Looks like a pretty standard dock, albeit it one in much better shape that most floating platforms, which I suppose speaks to the utility of the composite materials in harsh marine environments. So while the maintenance costs are reduced and the lifecycles might be longer, does the choice of composite materials over metal up the cost significantly?
Beth, the pontoon project is a custom job, so it's not surprising that the partners didn't mention specific cost details. Since, as we stated, the composite practically eliminates maintenance and doubles the design life, I suspect the overall cost of ownership is lower.
Ann, this is yet another interesting use of composites. I wonder, though about the environmental impact. In discussing the ballast, the EFC, it seems that the builders were paying attention to the environmental impact of their structure. That is good. The EFC uses byproduct of other industrial processes, thus extending the use of the raw materials. I have seen the amount of fly-ash produced by a small coal fired plant. Usually it is burried in the coal mine. Now, I expect that this structure will have a lower life cycle cost becuase of the lower maintenance. As Beth asked, what about the initial cost (is it comparable)? The other environmental question is, what happens to the structure when it is finally retired. Can the materials be recycled? One thing about steel is that it can, indefinately. Once refined, it is indistinguishable from the original (think steel mini-mills). Composites, on the other hand, can generally only be recycled into lower level forms. That is my assumption. Do you have any information on that aspect?
naperlou, good questions. There are some efforts underway to develop recycling methods for composites, most notably Boeing: http://www.designnews.com/document.asp?doc_id=235280 That said, I'm not familiar with the situation in Australia, or whether the marina industry has thought of that problem yet, since the materials last so long.
I think this is a bad use of composite. I have not run the numbers yet. But I live in Florida. Lots of storms right? Guess what? There are floating docks here in Florida from the 70's and they were cheaply made with yours truly "Concrete". They are big, chunky, heavy, durable, and cheap. If they break they sink. Keep in mind floating things in a hurricane can be problematic considering they can be picked up and flung at something so a good bit of mass is always a plus. Yes concrete blocks underwater could become potential debris for structures downstream too it's hard to gauge what's best. However it is know that cheap always beats good looking. I will have to go with concrete on this one... At least until data point the other direction.
ervin, as the article states, the pontoon is made of composites, not concrete, and is built for cyclone conditions. Lots of sub-par construction occurred in the US in the 1970s. Since then, the building codes in many regions of the US have changed, due in part to earthquake and hurricane-caused disasters. I suspect something similar has occurred in Australia.
A serious lack of details. The composite seems to be the beams, rails and calling them maintaince free is a joke. The coating can and will be damaged a lot and likely the composite part too from boats ramming it, etc.
How do they pultrude Vinyl ester resin which normally takes many minutes to go from liquid to solid. Some engineering details would be nice.
Recycling is easy, just heat to 1000F and use the gas made from the resin. Recycling FG just gives you sand so not worth it.
Racking in a cyclone is likely to break at the bolt holes/point loads much more easy than alum would.
What is the 'concrete' actually used for?
What are the floats, decks made of? Is it the larger rectangles under the deck beams? If so not much floatation.
Leaving boats at a dock in a cyclone/hurricane is very problematic and most docks in Fla say in a hurricane you must move them away to keep from damaging the docks or sinking of the boats from pounding into the docks. BTDT many times. Made a lot of money repairing same afterward.
I take my boats to canals or mangroves and tie them with long lines in the middle away from anything hard. I've been though a lot of them caring for my boats and others professionally. You need 15-50' from anything hard depending on tidal surge, range and bost size.
A well done concrete dock floats will last centuries as they get stronger with age. Ask anyone trying to get rid of a concrete ship. The only way is to sink it. For a floating island the only viable material is concrete.
The article seems to be better performance through advertising.
Washington state has three rather large concrete pontoon bridges (I-90, 520, and Hood Canal). One's being replaced with another concrete pontoon bridge right now. It's being replaced because it doesn't provide enough capacity.
The skills used to build these bridges can then be put to use on any future construction project, be it bridge, building, or dam.
As for lower carbon footprint of the concrete mentioned in the article, it seems laughable compared to the amount of carbon put into the atmosphere by the current Colorado forest fires.
I can see that these are good looking floating docks, and I suppose that they can be used for hydrofoil boats quite well, but I see no way that they could offer much protection to a boat in a typhoon, or any big storm. Like the comments say, objects bang togather in storms, and damage is done by that banging.
Or is the plan that these floating docks are big and heavy enough to shield the catamaron boats? That would be interesting indeed. I would like to see pictures of that.
The alternative cement material used for ballast is an interesting concept, and I am not aware that it is used in this part of the country, (southeast Michigan), so it would be a good topic for a writeup some time in the future.
The pontoon itself is built for cyclone conditions. That doesn't necessarily mean it's built to protect boats during a cyclone. Having seen the $25 million-plus devastation of the harbor here in nearby Santa Cruz, CA after the Tohoku tsunami last year, I'd be surprised if any structure could protect boats under those conditions. Anyone know if there is one that can?
As they say Ann, that depends. And not just on the dock but the things around it.
It depends on the water they are in and how protected it is, how bad the storm is, how they are tied up, how much other things can get blown into them from around the water, how the other boats are secured, how much tide, surge there is, etc.
Thus why I seek a closed waterway like canals, mangroves, etc not too wide and able to put lines across it to prevent other boats that break loose from getting to mine, enough line length to allow for tidal surge without pulling the dock, piling up, out, a dock secured well enough it won't come loose and crush the boats, etc.
Thanks, Jerry. Those are the same variables that were discussed here after the Santa Cruz Harbor damage. The shape of the harbor and the way the tsunami waves traveled into it apparently made it more vulnerable than other, nearby harbors. But I also heard a lot of people saying that the boats either shouldn't have been tied up there, or should have been tied differently. Of course, this is all hindsight, and no one realized what was coming in time to do anything about it.
I live in Fla and I knew about the Tsunami danger to the whole west coast. So they should have as it wasn't a secert. Likely they willfully ignored it
The Hawaii damage from it should have been a clue to them if nothing else.
A real problem for Cal is there are so many boats and so few slips many times they are stacked 2-5+ deep and the only safe thing to do is head out to sea for most. The time of arrival was known well in advance to the hour.
The shape of the harbor is extremely important but again that was well known too by anyone who asked or just looked at the charts they should have had on every boat. As was the direction it was coming from. They were just making excuses for being too lazy to care for their boats and deflecting blame.
I didn't get the impression that it was willful ignoring of the dangers: not at all. People here were devastated at their losses. I don't think people realized how much damage could be done, and which harbors would have worse damage then others due to different shapes. I learned about that after the fact, primarily through local news outlets, and I suspect others did, too. There was a surprisingly small amount of fingerpointing making those types of accusations. Our situation is quite different from the East Coast with its hurricanes and cyclones, meaning, we don't exactly get tsunamis every day here. This was quite unusual. That said, there was a lot of discussion after the tsunami about how to do things differently, but the shape of the harbor apparently is a big factor.
Ann, nature doesn't care and anyone on the water had better understand that and what is needed or what happened will again. If one doesn't learn the problems they will face on the water will lead to loss of boat and even lives. It's the captain's responsability by law.
The danger was on the news day/s in advance which should have been heeded by anyone with a boat on the whole west coast. Didn't they see what happened in Hawaii?
I knew it here in Fla so it's rather lame to say those in Cal were not informed. There have been programs on just this danger and how many times it has happened before. So yes it was willful ignoring.
If a big earthquake hits anywhere in the Pacific one should keep track of it if one is on or even near the water.
Same thing on the east coast where when one comes, and it will, will take out far more like when the Azores underwater cliffs fell before Columbus came and wiped out much of the lower lying land just like Indoneisa had more recently.
People on the west coast knew a tsunami was coming, but we didn't know how it would affect a given harbor in a given way. I was reading the local newspapers, news sites, etc,. and no one was clear on this until after the fact, probably because nothing like that had happened here in living memory: the scale was totally different, and the quantitative differences produced qualitative differences. On this coast, living memory/recorded history/the history of taking modern measurements, etc. is a lot shorter than on the east coast. There was some talk of moving boats out of the harbor, but not enough warning time for a concerted, organized effort to figure out and complete that task.
Ann R Thryft; There is a difference between 'boaters' and experienced 'sailors'. I have met many boaters who mainly use the boat to drink (alcohol) while it is tied up at the dock. Or raft together on a lake and party / drink. As mentioned in another post, there isn't enough space in many harbors to properly anchor boats to allow the range of movement to ride out the storm and not hit something that will damage them.
Glenn, I know what you mean. Santa Cruz Harbor has several actual experienced sailors, many of whom are fishermen. In fact, I'd bet that they're the majority. This isn't Marina del Ray: I've lived near that one, too, and it had way more boaters than sailors. From everything I read, the main problem wasn't only advance knowledge or even experience, but what you said--not enough room to properly anchor boats--plus not enough time to get them all out before the damage arrived.
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