Did a dream got shattered?

That being said...

If you could provide a drawing of the cross section of the boat, about in the middle, and one of the waterline that will help give everyone an idea what the form stability of the hull is without creating any copyright problems. But overall, you seem to have a grip on finding the VCG. Once you have that for your more detail design with the motor and batteries, you can venture a new post to ask for help in determining the stability curve (a rough one)... but for now, lets assume you will reduce the boat overall by 13%, and get on to other aspect of your design.

If you are doing coastal cruising, then you need to find out how to calcuate the range you can get for the motors you will use with what weight of batteries. Keep a safty reserve. That with your solar panels and your emergency sail should give you enough power back up.

The batteries, keep down low, will give you enough positive stability to right your boat in most case - you do not need 100% positive stability all around, as if there are waves steep enough to flip you over, they will also flip you back if you have some positive stability past the 90% role point.

Add to that enough closed floatation (compressed air in PVC seems like a less safe option than injecting closed cell foam by the way) so its unsinkable, and you will be as safe as you can get.

Oh, yeah, your cabin and all openings (and closing them) will have to be very solid so you can avoid having water enter those closed parts of the boat in a storm. Good pumps are not a bad idea too.

 

I flaged your post, and ask for the thread to be closed, or all the derogatory posts (including mine) to be deleted.
Your attitude make me do that when you say:

Shame on you. You don't belong here.
Daniel

 

Just for safety you should keep a small outboard, just in case.

 

I think this is very reasonable and well-spoken.

 

<Mod note: I've gone through and removed a half dozen posts from the thread which were insulting or way off-topic.>

 

Thank you Jeff, and my profound apology. In no way I wanted to negatively remark upon your staff controlling >> insults. But merely meant that it is technical and humanly practical impossible to police this very good and informative site 24 x 7. You and your staff has to sleep at some stage. Bring my apology over to your staff. And also the word "abuse" should have been "insult", it could be misunderstood. Also my apology for that.

Unfortunately I have some problems with equipment I have shipped 5 years ago to Norway and Sweden. This will take my attention for a few hours or maybe days. I will reply to all the questions and suggestions you all have posted and I will come back to you.

Bert

 

Thank you Grant to assist me. I will consider how to do it without that I feel that I do a copyright infringement, although nothing is mentioned as such on the plans. However I feel obliged to do so.

That is the crunch of the real problem. According to the program "PROP.CALC' from an English company who makes props, I only need 2 Kw to a enjoyable slow speed and I need 7 Hp or 5 KW to reach max speed at 1400Kg and 7,5 meter. 12 Volt batteries x 55 Amperehour x 4 in series and 3 parallel (48 Volt) times 2 banks means 15 KWh. Total weight 324 Kg and that is a little too much. If I go down in power, I will have to stay in the bay, which I am planning to do in anyway for the first year or years untill improved batteries have come out. This is when there is no sun. If there is sun, and I can get 8m2 solarpanels which has an efficiency of 18%, I could add some extra distance, but only on a guaranteed blue sky for the day. If there is wind, I also could add some energey, but again, is the wind a headwind or a tail wind. This will make a diffrence. Thus all in all, the first couple of months means only in the bay.

Here is the next technical problem I have to solve, in how to keep 324 Kg batteries in place and special should the boat flip.

Yes, indeed you are correct, and I will have to have further discussions with the port authority on how they want me to make it.

Moe Nie Worrie Nie (Don't you worry) It will be in the same way all sailing boats have their openings.

Bert

 

I was hoping that with two totally seperate motor systems and with a small emergency jib, that that should be enough. If I can avoid it, I like to keep diesel or gasoline (petrol) away from the boat. Otherwise additional legislation is again applicable. But maybe you are right and I have to add that also (extra weight is also then a problem)
Bert

 

And please let me ask, when, how and why could this propell your boat at a decent speed?

It is ALL just premature phantasies, do´nt you get that?

NO,

I have no intention to insult you.

No intention to destroy your dreams.

I am NOT the one who "shattered the dreams" as your thread was named.

But when will you wake up and grasp, that it is not possible what you are planning?

You "stay in the bay" while the sufficient battery packs are developed?

But first you buy the insufficient to go out to the bay?

You redesign (with or without the assistance of the pro´s here) a boat which by no means can bear the burden of a complete set of "alternative" power supply, be it PV or wind , or what so ever on the market (I include the unaffordable gimmicks).
Then, quite late, you comprehend that a backup IC system might be necessary.
And the, now overly burdensome, weight of this system is what?

Bert
your dream will not come true! Get that!

You might think I am a ******* and not the one to assist you. Right. I am a ******* (at least when you ask my competitors), but I am not against your plans! They are just not in balance with todays technology. And for sure not in line with a homebuilt.
You would ruin all your entire life, would you stubbornly follow these plans.
Please believe me.
We have seen many of such tasks over the decades, yet we have to see one coming out to success.

Go and build a boat!
Do it to a proven and affordable plan!
Do it to the method required and recommended!
Do it without the NEED to improve anything!
And do it soon!
You otherwise will be caught in your own inability to see your restrictions!

My best regards
Richard

 

Bert--true- your batteries could be your ballast to some extent.
it shouldnt offset your weight too much since you would need some ballast anyway. on a civil sub as an example- a lot of ballast weight is in the batts.

keeping the batts in place that shouldnt be a big deal- there are many easy ways to secure batts...straps- buckles- seatings etc. should you turtle--they will stay in place with simple and effective brackets or straps etc.

 

Actually, you may have hit the nail on the head. As you notice on the drawing Hartley4.jpg , I have a de-tachable rudder. I will see whether I can add the lithium batteries and the motor in the rudder, like I have in the rudders in the keels.

Folks, 20 years ago there very view electric boats, today there are thousands of electric river boats.

5 years ago, there was no electric speed boat, today there are a few of them having a 50Kwatt watercooled motor. ($ 28700.00 each)

There are no offshore rough sea boatsplans avialable (my size of 7 - 8 meters) and 2.50 meter wide. Why can I not pioneer and find my way to a possible workable solution? Why not ? Don't you have dreams? If you don't have dreams, I will be very surprised. (and feel sorry)

Bert

 

Check Rolls Royce marine section. I know its a little too large for your project.:

 

Yes, something like that. I visualise a removable rudder, with piping system and 200 gram 12 Ah batteries (As I have experimented last year) and a small motor of 1 Hp . According to PROP.CALC I could do with a 1 HP engine and a displacement boat and 1800 Kg an acceptable 4 Mphour. Thus for an emergency, when there is no wind (for my emergency jib and windgenerator) and no sun (for my solarpanels) and thus flat water and 2 flat main battery banks, I would be able to do a distance good enough to get into sheltered waters. Bear in mind only coastal, no ocean crossing. But to get myself into such a bad situation, I should hand in my skippers licence
Bert

 

Let me explain why I have a removable, detachable rudder. In view that I will have two props , I will steer with the variation of the speed of the two motors. I don't need a rudder to drag along and create friction. But I need a rudder, should I need to use the jib for whatever reason.

 

Bert after these last two posts its pretty clear that you are not really interested in achieving a good design. It seems that you are more interested in being a big kid and playing around with your very own ideas.

Go for it. Nothing wrong with that if you have the money to waste. Sounds like you have already talked to the harbor authorities and peeked their interests like you have here.