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robalex117

Member Since 03 Jan 2007
Offline Last Active Yesterday, 04:22 PM
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Posts I've Made

In Topic: Boots

21 February 2017 - 11:19 PM

Zhik Seaboot.  Don't cost as much as Musto or Dubarry.  Only negative is they are warmer than other boots I have had.  Good thing when it is cold out bad thing when it is marginal sea boot weather.

 

Pluses outweigh negative for me and I would buy them again.

 

Rob


In Topic: Steve and Dave Clarks Unidentified Foiling Object

15 February 2017 - 07:49 PM

I am sure we could.  Just need about five boats.  

The Larchmont one will also spend all of August on Shelter Island for anyone who is on the East End.  Maybe we can get a UFO division together at the HPDO at American YC in October and not have to race Portsmouth Yardstick under a random number that won't have been properly established yet in all likelihood.  


In Topic: 'The Tesla's of the sea are not far off'

15 February 2017 - 07:01 PM

I made that point about recharging under solar.  Maybe a small 1kwh bank, but to recharge a large battery pack, lets say 20kwh solar won't do it unless you let the boat set for a month.  (Just a guess.)

 

Regen is finicky and in our situation we don't bother due to issue after issue but that is the dream and are hoping with my new electric motors that dream will be a reality.  Going 12+knots under sail means a lot of power is available to generate electricity. 

 

 

Another benefit of a diesel electric is the diesels don't need to be that big.  On my 60' cat I have two 21.3kw gensets. (29hp)  When I need lots of power the batteries take the peak.  A comparable boat with straight diesels would have double or more than double that size diesel engine.

 

 

 

Upthread, someone said "forget about recharging batteries via solar, only real way is via regen underway"--- based on my experience, I disagree. I think regen is the most oversold aspect of electric boat propulsion (but, yes, it sure seems sexy in concept). Maybe when you are crossing oceans... But my use scenario (at least until I do that ocean crossing that is on the bucket list) is more pedestrian: I row out to the mooring, load the beer, friends, and dog onto the boat, and then motor for 5 minutes until I'm on the bay. Then I shut down the ICE and go sailing. Rinse and repeat at the end of the day (minus taking the beer off the boat). Worst thing ever for an ICE as I understand it. So... now I use the electric motor for those 5 minutes each way. Do I see regen? Yes, but not much. Every so often, I flip the clutch, run the ICE and bulk charge the 48v bank. But, lead acid batteries don't really get a full charge this way, so, this past season, I added a 40W solar panel, thanks Ham Ferris (coupled to a 12v-48v "boost controller) and I find that it does just fine at topping off the 48v bank. Sometimes, I can even skip running the ICE for the bulk charge if I am occupied with other things and skip a weeks worth of electric motoring out to the bay and just let the solar panel do all the charging.

 

Just my 2 cents, your mileage may vary.


In Topic: 'The Tesla's of the sea are not far off'

15 February 2017 - 06:52 PM

Kent,

That is exactly what we do.  When motoring we only use one genset and turn both props.  Very rarely maybe 5% of the time when we motor and need the extra speed do we run both gensets.  The redundancy is nice but I think if I had to do it all over again I would skip the 2nd genset and get one larger one.  Right now I have two 21.3KW sets.  I think one 35-40kw would be fine.

 

A cat could conceivably have a genset in each hull and run both electric motors off one generator if the other one dies or if you don't need all the power from both diesels. Running one at 60% power is much better than two at 30% power each. 

 

 


In Topic: 'The Tesla's of the sea are not far off'

15 February 2017 - 01:03 AM

Alex it looks like you know your stuff but I think people are confusing diesel electric boats with electric boats.  Diesel electric is  proven and has a lot of benefits.  For small boats, i.e. (not cruise ships) adding a modest battery pack allows for peaking, buffering, and running large hotel loads, (Air con.) without using the genset.  Also allows short motoring, lets say 10 minutes or so, without starting the genset.  

 

An electric boat without a diesel generator will be a nitch boat for a specific purpose.  Maybe somebody who does not go far from home port or somebody like psychosailor who just sails.  (I understand psychosailor does have a very small genset but in general it looks like he/she just sails)

 

But by definition diesel electric will have a diesel engine and I agree with you I also expect to be using a diesel engine in my sailboat.  But also might have an electric motor. 

 

I really hope that electric cars take over completely in cities in the next 20 years, and think it's possible.  I expect that I'll still be using a diesel engine in my sailboat in 20 years though, even though I'd rather use electric.