On our monohull boat we chose an approach to comfortable bluewater sailing without a generator. In the attached PDF we outline our design specifications and the experience of several years of sailing and living on the boat.

A great real-world review. Thank you.

A few comments.
1. Did you consider a hydrogenerator? We thought about it for the Pacific but eventually decided we couldn’t justify the expense.

2. LiFePO has made a huge difference to our cruising when compared to our previous AGM’s. Don’t underestimate the advantages.

3. Agree about modern solar and wish we had added rail mounts to our similarly sized boat.

4. Less impressed with our wind generator but it may just be too old and inefficient..

5. We do have a diesel generator which made things much easier in the high latitude legs of our trip where solar is not much help.

6. Not keen on carrying petrol to feed a petrol generator having abandoned petrol outboards in favour of electric 12 years ago.

Thanks for sharing your thoughts.

Simon

+x

 

Dietmar.Segner - 15 Feb 2024

On our monohull boat we chose an approach to comfortable bluewater sailing without a generator. In the attached PDF we outline our design specifications and the experience of several years of sailing and living on the boat.

+x

 

Simon Currin - 16 Feb 2024

A great real-world review. Thank you.

A few comments.
1. Did you consider a hydrogenerator? We thought about it for the Pacific but eventually decided we couldn’t justify the expense.

2. LiFePO has made a huge difference to our cruising when compared to our previous AGM’s. Don’t underestimate the advantages.

3. Agree about modern solar and wish we had added rail mounts to our similarly sized boat.

4. Less impressed with our wind generator but it may just be too old and inefficient..

5. We do have a diesel generator which made things much easier in the high latitude legs of our trip where solar is not much help.

6. Not keen on carrying petrol to feed a petrol generator having abandoned petrol outboards in favour of electric 12 years ago.

Thanks for sharing your thoughts.

Simon

+x

 

Dietmar.Segner - 15 Feb 2024

On our monohull boat we chose an approach to comfortable bluewater sailing without a generator. In the attached PDF we outline our design specifications and the experience of several years of sailing and living on the boat.

Simon, I completely agree. If our AGMs give up it will be LiFePO. However, electricity first needs to be generated, even with lithium. I think their biggest benefit is the fast charging with alternator or generator and less losses. In addition to the cost of a What&Sea we also heard quite a bit of problems with saragasso weed, floating debris. And 90% of the time we are at anchor and then it is in the way for our dinghy. Without our wind vane we might have obtained one.
dietmar

Dietmar,
Thank you for very useful paper.
Mainly, I agree with Simon except that we have found a hydrogenerator invaluable.  We have had a Duogen3 for about 9 years and until last year when a bearing collapsed on the wrong side of the Atlantic we have not had to think about power generation while on an ocean passage.  It's loss, combined with very little solar energy on a West to East crossing necessitated running the engine for a couple of hours most days.
(Another plus point of the Duogen is the possible deterrent effect to orca interaction of an impellor wizzing around a metre or so behind the rudder, but that's another story)

+x

 

Simon Currin - 16 Feb 2024

A great real-world review. Thank you.

A few comments.
1. Did you consider a hydrogenerator? We thought about it for the Pacific but eventually decided we couldn’t justify the expense.

2. LiFePO has made a huge difference to our cruising when compared to our previous AGM’s. Don’t underestimate the advantages.

3. Agree about modern solar and wish we had added rail mounts to our similarly sized boat.

4. Less impressed with our wind generator but it may just be too old and inefficient..

5. We do have a diesel generator which made things much easier in the high latitude legs of our trip where solar is not much help.

6. Not keen on carrying petrol to feed a petrol generator having abandoned petrol outboards in favour of electric 12 years ago.

Thanks for sharing your thoughts.

Simon

+x

 

Dietmar.Segner - 15 Feb 2024

On our monohull boat we chose an approach to comfortable bluewater sailing without a generator. In the attached PDF we outline our design specifications and the experience of several years of sailing and living on the boat.

Hi Simon and Dietmar,
In your essay solar panels are mounted on lifelines/stanchions and Simon talks of regretting not doing so. I wrote the below a while back for another venue and include it here for readers to have alternative thoughts on solar panel mounting and “stuff on deck” in general.
My best, Dick Stevenson, s/v Alchemy
“Stuff” on Deck
Hi all,
There is a continual battle for most of us to not overload our boat: not doing so requires discipline and often some degree of deprivation (saying “no” to some desired something-or-other). Usually overloading just results in a hit to boat performance, difficult access to certain areas and to living with clutter. Sometimes “stuff” contributes to the crew operating safely and sometimes it can contribute to jeopardizing the integrity of the boat. The following are my descriptions of ways that “stuff” on deck may have serious repercussions that are not immediately apparent.
My arguments are directed for boats that will go offshore as boat motion and vulnerability to water on deck is greatest there, but, I believe, is applicable to all vessels wherever they wander.
In the following, I wish to make a case that gear attached to lifelines and stanchions is generally not wise or in the interests of the boat and is sometimes dangerous. This gear includes, but is not limited to, solar panels, jerry cans, kayaks and paddle/surfboards etc.
At the least immediately problematic, but perhaps the most insidious, look to your stanchions and lifelines. Stanchion deck fittings are not designed for (or installed to tolerate) the rhythmic back and forth tug/stresses of solar panels hung high, or heavy jerry cans, for example, pulling on them with every wave (or the rhythmic continuous pounding inflicted when sailing hard to wind). These repeated stresses lead to leaks in the stanchion bases (if your stanchion bases are leaking, look to whether there has been gear attached) or stress fractures (look at the welds down low). More dangerous is the leak that does not become apparent below decks (giving a warning) but may be saturating your deck core, especially problematic if the core is balsa. And these leaks can go long periods unobserved resulting in much damage and expense.
Pushpits are likely better attached to the deck and often are usually of cross-supported rigid tubing rather than wire. It therefore seems reasonable to have a horseshoe and a Lifesling and/or a MOM attached, and perhaps also a well-designed well-supported deck-stepped wind generator. But think of the forces accrued from a full enclosure whose support comes from the pushpit structure. Imagine further the forces beating to wind in swell or a sideways wind coupled with some big wave. These are unusual events, but far from unheard of and statistically likely with enough miles under your keel.
Finally, gear on deck is often a danger to moving around easily and safely, to footing and to working the boat. And your deck can become skating-rink slippery if a jerry can leaks a bit of diesel through heat expansion in the sun or otherwise.
The more dramatic examples of the folly of having “stuff” attached to lifelines and stanchions occurs when your boat falls off a wave or gets slammed by the occasional really large wave. The forces can be enormous and are hard to imagine ahead of time. (For those who have never been in a sailboat who has fallen off of a wave or gotten slammed by big one: think enormous blow, one that takes your breath away and causes you to worry about your fillings: an enormous belly-flop). These “wave” events are no longer rhythmic events that the ocean is always subjecting us to, but rather shock loads. And these shock loads increase impressively with the amount of surface area and weight. Jerry cans, with their weight, are hard on stanchions/lifelines for the rhythmic loads induced, but actually present a fairly small surface area. But many are supported by a wide board going from stanchion to stanchion: an invitation to take out the lifelines on the whole side of a boat. It is the paddleboards and kayaks which really excel in presenting a large target for waves or forces of the water that slam into the boat when falling off a wave. And perhaps most vulnerable to causing damage are solar panels which are usually mounted high on the lifelines/stanchion and subsequently exert the most leverage on the lifeline/stanchion combination.
No life/stanchion system is designed for these kinds of forces and few attachments to the deck will endure these forces (much of what is said above also applies to using handholds as tie-down spots as the ties and the stuff they are securing frequently make the handholds difficult to use as handholds).
Falling off a wave is impressively jarring, but the most dramatic and potentially damaging is a knockdown or a roll over. A knockdown will likely not cause exterior damage to a well set-up offshore boat. Add gear to the lifelines/stanchions and you are looking at the possibility of significant damage. Bent stanchions are probably a given, but holes from loosened or pulled out stanchion bases are likely and down-flooding could occur. (And do not under-estimate the danger to the crew attempting to respond to these problems: problems often lead to injury.)
Often, little on deck will survive a rollover. The forces are just too great. Possibly the greatest danger is the loss of one’s liferaft: many installations are far too flimsy and not through-bolted with backing plates. (If you did not install your raft: do you know for sure how it was installed?) I know of boats surviving a rollover only to find everything gone: even the wooden grabrails were gone that had been used to tie down gear leaving only the bolts protruding.
The damage to boat is what was focused on above, but in the boisterous conditions where the above events often occur, the danger to crew trying to deal with the problems arising from gear on deck that causes damage or become unsecured is a very real and scary possibility. When things are tumultuous, one wants to hunker down and not worry about the boat.
The forces on boats that fall off a wave or getting slammed by the occasionally really large wave can be enormous and hard to imagine ahead of time. Any misc. gear attached to the lifelines/stanchions is problematic. Stanchions are vulnerable to being ripped right out of the deck leaving holes for water to enter the boat. More likely, they become mangled and leave a dangerous deck to work on. (As a thought experiment, look at the exposed surface area of the picture of 4 diesel jerry cans secured to two stanchions along a long board. Firstly, notice the marked decrease in foot space for secure footing next to the chainplates. Next, imagine the forces on stanchions and their bases as 140 pounds of 4 full diesel cans rhythmically attempt to peel the bases off the deck when heeled 15 degrees and bouncing wave to wave. And finally think of the forces on the 4 jerry cans hit broadside by a wave and transferring those forces to two small deck fittings.)
Jerry cans are not alone: many solar panels installations invite problems especially as they are often secured high up where they have great leverage. Bicycles, kayaks, fender boards, and spray curtains are also frequently problematic (my spray curtains are attached with light bungie cord so they stretch/break away well before any stress/damage to the stanchions/lifelines), etc. Lifelines and the stanchions which support them are designed for crew safety, not as convenient tie off points. (If in doubt as to my assertions, please check with Naval Architects, engineers, and/or boat builders.)
Bottom line, I consider gear stored attached to lifelines/stanchions to be a safety issue to the boat, and sometimes to crew. Many with gear on deck will go years without mishap, but, like so many decisions regarding safety on the boat, it is best to plan for a scenario which keeps you and your vessel safe when, if you put enough miles under your keel, the statistically inevitable happens. I would suggest re-thinking all gear attached to lifelines/stanchions (or stern pushpit or handrails) with the intention of freeing this area from potential damage to the boat and for the safe operation of the boat by the crew.
My best, Dick Stevenson, s/v Alchemy

+x

 

Dick - 22 Feb 2024

+x

 

Simon Currin - 16 Feb 2024

A great real-world review. Thank you.

A few comments.
1. Did you consider a hydrogenerator? We thought about it for the Pacific but eventually decided we couldn’t justify the expense.

2. LiFePO has made a huge difference to our cruising when compared to our previous AGM’s. Don’t underestimate the advantages.

3. Agree about modern solar and wish we had added rail mounts to our similarly sized boat.

4. Less impressed with our wind generator but it may just be too old and inefficient..

5. We do have a diesel generator which made things much easier in the high latitude legs of our trip where solar is not much help.

6. Not keen on carrying petrol to feed a petrol generator having abandoned petrol outboards in favour of electric 12 years ago.

Thanks for sharing your thoughts.

Simon

+x

 

Dietmar.Segner - 15 Feb 2024

On our monohull boat we chose an approach to comfortable bluewater sailing without a generator. In the attached PDF we outline our design specifications and the experience of several years of sailing and living on the boat.

Hi Simon and Dietmar,
In your essay solar panels are mounted on lifelines/stanchions and Simon talks of regretting not doing so. I wrote the below a while back for another venue and include it here for readers to have alternative thoughts on solar panel mounting and “stuff on deck” in general.
My best, Dick Stevenson, s/v Alchemy
“Stuff” on Deck
Hi all,
There is a continual battle for most of us to not overload our boat: not doing so requires discipline and often some degree of deprivation (saying “no” to some desired something-or-other). Usually overloading just results in a hit to boat performance, difficult access to certain areas and to living with clutter. Sometimes “stuff” contributes to the crew operating safely and sometimes it can contribute to jeopardizing the integrity of the boat. The following are my descriptions of ways that “stuff” on deck may have serious repercussions that are not immediately apparent.
My arguments are directed for boats that will go offshore as boat motion and vulnerability to water on deck is greatest there, but, I believe, is applicable to all vessels wherever they wander.
In the following, I wish to make a case that gear attached to lifelines and stanchions is generally not wise or in the interests of the boat and is sometimes dangerous. This gear includes, but is not limited to, solar panels, jerry cans, kayaks and paddle/surfboards etc.
At the least immediately problematic, but perhaps the most insidious, look to your stanchions and lifelines. Stanchion deck fittings are not designed for (or installed to tolerate) the rhythmic back and forth tug/stresses of solar panels hung high, or heavy jerry cans, for example, pulling on them with every wave (or the rhythmic continuous pounding inflicted when sailing hard to wind). These repeated stresses lead to leaks in the stanchion bases (if your stanchion bases are leaking, look to whether there has been gear attached) or stress fractures (look at the welds down low). More dangerous is the leak that does not become apparent below decks (giving a warning) but may be saturating your deck core, especially problematic if the core is balsa. And these leaks can go long periods unobserved resulting in much damage and expense.
Pushpits are likely better attached to the deck and often are usually of cross-supported rigid tubing rather than wire. It therefore seems reasonable to have a horseshoe and a Lifesling and/or a MOM attached, and perhaps also a well-designed well-supported deck-stepped wind generator. But think of the forces accrued from a full enclosure whose support comes from the pushpit structure. Imagine further the forces beating to wind in swell or a sideways wind coupled with some big wave. These are unusual events, but far from unheard of and statistically likely with enough miles under your keel.
Finally, gear on deck is often a danger to moving around easily and safely, to footing and to working the boat. And your deck can become skating-rink slippery if a jerry can leaks a bit of diesel through heat expansion in the sun or otherwise.
The more dramatic examples of the folly of having “stuff” attached to lifelines and stanchions occurs when your boat falls off a wave or gets slammed by the occasional really large wave. The forces can be enormous and are hard to imagine ahead of time. (For those who have never been in a sailboat who has fallen off of a wave or gotten slammed by big one: think enormous blow, one that takes your breath away and causes you to worry about your fillings: an enormous belly-flop). These “wave” events are no longer rhythmic events that the ocean is always subjecting us to, but rather shock loads. And these shock loads increase impressively with the amount of surface area and weight. Jerry cans, with their weight, are hard on stanchions/lifelines for the rhythmic loads induced, but actually present a fairly small surface area. But many are supported by a wide board going from stanchion to stanchion: an invitation to take out the lifelines on the whole side of a boat. It is the paddleboards and kayaks which really excel in presenting a large target for waves or forces of the water that slam into the boat when falling off a wave. And perhaps most vulnerable to causing damage are solar panels which are usually mounted high on the lifelines/stanchion and subsequently exert the most leverage on the lifeline/stanchion combination.
No life/stanchion system is designed for these kinds of forces and few attachments to the deck will endure these forces (much of what is said above also applies to using handholds as tie-down spots as the ties and the stuff they are securing frequently make the handholds difficult to use as handholds).
Falling off a wave is impressively jarring, but the most dramatic and potentially damaging is a knockdown or a roll over. A knockdown will likely not cause exterior damage to a well set-up offshore boat. Add gear to the lifelines/stanchions and you are looking at the possibility of significant damage. Bent stanchions are probably a given, but holes from loosened or pulled out stanchion bases are likely and down-flooding could occur. (And do not under-estimate the danger to the crew attempting to respond to these problems: problems often lead to injury.)
Often, little on deck will survive a rollover. The forces are just too great. Possibly the greatest danger is the loss of one’s liferaft: many installations are far too flimsy and not through-bolted with backing plates. (If you did not install your raft: do you know for sure how it was installed?) I know of boats surviving a rollover only to find everything gone: even the wooden grabrails were gone that had been used to tie down gear leaving only the bolts protruding.
The damage to boat is what was focused on above, but in the boisterous conditions where the above events often occur, the danger to crew trying to deal with the problems arising from gear on deck that causes damage or become unsecured is a very real and scary possibility. When things are tumultuous, one wants to hunker down and not worry about the boat.
The forces on boats that fall off a wave or getting slammed by the occasionally really large wave can be enormous and hard to imagine ahead of time. Any misc. gear attached to the lifelines/stanchions is problematic. Stanchions are vulnerable to being ripped right out of the deck leaving holes for water to enter the boat. More likely, they become mangled and leave a dangerous deck to work on. (As a thought experiment, look at the exposed surface area of the picture of 4 diesel jerry cans secured to two stanchions along a long board. Firstly, notice the marked decrease in foot space for secure footing next to the chainplates. Next, imagine the forces on stanchions and their bases as 140 pounds of 4 full diesel cans rhythmically attempt to peel the bases off the deck when heeled 15 degrees and bouncing wave to wave. And finally think of the forces on the 4 jerry cans hit broadside by a wave and transferring those forces to two small deck fittings.)
Jerry cans are not alone: many solar panels installations invite problems especially as they are often secured high up where they have great leverage. Bicycles, kayaks, fender boards, and spray curtains are also frequently problematic (my spray curtains are attached with light bungie cord so they stretch/break away well before any stress/damage to the stanchions/lifelines), etc. Lifelines and the stanchions which support them are designed for crew safety, not as convenient tie off points. (If in doubt as to my assertions, please check with Naval Architects, engineers, and/or boat builders.)
Bottom line, I consider gear stored attached to lifelines/stanchions to be a safety issue to the boat, and sometimes to crew. Many with gear on deck will go years without mishap, but, like so many decisions regarding safety on the boat, it is best to plan for a scenario which keeps you and your vessel safe when, if you put enough miles under your keel, the statistically inevitable happens. I would suggest re-thinking all gear attached to lifelines/stanchions (or stern pushpit or handrails) with the intention of freeing this area from potential damage to the boat and for the safe operation of the boat by the crew.
My best, Dick Stevenson, s/v Alchemy

Not all boats are built with stanchions that cant take any load. our solar panels are located on the guardrails. 2x180w panels on each side of the boat. The toerail on our boat is a substantial aluminium extrusion, bolted through the solid glass margin of an otherwise Airex cored deck. The M8 bolts are located every 100mm. The toerail is the mounting point for the stanchion bases. These stanchion bases bolt through the toerail not the deck. 3 bolts per stanchion base. 
The stanchions are solid 1 inch thick aluminium.
The reality of carrying anything on deck in a storm is that it can be lost. Liferafts, danbouy, solar panels, sprayhood, fuel cans, etc.
The tendency for cruisers to install larger and larger solar panels on arches is not without risk. In storm conditions, the surface area of large panels is considerable. They are just as likely to be at risk of being ripped off as the boat leans hard over and exposes the solar panels at an angle similar to your sails. Also consider the weight of large panels so high up impacting on the righting moment.
It's not a perfect world but we are more than happy with rail mounted tiltable panels and after 6 Atlantic crossing with no mishaps, we will continue to use them this way

Further to the previous comment I would add that if the pushpit isn‘t able to carry the loads of the solar panels on the rail the main concern is not the loss of panels but rather the loss of life as the rail and/or pushpit is not up to its task of preventing people being swept overboard. On an aluminum boat like ours the toerail is topped by a massive 10mm aluminum plate to which stanchion bases are welded. Absolutely stable. And stanchions or pushpits can be specified (wall thickness) so they are up to the task. Similarly, as described above, GRP boats can be constructed sensibly, but it is unlikely that every production boat is automatically up to the task.
dietmar 

+x

 

Dietmar.Segner - 10 Jul 2024

Further to the previous comment I would add that if the pushpit isn‘t able to carry the loads of the solar panels on the rail the main concern is not the loss of panels but rather the loss of life as the rail and/or pushpit is not up to its task of preventing people being swept overboard. On an aluminum boat like ours the toerail is topped by a massive 10mm aluminum plate to which stanchion bases are welded. Absolutely stable. And stanchions or pushpits can be specified (wall thickness) so they are up to the task. Similarly, as described above, GRP boats can be constructed sensibly, but it is unlikely that every production boat is automatically up to the task.
dietmar 

I concur. Building a boat that is up to the job makes all the difference 

+x

 

Wild.Bird - 10 Jul 2024

+x

 

Dietmar.Segner - 10 Jul 2024

Further to the previous comment I would add that if the pushpit isn‘t able to carry the loads of the solar panels on the rail the main concern is not the loss of panels but rather the loss of life as the rail and/or pushpit is not up to its task of preventing people being swept overboard. On an aluminum boat like ours the toerail is topped by a massive 10mm aluminum plate to which stanchion bases are welded. Absolutely stable. And stanchions or pushpits can be specified (wall thickness) so they are up to the task. Similarly, as described above, GRP boats can be constructed sensibly, but it is unlikely that every production boat is automatically up to the task.
dietmar 

I concur. Building a boat that is up to the job makes all the difference 

Hi Dietmar,
I agree, freedom from injury, to persons first and to the boat second is of primary concern.
In general, I believe it is possible to build/design/engineer stanchions, when used as tie-downs for solar panels, jerry jugs, kayaks and the like, that would endure the impact force of water hitting them when the boat falls off a wave or is otherwise slammed. But how many boats go that far. I was writing for the vast majority of the boats I see in the ports passage makers hang out. Better, I think, for most boats to just resist using their stanchions in this manner. Cluttering the deck is just plain too much of a hazard potential in a myriad of ways, as my first comment in this stream observed.
My best, Dick Stevenson, s/v Alchemy

+x

 

Wild.Bird - 10 Jul 2024

+x

 

Dick - 22 Feb 2024

+x

 

Simon Currin - 16 Feb 2024

A great real-world review. Thank you.

A few comments.
1. Did you consider a hydrogenerator? We thought about it for the Pacific but eventually decided we couldn’t justify the expense.

2. LiFePO has made a huge difference to our cruising when compared to our previous AGM’s. Don’t underestimate the advantages.

3. Agree about modern solar and wish we had added rail mounts to our similarly sized boat.

4. Less impressed with our wind generator but it may just be too old and inefficient..

5. We do have a diesel generator which made things much easier in the high latitude legs of our trip where solar is not much help.

6. Not keen on carrying petrol to feed a petrol generator having abandoned petrol outboards in favour of electric 12 years ago.

Thanks for sharing your thoughts.

Simon

+x

 

Dietmar.Segner - 15 Feb 2024

On our monohull boat we chose an approach to comfortable bluewater sailing without a generator. In the attached PDF we outline our design specifications and the experience of several years of sailing and living on the boat.

Hi Simon and Dietmar,
In your essay solar panels are mounted on lifelines/stanchions and Simon talks of regretting not doing so. I wrote the below a while back for another venue and include it here for readers to have alternative thoughts on solar panel mounting and “stuff on deck” in general.
My best, Dick Stevenson, s/v Alchemy
“Stuff” on Deck
Hi all,
There is a continual battle for most of us to not overload our boat: not doing so requires discipline and often some degree of deprivation (saying “no” to some desired something-or-other). Usually overloading just results in a hit to boat performance, difficult access to certain areas and to living with clutter. Sometimes “stuff” contributes to the crew operating safely and sometimes it can contribute to jeopardizing the integrity of the boat. The following are my descriptions of ways that “stuff” on deck may have serious repercussions that are not immediately apparent.
My arguments are directed for boats that will go offshore as boat motion and vulnerability to water on deck is greatest there, but, I believe, is applicable to all vessels wherever they wander.
In the following, I wish to make a case that gear attached to lifelines and stanchions is generally not wise or in the interests of the boat and is sometimes dangerous. This gear includes, but is not limited to, solar panels, jerry cans, kayaks and paddle/surfboards etc.
At the least immediately problematic, but perhaps the most insidious, look to your stanchions and lifelines. Stanchion deck fittings are not designed for (or installed to tolerate) the rhythmic back and forth tug/stresses of solar panels hung high, or heavy jerry cans, for example, pulling on them with every wave (or the rhythmic continuous pounding inflicted when sailing hard to wind). These repeated stresses lead to leaks in the stanchion bases (if your stanchion bases are leaking, look to whether there has been gear attached) or stress fractures (look at the welds down low). More dangerous is the leak that does not become apparent below decks (giving a warning) but may be saturating your deck core, especially problematic if the core is balsa. And these leaks can go long periods unobserved resulting in much damage and expense.
Pushpits are likely better attached to the deck and often are usually of cross-supported rigid tubing rather than wire. It therefore seems reasonable to have a horseshoe and a Lifesling and/or a MOM attached, and perhaps also a well-designed well-supported deck-stepped wind generator. But think of the forces accrued from a full enclosure whose support comes from the pushpit structure. Imagine further the forces beating to wind in swell or a sideways wind coupled with some big wave. These are unusual events, but far from unheard of and statistically likely with enough miles under your keel.
Finally, gear on deck is often a danger to moving around easily and safely, to footing and to working the boat. And your deck can become skating-rink slippery if a jerry can leaks a bit of diesel through heat expansion in the sun or otherwise.
The more dramatic examples of the folly of having “stuff” attached to lifelines and stanchions occurs when your boat falls off a wave or gets slammed by the occasional really large wave. The forces can be enormous and are hard to imagine ahead of time. (For those who have never been in a sailboat who has fallen off of a wave or gotten slammed by big one: think enormous blow, one that takes your breath away and causes you to worry about your fillings: an enormous belly-flop). These “wave” events are no longer rhythmic events that the ocean is always subjecting us to, but rather shock loads. And these shock loads increase impressively with the amount of surface area and weight. Jerry cans, with their weight, are hard on stanchions/lifelines for the rhythmic loads induced, but actually present a fairly small surface area. But many are supported by a wide board going from stanchion to stanchion: an invitation to take out the lifelines on the whole side of a boat. It is the paddleboards and kayaks which really excel in presenting a large target for waves or forces of the water that slam into the boat when falling off a wave. And perhaps most vulnerable to causing damage are solar panels which are usually mounted high on the lifelines/stanchion and subsequently exert the most leverage on the lifeline/stanchion combination.
No life/stanchion system is designed for these kinds of forces and few attachments to the deck will endure these forces (much of what is said above also applies to using handholds as tie-down spots as the ties and the stuff they are securing frequently make the handholds difficult to use as handholds).
Falling off a wave is impressively jarring, but the most dramatic and potentially damaging is a knockdown or a roll over. A knockdown will likely not cause exterior damage to a well set-up offshore boat. Add gear to the lifelines/stanchions and you are looking at the possibility of significant damage. Bent stanchions are probably a given, but holes from loosened or pulled out stanchion bases are likely and down-flooding could occur. (And do not under-estimate the danger to the crew attempting to respond to these problems: problems often lead to injury.)
Often, little on deck will survive a rollover. The forces are just too great. Possibly the greatest danger is the loss of one’s liferaft: many installations are far too flimsy and not through-bolted with backing plates. (If you did not install your raft: do you know for sure how it was installed?) I know of boats surviving a rollover only to find everything gone: even the wooden grabrails were gone that had been used to tie down gear leaving only the bolts protruding.
The damage to boat is what was focused on above, but in the boisterous conditions where the above events often occur, the danger to crew trying to deal with the problems arising from gear on deck that causes damage or become unsecured is a very real and scary possibility. When things are tumultuous, one wants to hunker down and not worry about the boat.
The forces on boats that fall off a wave or getting slammed by the occasionally really large wave can be enormous and hard to imagine ahead of time. Any misc. gear attached to the lifelines/stanchions is problematic. Stanchions are vulnerable to being ripped right out of the deck leaving holes for water to enter the boat. More likely, they become mangled and leave a dangerous deck to work on. (As a thought experiment, look at the exposed surface area of the picture of 4 diesel jerry cans secured to two stanchions along a long board. Firstly, notice the marked decrease in foot space for secure footing next to the chainplates. Next, imagine the forces on stanchions and their bases as 140 pounds of 4 full diesel cans rhythmically attempt to peel the bases off the deck when heeled 15 degrees and bouncing wave to wave. And finally think of the forces on the 4 jerry cans hit broadside by a wave and transferring those forces to two small deck fittings.)
Jerry cans are not alone: many solar panels installations invite problems especially as they are often secured high up where they have great leverage. Bicycles, kayaks, fender boards, and spray curtains are also frequently problematic (my spray curtains are attached with light bungie cord so they stretch/break away well before any stress/damage to the stanchions/lifelines), etc. Lifelines and the stanchions which support them are designed for crew safety, not as convenient tie off points. (If in doubt as to my assertions, please check with Naval Architects, engineers, and/or boat builders.)
Bottom line, I consider gear stored attached to lifelines/stanchions to be a safety issue to the boat, and sometimes to crew. Many with gear on deck will go years without mishap, but, like so many decisions regarding safety on the boat, it is best to plan for a scenario which keeps you and your vessel safe when, if you put enough miles under your keel, the statistically inevitable happens. I would suggest re-thinking all gear attached to lifelines/stanchions (or stern pushpit or handrails) with the intention of freeing this area from potential damage to the boat and for the safe operation of the boat by the crew.
My best, Dick Stevenson, s/v Alchemy

Not all boats are built with stanchions that cant take any load. our solar panels are located on the guardrails. 2x180w panels on each side of the boat. The toerail on our boat is a substantial aluminium extrusion, bolted through the solid glass margin of an otherwise Airex cored deck. The M8 bolts are located every 100mm. The toerail is the mounting point for the stanchion bases. These stanchion bases bolt through the toerail not the deck. 3 bolts per stanchion base. 
The stanchions are solid 1 inch thick aluminium.
The reality of carrying anything on deck in a storm is that it can be lost. Liferafts, danbouy, solar panels, sprayhood, fuel cans, etc.
The tendency for cruisers to install larger and larger solar panels on arches is not without risk. In storm conditions, the surface area of large panels is considerable. They are just as likely to be at risk of being ripped off as the boat leans hard over and exposes the solar panels at an angle similar to your sails. Also consider the weight of large panels so high up impacting on the righting moment.
It's not a perfect world but we are more than happy with rail mounted tiltable panels and after 6 Atlantic crossing with no mishaps, we will continue to use them this way

Hi Wild Bird,
Agree completely:
The tendency for cruisers to install larger and larger solar panels on arches is not without risk. In storm conditions, the surface area of large panels is considerable. They are just as likely to be at risk of being ripped off as the boat leans hard over and exposes the solar panels at an angle similar to your sails
The reality of carrying anything on deck in a storm is that it can be lost. Liferafts, danbouy, solar panels, sprayhood, fuel cans, etc.
Also consider the weight of large panels so high up impacting on the righting moment.
Perhaps more of import on the last copied observation is the adverse impact of adding significant weight at the very end of the boat: the very worst place for adding weight.
And, I believe that your observation that a large solar array on the stern at an angle similar to the sails is a consideration little considered and quite important for upwind sailing balance, especially if wishing to claw away from a lee shore in heavy winds.
Not sure there are stanchions on any recreational sailboat that can stand up to the impact of significant water hitting a large piece of something tied to them: solar panels, jerry cans, paddleboard etc.
Say more about your solid aluminum stanchions: it has always been my understanding that a tube with sufficient wall thickness was far stiffer/stronger than solid. And how do they differ in performance to the usual stainless-steel tubular stanchions.
My best, Dick