrifice battery life for unforseens.

Figure a CS 17 will likely consume 20 amps to push at 3 MPH boat speed.

So a single 100 amp hr battery should get you roughly 5-6 miles before it gets seriously low.

Not bad in a lake.  In the Ocean though if you have any sort of tidal current...  I can easily see currents of a knt to a knt and a half here in Maine.

That range drops off right quick in such =conditions when 3 mph thorough the water gets you a little less than a mile and a half over ground. 

But then again I never have any motor on My CS 20.  I have lots of sail area,  a set of 9 foot sweeps and a good anchor to hold position when all else fails  and a good deal of seamanship sense to plan the day according to the currents I will face.

Man sailed around the world before the infernal combustion device was foisted upon us.  It can still be done now too.

[Peter HK]

Figure a CS 17 will likely consume 20 amps to push at 3 MPH boat speed.

So a single 100 amp hr battery should get you roughly 5-6 miles before it gets seriously low.

Not bad in a lake.

I agree with you in general and range is a problem, but the issue with battery life and cycling is often not considered clearly.

I occasionally go lake sailing where fuel powered engines are banned. With respect to range/amp draw/speed I recently did some actual tests with ammeter and gps with my 30 pound thrust electric motor.

Amp draw going up the 5 speeds was 7/9/13/15/28 and speed in knots was 1.6/1.8/2.3/2.5/3.3. Range (assuming 33 amp hours) varied from 7.4 miles down to 4 which is enough for me.

So how big a battery? Shelf life unused for an AGM battery is about 5 years. I go to the lake 3-4 times a year. So all I need is 20 cycles (4 by 5). From the Lifeline batteries technical manual 50% discharge allows a thousand cycles and complete 100% discharge allows about 400 cycles. This would allow 80 trips to the lake a year at full discharge and last 5 years- the shelf life of the battery. I'm happy to have a smaller battery and fully discharge it for the number of times I use it.

[Randy Jones]

I agree with you both.  I went through a similar thought process a few years ago and it lead me to look for a small and very quiet gas powered DC generator that could be installed on board and used to recharge batteries.  The basic idea being to use a two battery bank with the ability to recharge as needed - a small "gas electric" if you will.  I found that typical generators provide most of their output as AC power and only a small DC supply. Conversion (rectification) of AC to DC could be done, but doing it at high amperage gets expensive fast and doing it at low amperage means longer generator run times.

My ultimate conclusion was that a small and quiet DC generator is technically possible but not on market.  For now I just row when I have to.       

[Peter HK]

Randy said

For now I just row when I have to.     

The reason I bother with any motor relates to the only time I was becalmed on this lake when there was promise of breeze and we'd sailed perhaps 6-7 miles when it died. This was on my Bolger 31ft folding schooner

[Ray Frechette Jr]

. From the Lifeline batteries technical manual 50% discharge allows a thousand cycles and complete 100% discharge allows about 400 cycles.

Of course that too needs some further development.

I t assumes drawing the battery down at the c20 rate to level of discharge specified and then recharging it back as soona sit gets down to that level.

IE on a 100 amp hr battery the c 20 rate is 5 amps.  Discharging at 5amps per hour for 20 hours and then immediately recharging is a different wear curve that drawing 20 amps for 5 hrs and then recharging the next day after you get home if you remebered to.

Higher discharge rates yield increased heat.

And longer periods of being discharged mean more sulfation of the plates.

And AGMS and gellc ells do not like equalization charges applied to them much.

Batteries are very heavy leaky expensive fuel tanks that don't have a whole lot of capacity and consumes energy just to fill them back up.  And they don't last very long either.

Other than that they are great!

If anyone might be interested I am giving an Intro to Marine Electrical course at Wooden Boat this summer.

[Peter HK]

Batteries are very heavy leaky expensive fuel tanks that don't have a whole lot of capacity and consumes energy just to fill them back up.  And they don't last very long either.

Other than that they are great!

No one can disagree with that, but I add one further attribute...dangerous.

I've had one battery explosion, only very mild, from hydrogen produced by charging, in a well ventilated compartment. There was a loose electrical  connection at one terminal which sparked and the local concentration of hydrogen was enough to ignite. The higher concentration of hydrogen within the wet cell battery above the electrolyte blew the lid off. Luckily the electrolyte was contained and we could pick it up and dispose of it. Very little was sprayed around.

I'm very careful with these things.

Cheers

Peter HK