Did a dream got shattered?

Hi Tugboat,

Nice to see you are active again. Yes, I agree with you and others. But what I have to find out, is the ventilation requirement, if Lead Acid batteries, even Sealed ones are used. Sealed lead Acid batteries still have a vent and the local authorities may insist on room ventilation and that will be difficult with having the batteries below the waterline .
Bear in mind it is 25 KWh !!
How far are you with your project?

Tugboat, you must be so pleased not to have your tugboat reduced by 10%. The work I have been putting into reading and calculating the stability calcs and righting arms, I could have build another off the shelve plan boat already. But I must say, I have learned a lot.

Bert

 

I believe forced air ventilation is the way to go when charging and may be necessary when running at higher discharge levels too.

-Tom

 

Thanks Tom, I assume I do not need venitaltion when I use LiFePO4 battery packs. This would be another advantage for me to use LiFePO4. If I can get my richting arms right.
Bert

 

This is a question for the yacht builders and NA's.

Look I want to be honest, anybody who is ever planning to reduce a boatplan by a percentage over the 5% is a lunatic. But I have gone that far, and may as well learn and finish the job.

I am busy in calculation the Richting arms for the reduced by 13% Hartley 28 boatplan and I miss station 2, 4 and 8. There are not on the drawing from the designer. Would it matter very much if I calculate with the No 1, 3,5,6,7 and 9 stations only. Either ignore 2,4,8 stations or take a good guess what those 3 missing stations would be.
Thanks for any input
Bert

 

I have re-created the missing stations and have come up with a system to
do it slightly different and easier for me. I used Bostik Prestik with a long piece of paper and all the stations. Much easier for me. No need for help anymore
Bert

 

Those who are already in the new year, Happy new year. Those who have to wait a little longer due to the earth not being flat, have a lovely new year's eve.

The Forum website does not allow me to post the excel files. Most likely the Website does not allow my cookie. However the same Gallery website allows my cookies and therefore I will post the converted excel files in Jpeg files on my BertKu section. But I have to convert them first into Jpeg files.

To get there: Click on Search, Click on BertKu, Click on images.

My question: How stable is the boat I have created and what should I improve.
Should the boat be acceptable, I will then give my conclusion after I have finished and tested the experimental motor and prop system on an exsisting boat of a similar size.

I need to know what the minimum power is needed at our kind of "blue sea" condition. If I am satisfied, I will go ahead, depending on your comment on all my stability calculations.

There are some small discrapancies.
This is due to
a) paper shrinks when dry and hot
b) could not always use the simpson rule, this is due to the hull form and the number of drawings with stations available to me.
c) I made an mm,cm,dm,meter error and the wetted area is not 99m2 but 9.9 m2 for this 6,5 meter LWL boat

But the boat has to be stable with at least a small tolerance allowed. Please be gentle on me, I may have made mistakes.

many thanks in advance
Bert

 

No, “A dream did not get shattered”, but boy oh boy have I been struggling to get my motors running to MY satisfaction. My philosophy is to make all the electronics first and then to decide on the hull around it. I am now a year overdue and not all of my fault. Had a few bad hiccups what nothing had to do with this project. Like a daughter having a head on collision with a 16 seated taxi, which took some of my time. (She is completely recovered) etc.

Some of you have been asking what happened.

No, the project is still on and it will take me a few years. But I have to solve my problem in having a brushless motor starting from 1 r.p.m. without stalling. Most controllers on the market starts at 20 Volt and go up to 48 Volt. Not suitable for me. However I enjoy it to experiment and write the software myself.

The good news for me is that somebody is experimenting with a similar size boat not far away from me and has made a H bridge for a brushed 5 Kw motor. If every thing fails, I will copy him and use a brushed Mars motor.
I have bought 5 brushless motors to experiment with.

Some very good information came from a local marine person who stated that they had a problem with their 25 feet yacht and were able to cross a bay with a 2,5 HP motor, close to Cape Town.

Another website gave me the best information.

http://electricboatdesign.com/database/

This website gave me the confidence. However I have to figure out for myself, what power is needed when I have a reasonable normal choppy sea with sunshine in this area. Not at the North pole or South Pole or at the North sea. Here, were I will have to feel save with what I am building.

Bear with me , as soon I ma ready I will have lots of questions. Jeremy, did you see the article of the 100kg single seater aircraft with a 13,5 Kw brushless motor at 1400 rpm doing up to 500 km distance?. (Batteries weight is 100kg) Thanks Brian, for the good news that most likely within 4 years Lithium batteries will carry 2 to 3 times the power than today. ( Batteries and battery technology)
Bert

 

Bert,

My controllers (used with big RC model outrunner motors modified with internal Hall rotor position sensors) start from just a few rpm and run smoothly up to maximum. I can run the motor on my solar boat down to around 50 rpm quite happily.

The RC model controllers won't do this though, as they need a bit of motor speed to get enough BEMF to sense.

I've been following the development of electric aircraft closely, Bert, although I believe that the range claim of that one is still a bit optimistic.

Jeremy

 

Thanks Jeremy for the info, maybe I am to optimistic to get it as low as 1 rpm. Your 50 - 60 rpm ( 1 per second) maybe more realistic. I use 36 Volt and with that board I made for the article "super capacitors" in brian's battery thread, I regulate the supply voltage and with the PWM, I regulate the pulse width. Very jurky at low speeds. I wonder why a brushless motor manufacturer has not come up with 2 motors in one, but then shifted by 1/2 magnet distance and 2 Y controllers. i.e. the torque flow would be much better controlled, without too much jurking. Maybe in the future when more and more power brushless motors are used in other applications other then RC models.
I will have to move on and accept that 60 rpm will be the lowest I can go.
Bert

 

I am slowly ready to start building the hull. My garage was to small, 6 meter long only, I needed to create more space and have removed all soil and grass and placed paving bricks, to allow me to build the boat in front of my house. I will have to design a kind of shelter under which I can build the boat. Some people have given me some excellent ideas, but now I have a question.
I know the answer. As much as possible space, however I love to hear from people who actual have build a boat in the garage and had to work under limited space conditions.
Here is my question to those builders. WHAT IS THE ABSOLUTE MINIMUM SPACE between the hull and the structure to be designed by me around the hull, to make the boat.
I like to hear from people who can say, I had 2 feet and 80% of the time I was in trouble because of this or that. Or I had only 1 feet and got myself only once in trouble. Your experience is greatly appreciated.
Bert

 

I haven't followed this thread, maybe some things have been discussed. It might depend on what you make it from as in wood, fiberglass, steel and how you go about working those materials. You need room for your tools and your body to use the tools. You need more room for using a longboard than an electric grinder. Spaces can hardly ever be too big. Use a wall or a truck or a similar sized boat and pretend you're working on your boat, go through the motions and that will give you an idea. If you have to use ladders, they take up a lot of space, plus your body.

I would say 2 feet at the least, if you have to get on your knees and face the boat to do work, you need at least 3 feet.

It might depend on the shelter and your weather also. If you can roll up the sides to give more room when needed and the weather permits, you could be stingy on space.

It might also depend on what sort of work you are doing in the shelter. If you have to cut and maneuver sheets of plywood around in your shelter you might need more room than if you cut stuff in your driveway or garage and just use your shelter mostly for assembly and finishing.

 

Thank you SamSam, it gives me some inputs to make a decision.
It will be a fibreglass over wood. I am in two minds. Should I have a company to make a boat cover, which can be later on used when the boat is finished and take it off , when working on the hull. The advantage is, that I will have all the space available for the work. Or do I make an electric 1/2 inch pipe frame system and bend it, covered by a plastic sheet of 250 micron thickness, which restricts me to a certain extend.
I have the tools in a workshop in the basements and a table saw for cutting in the garage. The beam will be just over 8 feet, 24 feet long and approx 6 feet in the beginning, before turned around. When turning the hull around, I need to place my contraption with the block, to lift the hull and turn it over.
Thanks for your response.
Bert

 

What about looking into the plastic pipe frame covered with thermo plastic and on swivel wheels. It should be big enough sothat you can work around it and on it but easy and light enough to maneuver when larger jobs have to be done. I would also suggest white opaque plastic for lighting and privacy. What do you think Bert?

 

Thank you
That is not a bad idee. I have concreted 4 x SS eyes in the concrete blocks to secure whatever. Now I can use those eyes and secure this moving tunnel during the nights and when there is too much wind. I could then move the tunnel away when working on the boat and move it only away if needed. Excellent idee Anton59.
Bert

 

No, the dream did not got shattered, but I have some bad nightmares. I received the motors ordered beginning last year, in February this year and made the controllers for them. Those two are additional to the 3 motors I had already purchased previously and did all the testing on. I also ordered during the course of the year, French and Indonesian marine plywood. But now my problem. I accidental shredded the material list of the Fisherman 18, recommended at the end of the day by the forum, to make this Fisherman 18, due to his low power requirement design. I wrote an e-mail 2 weeks ago to New Zealand and asked for help.
“Hi There,
The other mailbox seem not be in use anymore, as I did not get a short reply. Here my repeat request. Your help is greatly appreciated. The 1 page was accidental shredded by me. Sorry for that. Would you be able to scan that one page material list in and attach it to an e-mail ****** or fax it to my phone/fax number ++27 **********
Any cost, I will pay this into your account or settle with the credit card.
Best regards
Bert”
Nothing happened, thus I wrote another e-mail and received a very snotty e-mail, that they had no time, as they received hundreds of e-mails and I was placed at the end of the list. That was 2 weeks ago.
The time it took to wrote the –mail, one could have attached a scanned in copy to a blank e-mail and it would have taken less than the time to write this snotty e-mail. I offered to pay for it (within reasons) , as it was my fault. I even gave my fax number, in case he could not scan the page into his computer.
Thus, I have no alternative than to reduce the Hartley 28 by 13%, to keep the primary stability and I will have to reduce the length of the boat by 30%. Crazy? No, the boat will be proportional a little heavier, but the width is not reduced by 30 %, but only by 13% and thus the primary stability as pointed out by Tom is not an issue. Yes, I will have to arrange internally the layout, but that is also not an issue. But at least I have all the drawings and the material lists, which will be my basis. All in all I have invested some few thousand dollars, and am determent to build something what will sail.
However I have one question for the forum. From the photo one can see that I connected two Brushless motors without batteries. Try to image the one motor having wind blades, mounted in the mast and the other motor mounted in the water with a screw. This is ADDITIONAL to the 2 screws mounted on the motors connected to the controllers and batteries.
Between the “floating” 2 motors a 3 core thick cable.
If there is lots of wind, it will help the other 2 motors connected to the batteries to take it easy. If there is no wind, the 2 motors connected on the batteries will also have it easy, as the waves will be very small. It there is lots of headwind, the DC Brushless motor on the mast, acting as a generator will be cooled by the wind and supply at least 2 KW to 3 KW of extra power.
Do you think it will work?
(The extra third motor will be lowered in the water with the rudder, only when extra power is needed)
Bert