Turning houses into boats...???

[Buzzook]

OK, be gentle, not an engineer. Only a gorblimey chippie, by trade...so understand nothing...much...but am aware that climate change effects are becoming more visible and more regular, leading to a greater than historic frequency of repeat inundations in riverine and coastal environments.

What I'd like to understand is whether or not it might be feasible to turn 'lightweight timber structures' like older-style timber framed, timber-clad dwellings, into 'houseboats' as a means of avoiding repetitive flood inundation (as per Lismore NSW in recent years).

As a boat owner, and marina user occasionally, I'm familiar with the modern 'marina construction' methodology of driven piles and floating pontoons.

Would it be possible to place similar driven piles (maybe vibration driven) around such dwellings, jack them up, add floatation chambers to the sub-structure (possibly even add a RHS steel sub-structure to prevent twisting), and attach 'rollers' at the pile attachment points, to enable such homes to simply *rise and fall* with the floodwaters..?

OK, so I know my thumbnail sketch is a massive over-simplification of what would need to occur to make this work but....could it work...??

My best guess on house mass is between 4-10 tonnes. So would 4000-10000L of buoyancy be enough to float that...??? Even if double that was necessary, a 1.0m X 1.0m X 10m rotomoulded floatation chamber would contain 10,000L, so two of them, either side of the dwelling...?? [This is wet thumb in the breeze guesswork, so probably hopelessly inadequate...]

I'm not even remotely close to being a mathematician, so cannot hazard more than a guess at whether this might even be possible, so am wondering if there are engineers here willing to respond - kindly - and without scoffing *too* loudly at my 'below the salt' hypothesis....????

It seems to me, from the $$$numbers various agencies have been floating about, that there is a LOT of expenditure on new, greenfields land, and new-built housing to 'replace' so-called flood-affected housing. Maybe $500-800K per dwelling. What might the 'cost per pile' be for, let's say, 500mm diameter 10m long R/C driven piles...?? Especially if, as seems to be the case, there could be a lot of 'ongoing work' in localised areas, enabling some degree of 'scale' to be factored in.

I'm wondering whether there is enough in that to interest a piling engineering firm to perhaps investigate the feasability of 'floating the boat' rather than removing the dwelling and destroying the existing community....??

I mean, thousands of homes along every river and coastline....with a successfully designed 'floatation system' potentially being a 'development condition' for future dwellings in flood-risk areas.....

There's certainly, I think, some potential there, if someone could work out a cost-effective 'system'...??

Now, I'll just don my flame-proof overalls, and duck behind this heatshield......

Anyone care to enlighten me? Politely? Tx in advance.

 

[TugboatEng]

No. First, there has been no observable sea level rise since the start of the industrial revolution. Most of the structures that existed before have become delapidated and then demolished. Any floatation systems would suffer the same fate before any structures experienced sea level rise. Even at Earth's highest ever rate of sea level rise, during which humans thrived and expanded their footprint, it was still only 1 inch per year.

The structures with enough value to be worth floating might be high-rise buildings and power plants but those would not be floatable for many other reasons including weight.

Why is the current generation of students so terrified or the idea of adaptation? Who did you wrong?

 

[GregLocock]

Actual numbers are that sea level rise is 3mm/y, or 1 ft per century. The tidal range (low low water to high high tide) where you live might be as little as 2 ft, or as much as 20 ft. Since the last Ice Age sea levels have risen by dozens of feet. As such worry warting about a foot in a hundred years seems a bit daft.

 

[LittleInch]

I saw this on a design house program recently.

The issue of the flexible connections to services was quite tricky.

This is more about flooding I think rather than sea level changes.

Amphibious House | Baca Architects

The UK’s first Amphibious House. A small island located on the River Thames, in south Buckinghamshire, is home to 15 houses. The houses, which were mostly built before the 1950s, are typically raised about 1 m off the ground on timber piles to protect them from flooding. At the time of...

www.baca.uk.com

 

[XR250]

No. First, there has been no observable sea level rise since the start of the industrial revolution.

My local beaches would beg to differ

 

[TugboatEng]

There is a product called cellular concrete which essentially creates buoyancy in less stable soils as an alternative to compaction. Perhaps that is what you're looking for?

XR, are you sure your beaches aren't experiencing erosion?

 

[GregLocock]

@XR250- the seismic plate that forms the USA is tipping, and local actions such as dredging, building cities, and groundwater extraction all affect local sea levels vastly more than the thermal expansion of seawater and melting ice. The mean sea level is measured relative to the average geoid, not tippy up/sinking bits of land.

 

[Buzzook]

Actual numbers are that sea level rise is 3mm/y, or 1 ft per century. The tidal range (low low water to high high tide) where you live might be as little as 2 ft, or as much as 20 ft. Since the last Ice Age sea levels have risen by dozens of feet. As such worry warting about a foot in a hundred years seems a bit daft.

If 3.4mm per decade was the ONLY concern it might be "worry warting". Unless of course you live in the PAcific rrregion on a coral atoll already becomig uninhabitable with only the so-far-measured 12-15cm since 1880.
But given COP targets are simpply NOT being met, it is more not less likely that the higher end targets of between 55 and 85cm is likely to be achieved by the end of this century, with further increase predicted (with less accuracy) into the next century or two. And these predictions do not include any 'as yet unknown' feedback loops that might cause faster glacial melting.

To put this into perpective, where I live, a Moderate flood is 5.8m AHD and a Major flood is 6.6m AHD. In other words, EVERY flood will become a Major flood, and so the inundations, damage and lack of insurance is going to get worse.

What I am attempting to address is mitigation of EXISTING flood levels and inundations, and looking for 'blue sky' propositions that **might** be feasible - with some good work by some seriously knowledgeable engineers.

Back in the sixties and seventies, many riverside communities had govt funding provided to raise homes one floor off the ground. This it is clear is not enough, and such homes are still being inundated. More often than was predicted in the sixties.

So do we simply take the "Obi-Wan position" and retreat to the higher ground..?? And so destroy towns and communities.....

Or do we make more of an effort to mitigate the effects of inundatoion and keep communities viable..?

 

[TugboatEng]

The flooding in Lismore is a result of rainfall. Perhaps you should investigate retention or diversion or the water during storms. Take a look at what Los Angeles did.

 

[GregLocock]

Better get on the phone to China, I'm sure they'll be interested.

Meanwhile "Using rich collections of Landsat imagery, this study analyses changes in land area on 221 atolls in the Indian and Pacific Oceans. Results show that, between 2000 and 2017, the total land area on these atolls has increased by 61.74 km2 (6.1 %) from 1007.60 km2 to 1069.35 km2." https://www.sciencedirect.com/science/article/abs/pii/S2213305421000059#:~:text=Using rich collections of Landsat,2 to 1069.35 km2.

So they are drowning while the atolls are getting bigger.Some of that increase is manmade, ie adaptation, the rest is natural, not surprising since atolls have survived the enormous increase in sea level since the last important bit of climate change.

As the AI says



I assume you get your 'science' from the ABC.

 

[TugboatEng]

One of the problems you're going to be faces with is the gradual rise and recession of water levels. There will be transitions where the house is not fully buoyancy and sits at odd angles. With little water under the house it's going to slam into the bottom with every wave or ripple. The water will be too deep for roads and too shallow for boats. Everyone will be trapped in their crooked and rattling homes.

So you see, there is a reason we divert you away from this idea. Far too often nowadays money is wasted on silly ideas instead of real solutions.

For example:

Have you seen the canals of Los Angeles? The city hardly gets any rain, 15 inches average a year. Yet the canal system is massive. The trouble is that they get all of their annual rain at once.

So I think the key here is that of you can divert and store the water with canals and reservoirs, then you can put houseboats on the reservoirs.

 

[TugboatEng]

Ok, if you want to make a house into a boat you're going to have to replace every screw and nail into wood with silicon bronze or monel.

 

[LittleInch]

Utter rubbish. Turning houses into "occasional pontoons' as per the ORIGINAL FUCKING POST, which you have still obviously neither read nor understood, does not require this.
I conclude you are a troll, and I will not respond to your posts in future. Good day to you!

I can see you're new and young, but this behaviour and language is not tolerated or accepted on this site. Please consider your posts and delete / edit as required.

If engineers cannot converse in a civil manner then no one can. you respond to comments with arguments and alternative opinions, not swearing and an aggressive tone. Tug has a certain errr style about some of his comments, but that's how it goes. He is a long standing member here.

 

[LionelHutz]

I conclude you are a troll, and I will not respond to your posts in future. Good day to you!

A self proclaimed troll, so yes have made the correct conclusion. Use the block user and you don't have to see any further BS from that user.

 

[XR250]

There is a product called cellular concrete which essentially creates buoyancy in less stable soils as an alternative to compaction. Perhaps that is what you're looking for?

XR, are you sure your beaches aren't experiencing erosion?

Erosion is occurring but they replenish it. High tide is basically going all the way to the dunes now and it used to not even come close.

 

[XR250]

@XR250- the seismic plate that forms the USA is tipping, and local actions such as dredging, building cities, and groundwater extraction all affect local sea levels vastly more than the thermal expansion of seawater and melting ice. The mean sea level is measured relative to the average geoid, not tippy up/sinking bits of land.

Since I have no idea what you are talking about, do you have a reference for this?

 

[Rputvin]

edit: just noticed OP was banned. oh well

 

[LittleInch]

Good. This thread started off quite reasonably, but somehow went south very fast.

 

[GregLocock]

@XR250 yes of course I have references.I suggest google will help you once you have well formed questions.

 

[SnTMan]

The problem just wanted an adequate application of OPM