First solar powered circumnavigation

Some people are tired of having safety crammed down their throats. So much is overkill nowadays. And you probably don't want me started on the emissions era in the 70's. there is no way they really all thought that lowering the compression and killing the power would make them more fuel efficient and clean running. That was done to decrease fuel mileage so someone with connections could take advantage of high fuel prices. That alone set cars back 20 years. People that knew better were paid to forget, and to teach incorrectly. Today's consumer is fed so full of crap, they don't know what they want. We do get a lot of advances and neat stuff, but are they useful or just an expensive distraction? Even a band aid.

You can get the same power from an inline 4 that you can from a v8 at the same rpm? And you can get 20 kW from a 4.4kW engine? You've just invented free energy, and blown away the scientific world's model of physics.

A v8 is going to output far more power than the inline 4 at the same rpm, so of course the torque will be much higher from the v8.

hp(i4) = rpm(same) * low torque
hp(v8) = rpm(same) * high torque

Who do you think designed that dyno, and those engines? Every single piece of every single one was designed by an engineer, to work as a system designed by an engineer.

You lack a basic understanding of what power and torque even are. Ask your engineer friend if "torque is power" as you said previously.

I didn't state that it would be the maximum that either could produce, but yes it is fairly simple to build a 300hp inline 4, and that same 300hp is easy as could be in a v8. camming them to peak at the same rpm isnt hard. They will have different torque. Slap a similar hp v6 and an inline 6 in there and see even more different torque numbers.

I never denied the importance of engineers. Never said that y'all never did anything. I understand that we have a lot of cool stuff because of engineers. Engineers just all have that closed minded attitude towards anything that doesn't fit per the "rules."

Torque is power. If you need to move something heavy, you need power. Do you want the Holden Ute or the old tractor? Or the diesel truck if speed is needed.

Looks like a pretty nice boat. We expect more information.

No. If you have the same rpm, but different torques, you have different power, by the very definition of power.

Oh dear. Here is the root of your misunderstanding. Torque is NOT power. (Ask any engineer you like: your friend, your step-father...)

You can have high power and low torque (high rpm, think of top gear in your car), and you can have high power and high torque (low rpm, think of first gear in your car).

The units of torque are force * (arm)length. You can think of it as "rotational force".

The units of power is joules (or calories in imperial) per second. This is the amount of work you can do per second, and that work is force multiplied by the distance that force has been applied, which is how far you've rotated.

So power is torque * rpm. If your torque stays the same but your rpm doubles, you do twice as much work every second. Or instead if your rpm stays the same but your torque doubles, you also do twice as much work every second.

You need high torque to pull something heavy, but if your power is low your rpm must be low (to give high torque), which means you will pull that heavy object very slowly.
Higher power means you can have the same torque, but increase your rpm, and pull the object faster.

How many hours is it good for? Neat looking little boat. I have wondered about how an electric would work as a tender. I'm not fond of having gasoline on a larger boat, so I like the idea of a diesel or electric tender.

This is back to my earlier point about the hp wars and manufacturers raising rpm to make hp, and moving torque to high to be useful. Your engine is doing more work, thus more wear and tear, to preform the same task. If you want to know how well an engine works, what kind of real, useable power it makes, you need to know its powerband. This takes both peak hp, peak torque, and the rpm's they occur at. If peak torque is at 6000rpm and peak hp is at 7000rpm, it's not very powerful outside its element. If peak torque comes in at 3000rpm, peak hp at 6k, or even 2 and 5, you have more real power. That counts more than an arbitrary peak hp number.

I'd be happy to continue this, but you'll have to go and learn what power and torque mean first - it's not possible to have a meaningful discussion about concepts that aren't understood by one party.

Re. my highlighting of your quote: this is wrong. That is not what "power" means.

And peak hp is not an arbitrary number.

In an automotive application, what is going to make a vehicle move better, good hp at one set rpm, little or nothing before and after, or a lower hp number that is available over a range of rpm? Maximum hp means nothing if it can't be used in its application. In a car, speed (thus rpm) vary greatly. Having a greater average over the range of operation will be more powerful or better suited to its purpose. If you are lugging until you hit a spurt of power, it's gonna be about useless. As I've informed you already, peak hp is useless without an idea of its range of power in an automotive application. A generator, pump, anything with a constant operating speed it has more use, but even then, torque matters too.

Cool beans, glad you found a neat project. I'd be very interested in knowing how much sq ft of solar panel it would take to power something like that. I'll be looking for you build thread if you post one.

It depends on how much power the batteries he installs in it!!!!!!!!!!! hehehe

Lots of variables, power, speed, light, cloudcover. I would consider it good if it cruise for an hour or two, then recharge a small battery bank while on the hook for a bit, then cruise back. Using solar as supplemental power. However it works out, it will be a nifty picnic boat.

I believe they go a lot longer than that without any solar panels. Up to 6 hours if memory serves me right, but they only cruise at around 6 knots....35NM range rings a bell....

I didn't know if Norseman intended to keep a full array of batteries, use less and solar supplement, or full solar with a minimum of batteries. Or full solar over a stack of batteries, feed the motor 96volts and see what she will do. However it's done, it would be neat to have an electric boat that never needs to be plugged in.

That's entirely possible, but you get into cost versus benefits. Price of solar panels, etc etc..... my theory is a little different. I'd rather have some solar regeneration, but also a very small diesel that could power a battery charger and you could run off of the diesel electric if there's no sun and if you've drawn the batteries down too much......... but in their origional form it's just an electric boat and I believe the specs were 6knots, 35 nm on a charge. There's a few running around Ft. Laud. Top speed 6mph, 3.5hrs at top speed, 7 hours at cruise speed for most models.....I couldn't imagine what cruise speed would be if top speed is 6mph......LOL I'm pretty sure this is what he bought
Boat Models | Duffy Electric Boat Company

I'm with you about having a diesel genset. It adds versatility. The amount of solar required interested me. I was thinking a full canopy worth of panels might be enough, but yes, costly. The stock boat sounds like it would be neat for small lakes and very slow moving rivers. A sub 4 knot cruise would probably have me taking a nap and hoping my destination was in sight by the time I woke up.

The other issue is weight and stability. A full panel of solar panels on the hardtop and stability is going to be effected as well as weight and people carrying ability..... Although it seems like that little displacement hull should move a heck of a lot faster with 48hp. The 26' Navy whale boats were faster than 6 mph and had I think 26hp diesels.....