Solar thermal propulsion.

[Herreshock]

Yes, but irrespective of the type of boat surely one should be looking for an efficient power source? Even on our little 7' timber dinghy or the 10' poly Walker Bay, a 40lb thrust trolling motor gets the same speed as that Stirling engine which is on a much longer boat that should have much lower resistance at 3 knots than our smaller dinghies which have reached hull speed.

The trolling motor battery charges easily with the power from 200W of solar. Some people claim to have good success with just having solar panels in the dinghy to charge the battery. Solar panels are much more easily handled than large mirrors - ours just hang off the pushpit where they don't interfere with deck space or rigging at all.

No petrol nor electric is efficient since it gets a big production chain and plenty of energy losses and CSP solar space isn't an issue.

You look more like a PV panels salesmen

 

[Herreshock]

Found on Youtube pretty cool video about 25 kw solar Stirling system from 40 years ago.

Claimed efficiency 24% which is similar to good PV panels. It seems that in an era before cheap PV panels those systems were considered for industrial scale solar power generation.

However putting that thing on boat would not be very practical. A boat big enough to carry it safely would be severely underpowered with only 25 kw. It would work fine as a tech demonstrator boat that can slowly cruise around calm lake on sunny day. Completely impractical as auxiliary propulsion for average cruising sailboat even if you could get away with only 5 - 6 m diameter system. PV panels are just so much better in boat application.

Petrol or electric isn't practical, it's rather a consumer monstrosity and these parabolic CSP can be mounted on deck just over the bimini in calm weather and stored easily and folding it like petals

 

[CT249]

No petrol nor electric is efficient since it gets a big production chain and plenty of energy losses and CSP solar space isn't an issue.

You look more like a PV panels salesmen

Since I buy solar panels and don't sell them, no reasonable person would think I'm a salesman.

Space is an issue on many craft. You have to be able to come alongside wharves, put out anchors, back up, raft to other boats and do that sort of task - and do it without having a mirror that could cause reflection problems. The sort of mirrors pictured are impossible to use on dinghies and yachts like the one I use my electric outboard on. Solar panels are not.

As far as the production chain goes, you have shown zero evidence that the tech you are talking about has a more efficient chain than the high quality panels and electric motors I use. One of the people we bought panels from has, for charity, been renovating 25 year old panels donated from an old commercial user and he says that they are all still working at very high efficiency and will do so for as long as he can see.

What alternative power methods do YOU use AT THIS MOMENT? Is your residence driven by solar? Do you get to work (if you work) by electric vehicle or human power? Do you have hectares of trees growing to improve the environment?

If you rely on fossil fuels yourself then it's hypocritical to complain about others using fossil fuels. So come on - do you do as you say, or do you just tell others what to do?

 

[Tomsboatshed]

Petrol or electric isn't practical, it's rather a consumer monstrosity and these parabolic CSP can be mounted on deck just over the bimini in calm weather and stored easily and folding it like petals

Theory and reality often are separated by the chasm of practicality. Petrol and electric systems offer proof of practicality day in and day out. There are a multitude of practical use cases offering a testament to such. Boats using petrol/diesel/ diesel electric have demonstrated the ability to voyage at the wish and whim of their owner; and that’s a major value for many who use them. Are your proposed systems capable of providing the same utility/value and is there a practical example of use in a 12- 15 metre trawler with live aboard accommodations for 2 and 2 guests and a cruising range of say 800 km?

 

[Herreshock]

Theory and reality often are separated by the chasm of practicality. Petrol and electric systems offer proof of practicality day in and day out. There are a multitude of practical use cases offering a testament to such. Boats using petrol/diesel/ diesel electric have demonstrated the ability to voyage at the wish and whim of their owner; and that’s a major value for many who use them. Are your proposed systems capable of providing the same utility/value and is there a practical example of use in a 12- 15 metre trawler with live aboard accommodations for 2 and 2 guests and a cruising range of say 800 km?

People shouldn't act by whim but adapting to conditions and for a reason, and the only reason sailboats exist for 5000 years is to transport cargo and at the same time people, not for consumer or tourists taking whimsical risks

Whim is a consumer induced behaviour and people needs to get out from the consumer mindset pronto, and just a solar flare or h.e.m.p would render all engines and electronics worthless

People needs to learn enginesless sailing even if having any kind of engine including CSP solar as there are plenty of protocols, manoeuvres and gear to sail without engine and with more safety than the average sailing title

 

[Tomsboatshed]

People shouldn't act by whim but adapting to conditions and for a reason, and the only reason sailboats exist for 5000 years is to transport cargo and at the same time people, not for consumer or tourists taking whimsical risks

Whim is a consumer induced behaviour and people needs to get out from the consumer mindset pronto, and just a solar flare or h.e.m.p would render all engines and electronics worthless

People needs to learn engines sailing even if having any kind of engine including CSP solar as there are plenty of protocols, manoeuvres and gear to sail without engine and with more safety than the average sailing title

I don’t really know what all that means, but it doesn’t really answer my question…

 

[Herreshock]

I don’t really know what all that means, but it doesn’t really answer my question…

Corrected, engineless sailing
You need and engine only in calm windless weather and for other scenarios there are engineless practices

The age of holding beer and pushing a button is gone and for good

 

[Mulkari]

Again bringing bias and fallacies, thats one stirling design between plenty of them and they haven't been researched much

Do you know a small parabolic concentrator can melt glass, metal, rock, etc? What information have you checked to claim to put a "many" meters CSP device??

And what do you want? A 500hp? A trolling motor is enough to power 3 knots even a 28 sailboat on calm water and if there's wind, the sail

An average size cruising sailboat say somewhere around 13 - 15 m generally have around 50 hp diesel. Maybe you could get away with 10 hp if inability to maneuver during strong wind in harbour is acceptable tradeoff. It would still be impractically large CSP device at around 30 - 50 m2 to equal puny Yamaha 9.9 high thrust outboard.

I have a 9.5 m performance sailing catamaran with 6 hp outboard which is considered underpowered by many yet there is no way I could mount a CSP device big enough to equal that outboard and still have room for usable sailing rig. At least with solar electric I would have the ability to charge batteries from PV panels, charge from marina outlet, charge from wind generator and hydrogenerator when sailing. Much more versatile system that although much heavier than outboard and 12 liter gas tank could be made to work for short distances. I often arrive to my dock after dark and have to travel up river for about 6 km to get there. Often no wind after entering river. Outboard works, solar electric with sufficient battery would work too. CSP wouldn't work, it also wouldn't work in a day with clouds while PV panels still works at reduced output and battery would give me short bursts of high power if needed for example to get out of the way of large powerboat on autopilot with no one looking at where they are going.

 

[Mulkari]

Since Stirling (or steam) engines doesn't care what the source of heat is a wood furnace would be far more practical. Much smaller and works any time no matter the weather. Still much more bulky and heavy compared to diesel, but at least steam is historically proven to work both as supplemental to sails and as primary driver.

 

[Herreshock]

An average size cruising sailboat say somewhere around 13 - 15 m generally have around 50 hp diesel. Maybe you could get away with 10 hp if inability to maneuver during strong wind in harbour is acceptable tradeoff. It would still be impractically large CSP device at around 30 - 50 m2 to equal puny Yamaha 9.9 high thrust outboard.

I have a 9.5 m performance sailing catamaran with 6 hp outboard which is considered underpowered by many yet there is no way I could mount a CSP device big enough to equal that outboard and still have room for usable sailing rig. At least with solar electric I would have the ability to charge batteries from PV panels, charge from marina outlet, charge from wind generator and hydrogenerator when sailing. Much more versatile system that although much heavier than outboard and 12 liter gas tank could be made to work for short distances. I often arrive to my dock after dark and have to travel up river for about 6 km to get there. Often no wind after entering river. Outboard works, solar electric with sufficient battery would work too. CSP wouldn't work, it also wouldn't work in a day with clouds while PV panels still works at reduced output and battery would give me short bursts of high power if needed for example to get out of the way of large powerboat on autopilot with no one looking at where they are going.

Anybody can move a 15m sailboat by towing it with a rope while swimming in calm windless weather. What means you dont need a big engine to move a sailboat in calm weather.


Nobody cares about your HP engine this isn't a thread for speed or people spreading bias

 

[Herreshock]

Since Stirling (or steam) engines doesn't care what the source of heat is a wood furnace would be far more practical. Much smaller and works any time no matter the weather. Still much more bulky and heavy compared to diesel, but at least steam is historically proven to work both as supplemental to sails and as primary driver.

Yes we can also use your boat as combustion materials for 1000hp stirling engine

 

[Tomsboatshed]

Corrected, engineless sailing
You need and engine only in calm windless weather and for other scenarios there are engineless practices

The age of holding beer and pushing a button is gone and for good

Did we run out of beer?

 

[Herreshock]

Did we run out of beer?

No, I'm delivering beer in my kitty stark for all the alcoholic nation lol

 

[Herreshock]

Less chat and some facts, here's a simple setup and i would rather use a fin propulsion system

This can be simplified by making the static gimbal or solar tracker with just a 2 movement pole in the stern for the box with the lense ("water filled" glass in the image) and using a cardboard funnel covered with aluminium deposition

You set course and adjust the gimbal or tracker to the sun and done and correct it every 30 mins every watch with sun rotation, simple and practical

It works for cooking, desalination, sterilisation, water heating, etc in flat water, anchored and even sailing well trimmed with little waves

To be used in rough seas for these other uses maybe it would need a circular 4 rings (2 for tracking and 2 for roll and pitch) gimbal and also the lense in the lower half like this one

No choppers any more

 

[Mulkari]

Anybody can move a 15m sailboat by towing it with a rope while swimming in calm windless weather. What means you dont need a big engine to move a sailboat in calm weather.


Nobody cares about your HP engine this isn't a thread for speed or people spreading bias

At what speed would you tow 15 m sailboat while swimming? A fast snail maybe have good chance of winning that race.

Less chat and some facts, here's a simple setup and i would rather use a fin propulsion system

This can be simplified by making the static gimbal or solar tracker with just a 2 movement pole in the stern for the box with the lense ("water filled" glass in the image) and using a cardboard funnel covered with aluminium deposition

You set course and adjust the gimbal or tracker to the sun and done and correct it every 30 mins every watch with sun rotation, simple and practical

It works for cooking, desalination, sterilisation, water heating, etc in flat water, anchored and even sailing well trimmed with little waves

To be used in rough seas for these other uses maybe it would need a circular 4 rings (2 for tracking and 2 for roll and pitch) gimbal and also the lense in the lower half like this one

No choppers any more

So there is maybe 2 m2 of combined surface area. Assuming ideal solar conditions 1000 w/m2 it would at best give about 400 w at propeller after conversion looses. It maybe could drive that boat at 2 knots in dead calm. Forget about going against current or maneuvering in narrow places in any wind. What about emergency situations like no sun, wind dies and your boat now is in strong current carrying it towards rocks with 4 m breaking waves or into busy shipping lane. Reliable power on demand is essential.

Why are you so obsessed about CSP power in application where it is ill suited for when literally any kind of combustion or battery powered motor is far superior. Even team of rowers would work better. For example Baltic sea where I sail for half a year gets little direct sunlight. and even in summer you can get several cloudy days in a row. CSP just wouldn't work reliably or at all.