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Mathew Flinders 246


Jknight611

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It does,  I may put a doubler,  but it is well protected  (Aft of the stub keel) and not terribly heavy.  It seems a lot of the newer European boats have adopted this pod system and I will R&D some of their installations.   The hull is 18 mm thick where the pod mounts.  

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I did compare the cost of a Beta Marine diesel and the cost is near enough to the same by the time you add up the cost of tankage, shafting and wiring etc.. It is like comparing apples and oranges. There is a lot more energy stored in a tank of diesel than a charged battery, which means that you cannot run at full speed for say 24 hours. You can run for long periods at low speed with sail assist and almost no sound or smell. The Torquedo will regenerate at sailing speeds above 4 knots. The larger battery capacity will allow for more pleasant living aboard running a refrigerator laptops and cell phones etc.. The boat will carry a small Honda 2kw generator for the times when the sun is not shining or you have to run the Torquedo  long and hard.

 

The boat will have more space and no diesel smell. I suspect that the running costs will also be awash if you consider replacing the battery in 8-10 years compared to diesel maintenance and fuel.

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We are building the boat to use offshore,  when we use our diesel powered boat (with solar) we would go 8-10 days not starting the engine.  The electric option is probably 300-350 lbs lighter, maybe more, and if in time we find we need mo juice, another battery would not be out of the question.  We will still be way ahead on weight/space savings.  This is my first experience with electric propulsion so, the idea of no vibration, noise, smell and minimal maintenance excites me.  I spent more than a few hours head down, butt up maintaining Mr Yanmar.  There is plenty of room on Mathew Flinders design for a diesel if that was the builder’s choice.  

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I wish you good success with that electric engine. It sounds very well thought by you.
Yes reading in other Forum the problems that peoples have with their Diesel and their throughulls…?

 A friend of mine has an electric Torqueedo outbord on his smaller boot. For emergency he has a small 2,5 HP gasoline outbord on board.
But he has only used it twice in 5 Years as he has to motor a longer distance on river Elbe. With more spare batteries for his small torqueedo he would not have to use it.

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Thanks,  that is a beautiful boat!  I will spend some time tonight looking!    
 

 The Torqeedo idea started as a passing idea, but I have really bought into it!  I am excited to see how it works day to day.  On initial inspection it looks like a quality piece.  I like the integrated concept they have, and bone easy to install, except for the retraction mechanisms!  I opted for the feathering prop understanding it is required for regeneration, which is a part of my energy budget.  Solar and Honda 2000 will complete the requirements.  

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  • 5 weeks later...

In your cost calculations, you need to factor in battery life.  And with AGM batteries, which I prefer over lead-acid, there are limits to how deeply they can be discharged.  If you go beyond those limits, the battery will not recover. I still like the idea of electric over diesel or gasoline.  But there are no simple solutions for those windless days.

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Hi Don, for the batteries I am using Torqeedo’s new 24-3500 battery,  it is a LI-N-MC battery with quite sophisticated BMS system,  they “advertised “  800 cycles to 100% DOD with 25% loss of capacity.  I will very unlikely discharge to the BMS shuts the battery off.  They weigh about 1/2 of AMG and 3500 watts @ 24VDC.  Quite a lot of power, slightly larger than 2 27 series AMG.  I did get a surprise,  I was understanding that the BMS had an internal shunt that measured the total in/out and displayed it, not so.......so the house loads, though minimal @ 12vdc will go basically unmeasured.......I think.  If that is the case, well still a lot of variables!   Goal is to be able to motor 8 hours at 3 kts, unaided by sailing or solar. 

We initially discussed using several Tesla battery modules but I have/had concerns on a home brewed  system when there are so many other concerns to deal with, so the ultra injuneerin of the Torqeedo looks to be the most conservative approach.  

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An issue to be mindful of when designing a lithium battery system is fire.  A friend of mine nearly lost his boat to fire due to a failure in one of the lithium cells. This was despite having a battery monitoring system that had been carefully designed to deal with this possibility.  Sticking with Torqeedo’s engineered BMS solution is probably a good idea

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  • 2 months later...

Looks like a few months since a update on the Flinders project , true to form, some photos are sideways..... but the hull is inverted in real life.  Electrical system, plumbing, interior are mostly complete, hull is glassed and 82% filled, this 17 oz glass was invented by the epoxy association.  It guzzles the stuff!  The stub keel is my current project,  it is incredibly strong by design, with lots of glass.  I will be taping it to the bottom panels with several layers of 24 oz unidirectional glass, then a overlay of 17 oz biaxial.  That should hold it! 

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Interior looks very nice. Is that the pecan trim? 

 

I am very impressed with what looks like the ease with which you were able to turn the boat. She must be pretty substantial at this point.

Did Graham give you a rotational axis so you would know where to establish your pivot points? Could you post a close up of what exactly the boat is pivoting on?

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The trim is cypress,  long story but I met a young man that was selling pecan lumber, it was beautiful.  I bought some (But not enough) noticed a lump on his ankle under jeans.  He has since become a guest of the state for a 3-5 years.  I did get enough to trim the head area and galley area, it looks pretty nice.  
Alan calculated the CG of the hull and I just put 2 1/2 eyebolts where he said.  He got it perfectly!  The forward end was supported by a engine hoist and the aft by a big cable hoist (cable come-a-long), which was supported by a Harbor Freight scaffolds. 2 hours setting up, 22 seconds to roll.  We build 2 ultra sawhorses that keep the tabernacles 1 inch above the floor.  If I would have thought a little harder I would have waited to install the tabernacles and the bumpkin till it is upright.  I might call it boomkin when it is launched.  

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