Anyone convert their freewheeling drive shaft to a hydro turbine?

[Cadence]

Originally Posted by VinnyVincent

It's permanent for me because I just bought a new outboard for it.
My concern would be resale if an owner insisted on putting an inboard in...although it's unlikely with a cheap boat like mine.

The beauty of this alternator idea is that I can leave the shaft on and have it be functional. I get some use out of it and it doesn't hurt resale value...it's also likely cheaper than paying to have it sealed off.

I'm thinking about using a bicycle generator instead of a car alternator though...not much of a price difference and the bicycle gen. uses permanent magnets instead of electromagnets like a car alternator, which use up a decent amount of power.

How are you planning on regulating the bicycle output of 0 to 40 volts.

[Arthur Garfield]

May have already been suggested ,though my thought is use the prop with shaft coupled to DC motor with controler that'll switch DC motor to generating when under sale power and freewheeling.Add battery system to use DC motor powerered prop in and out of anchorage/marina.Add solar panels for further ranging under prop power.Now you can sell outboard gasoline motor.Some costs but zero noise nor outboard repair no nada.This has been done quite a few times already.


All the Best

[VinnyVincent]

Originally Posted by Cadence

How are you planning on regulating the bicycle output of 0 to 40 volts.

With a wind turbine voltage regulator???

[Jim Cate]

Originally Posted by Cadence

How are you planning on regulating the bicycle output of 0 to 40 volts.

With a small source like this, as long as the battery is not fully charged, the load will pull the voltage down to a reasonable charging value. Simply monitoring the system voltage and disconnecting the charger when the voltage rises to ~14.8 or so will be completely adequate. In practice, that will not happen often (at least in my experience!). So, no controller other than the operator's attention and a switch.

Jim

PS In fact, a diode in the circuit will be required to keep the generator from acting like a motor and discharging the battery when it's output voltage is less than battery voltage.

[a64pilot]

Since cost is an issue, why not a small automotive alternator from a Junkyard, maybe $10? Self regulated etc.


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[VinnyVincent]

Originally Posted by a64pilot

Since cost is an issue, why not a small automotive alternator from a Junkyard, maybe $10? Self regulated etc.


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I thought alternators produced alternating current that would need to be converted into DC, requiring additional equipment, where I could just hook the bicycle generator directly to the battery since it is DC?

[Sailmonkey]

Originally Posted by VinnyVincent

I thought alternators produced alternating current that would need to be converted into DC, requiring additional equipment, where I could just hook the bicycle generator directly to the battery since it is DC?

Alternators have internal rectifiers that convert the AC to DC.

But my question is what is keeping the shaft in the boat now that there's no engine to take the thrust/pull and how do you keep the shaft centered in the tube when side loaded with belts?


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[chris07732]

You don't mention where your boat is located, but up here, east coast, it's a maintenance nightmare keeping prop/shaft free of barnacles. In the south, much worse. Your efficiency will drop dramatically with any growth on prop. You seem to be trying to make a decision on the project based on lowest cost when your goals should be to minimize maintenance so you can go sailing

[HappyMdRSailor]

Originally Posted by Sailmonkey

Alternators have internal rectifiers that convert the AC to DC.

But my question is what is keeping the shaft in the boat now that there's no engine to take the thrust/pull and how do you keep the shaft centered in the tube when side loaded with belts?


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You barely edged me out SM!!!

Vinny... As salty mentions, the above has been a concern of mine as I read through the thread... Your shaft was meant to be held in lateral position by the tranny coupling... It's highly likely that you'll need to add a carrier bearing of sorts... or... leaky... leaky...

[VinnyVincent]

Originally Posted by Sailmonkey

Alternators have internal rectifiers that convert the AC to DC.

But my question is what is keeping the shaft in the boat now that there's no engine to take the thrust/pull and how do you keep the shaft centered in the tube when side loaded with belts?

That's another issue I hadn't quite worked out yet.
The old motor mount forms and arch over the top of the shaft. I was thinking about bolting on some type of brace with a bearing to hold the shaft centered when the side load from the V belt is applied.

The only thing currently keeping the shaft inside the boat is the old piece that bolts onto the gearbox...here let me see if I can upload some pics...

Originally Posted by chris07732

You don't mention where your boat is located, but up here, east coast, it's a maintenance nightmare keeping prop/shaft free of barnacles. In the south, much worse. Your efficiency will drop dramatically with any growth on prop. You seem to be trying to make a decision on the project based on lowest cost when your goals should be to minimize maintenance so you can go sailing

The boat is in Texas. It is my first cruiser and first boat that stays in the water, so maintaining it below the water line is still new to me.
Cost isn't my only priority. I certainly would rather spend a little more on solar if I am going to have to go through great lengths to make this prop. shaft idea work and to maintain it.
The question is, how much solar panel wattage would I need to purchase to equal the same charging power as the prop. generator?

If it is equivalent to 100-200w of solar then it would make more sense to spend a little more on solar.
Between having to jury rig some type of brace to keep the side load of the belt off the prop. shaft, not having a voltage regulator(means one more thing I will need to worry about), having to keep the prop. cleaned and put zincs on the shaft, moving parts, the fact that I can't really remove the setup from this boat and use on a future boat, plus the fact that when done right it's not going to be a whole lot cheaper to buy a 100w-200w solar kit...it would seem solar would be a lot better.

But if it cranks out as much as maybe a 500-600w or higher solar panel setup would, that would be a significant savings over solar and possibly worth the extra work and maintenance involved.

[HappyMdRSailor]

I think you hit it on the head Vin...

As Jim offered, his power generation wasn't linear... Solar OR shaft gen... You ain't hittin' 100% rated output...

There's hassles, install, component costs with either... I think your idea does have merit though...

Outta sight... Somewhat straight forward... Somewhat reasonable cost...

Do the reviews on the gen look good?

[Sailmonkey]

How about the shaft seal? Is it dripless or are you going to be constantly fighting to keep salt spray off of the generator?

I think this can work, but I believe you'll be into it more than the cost a a 100 watt panel an regulator. If your concern is keeping power up for a day or overnighter, then I bet you'd be better served with another battery and a single solar panel.


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[VinnyVincent]

Originally Posted by HappyMdRSailor

Do the reviews on the gen look good?

Yeah it had some pretty good reviews, but I assume most of the people were using it as designed, on a bicycle...
They have a chart that shows amps at RPMS. It shows that it produces 6 amps at 1000 RPM and 10 amps at 1500. I think this would be achievable with a 10" pulley bolted onto the shaft going to the pulley on the generator.
The reviews did say that the chart was accurate as well.

Here are some photo's of the shaft. You'll have to excuse the mess, this was right after I purchased the boat and I had a lot of cleaning to do


This is a close up of the shaft. You can see that the piece that used to bolt onto the gear box is the only thing holding it in.
While underway this bottoms out. Should I be securing this somehow? My thoughts are that it could eventually come loose under the pressure and the shaft could slide out, causing a catastrophic leak...



Here you can see where the motor mount forms and arch.(it's that thin piece of 1/4" steel that you see over the top of the red tip on the yellow squirt bottle) The shaft has enough play in it to telescope out directly under this arch, which is what I had planned to bolt the alternator with the brace for the shaft to...

[SteveSails]

IMHO the cheapest solution is to remove the shaft, glass up the hole, and get a solar panel to charge the battery. You'll be happy with the sailing performance if you did.

The generator sounds simple in theory but in practice not so much. The bronze stuffing box can't be used as a bearing to take any of the side loading, only to keep the water out. So you will need to fabricate a bearing system for the side and thrust loads, a mount for the pulley and a bracket for the generator. Do you have the ability to fabricate the metal parts and like to tinker? If so then go for it otherwise it's going to cost a few $$$ to get someone to do the work.

Whatever you do don't sail with the shaft as shown in the pictures. The unsupported shaft will wear out the packing in the stuffing box and start a leak that might be hard to stop, more than one boat has been sunk that way. At least tie the shaft off so it doesn't spin or leak.

Good luck,

Steve

[VinnyVincent]

Originally Posted by SteveSails

Whatever you do don't sail with the shaft as shown in the pictures. The unsupported shaft will wear out the packing in the stuffing box and start a leak that might be hard to stop, more than one boat has been sunk that way. At least tie the shaft off so it doesn't spin or leak.

That was one of my concerns. I plan on hauling the boat out this coming spring and will likely seal it then, unless I do the generator thing... but at this point I am leaning toward solar.

Until then I suppose I will tie it off. I am just wondering if the load from it being tied off would also create enough lateral pressure to cause a leak, even though the shaft isn't spinning?