Turning Clock or anti clock wise

You both, tunnels and you are correct. Original the heavy box was planned to be part of the keel and the shaft would have been longer. But, time is flying and I decided to buy a boat and modify the part of the keel wherein the gear/motor was placed., instead of starting from scratch. In the front of the prop there will be a water dynamic cover, which makes the turbulence less. But at the low revs and speed, time will learn whether I have to start from scratch again. The same applies to the front of the box, but that cover has been made already. refer attached box.jpg file. In the mean time I have fun.
Bert

 

I just seen the picture of what it is or was or is going to be !

Its and alien !
With some glass and some clever thinking you could make it work quite easly with a scoop arrangement to draw the water into the centre and feed the prop and would completely do away with all the disturbance then a shroud over the top to draw yet more water towards the prop .
will have to think on that over night but it would sure as hell be a lot more efficent and better that whats there now !!

 

Thanks Tunnels, Actual I was planning to make a type of "tunnel" arrangement in combination with a dynamic cover in front of the prop connected to the box. I love to see what you have come up for an idea. Sleep well and trust that you will have some sketches for me when you wake up. Thanks
Bert

P.S. I was planning to make it from aluminum and then anodize it.

 

Bert I am just a bit lost here,

what are you hoping to achieve
what kind of horsepower
what kind of speed
what kind of running hours

the boat looks like a standard speedboat?
do you want to fish or do you want to cruise?
will the boat be on a estuary or are you hoping to go to deeper water?

I am just interested to see what your goals are with this project.

 

Ok i have come to the concussion its better to stick some polystyrene to the channel with the shaft sticking through it and shape it from there its flowing lines you need nothing with sharp bumps and lumps anywhere !! the back edge from the shaft to the top needs to come to almost a blunt point so to speak , once you get your shape to how you like it epoxy glass it and then when you have enough glass remove the whole thing and use thinners and scrape out the poly styrene .
I Have doodled on bits of paper all day and just keep coming back to the same thing all the time .
No you shouldnt need to even think about a shroud of any sort if anything gets caught up it would wind the whole thing off and into a million bits !!. Just 4mm thick of solid glass should be ok with epoxy resin over the polystyrene foam !
The part closest to the boss of the prop should be the same diameter and just a good transition from one to the other with as lttle disturbance as possible , The shape for the upper part should go all the way as high as is practical !!air could track down the back of a blunt shape so bring the back to a point sort of !! and you shouldnt get that problems !!
Strange things happen under water !!!:idea:

 

Hi Manie, I had already left for Johannesburg and have only now a chance to respond. Although already late, I give you a quick reply.

I am not going into a dispute, as all the above has been answered already in the previous threads.

1) All what I can say is, that I have made provision for building two DC brushless motors in tandem into the box, should it be necessary. They can deliver sufficient push. But batteries are a problem.

2) I just read that a speed boat was made with 562 Kg of Lithium batteries, which could deliver for 10 minutes 1,2 Million watts via 6 high voltage in tandem motors.

3) I like to power the boat with the least power. The battery technology is being held back.

4) I am not a fisherman, nor go cruising and will only have the boat on the sea with full approval of the local authorities. I wonder why you want to go to Mozambique to put your boat into the sea. There are a number of places just north of Lorenzo Marcs to put your boat into the water, but why?

5) The boat is a cabin boat.

6) I will first thoroughly test the boat before I go anywhere.

Trust that I have answered your questions.

Bert

 

Hi tunnels, Thank you , I have the above indeed in mind. However I prefer to use aluminum. For several reasons. Sorry, but I flew to Johannesburg with the wife and came back late tonight again.

My speed planned for the boat is so slow, that I wonder whether I will be ever be able to test the difference. But time will learn. Do you have any chance to attach a sketch to your reply thread?
Thanks and best regards
Bert

 

Hi Bert, enjoy the project - it's yours and you are having fun.
The rest will sort it self out as you go along.
As I am still busy doing my proposed river adventures and explorations all over South Africa, I also am far away from going to "LM"
Lots of local waters to enjoy.

 

Bert just some data for what it's worth,

The 30lbs thrust MinnKota pushes my boat at 2.1 knots, calm water inside the marina, no wind. The boat was fully laden ready for a trip = 750 kg approx with me on board. I must add that we were very surprised to see 2.1 knots on the GPS, way more than expected.
Against the wind - forget it.

It is a toy, but most certainly better than trying to row, I dont know how many amps but you may be able to figure it out. 12 volt.
It will get me to the side easily, I wont be stuck in the middle.

 

Not bad, I am having 75 kg trust at 40 Volt on paper, but have not been able to verify this. The boat + load is maximum 430 Kg. It has at present 70% buoyancy. However I will add an extension at the transom to get rid of some of the drag. The buoyancy will be higher. I have no idea what speed to expect. It will still take me quite a while.
Bert

 

non informative drivel posted then deleted.

 

Well according to some information from another thread. A human can produce 120 watt for a long time and with 150 watt for a short period of time. I assume that in your case , you would have at least 10 Amp, thus some 120 watt. You should measure it one day. If you want, I can post you some 10 Milli Ohm resistors, which you must than solder and place parallel and measure the current with the voltage over the 0.001 Ohm (10 parallel), it gives you an idea. You need to be able to measure up to 100 Milli Volt with your Voltmeter. Alternative, I will cut a small pcb with a cut in the middle and solder those 10 on it for you. I like to know at what power made you traveling at 2.1 knots. It gives me some more information for myself.
Bert

 

This depends what kind of humans and how long times you are talking about. A top athlete can produce 400-500 W for an hour. A fit person can produce about 200 W for an hour. 150 W seems very low for "a short period of time", if that is far less than an hour.

You can get a feeling of the power you can produce from this bicycle power calculator: http://bikecalculator.com/veloMetric.html

 

Hi Joakim, Thanks for the info.
Half of the readers are over the 40 years of age, I guess. Most of us have not done too much sport daily, thus I stick to the info from, I think it was Porta, who mentioned this in one of his threads. That does not mean I don't agree with you. You are fully correct probably. But how many fit people are there on this world? At 72, I bet you, that you will outrun me and produce a lot more than 120 watt. Bert

 

Hi Lewis, Yes indeed, the very rare word deasil , is clockwise. It was original used as from the year 1771 and had some Irish / Scottish origin. You must have been in a literature mood, when you wrote the thread. (and then you decided to delete)
Now, what about giving me a sketch on how I should channel the water flow to the propeller, with a funnel or tunnel, or whatever!! to reduce the drag. Bert