Ok everyone, it's that time of the year again: time to talk about concrete

Thanks for your thoughtful reply. I haven't finished it, but I'm really glad that the post is continuing to garner attention. I haven't forgotten the project, and I'll go more into the lack of posts in a separate post.

I did want to address the cost point though, because I think you're absolutely right: $20k (US or Australian) isn't going to get greenlit by Mrs. Dsigned anytime soon. With that said I decided on a "proof of concept" design that is trying to be a poor man's version of a Laser Vortex or Hobie Bravo. A quick comment though: even a full size hull in UHPC and fiberglass mesh wouldn't be very expensive. Rigging, etc. would need to be sourced on the cheap, but fancy concrete isn't really that more than cheap concrete, and is still A LOT cheaper than marine plywood.

A final question: where in the Philippines are you? My family lived in Manila (Valley Golf, if you know where that is) for about 5 years, and Vietnam before that, so I'm familiar with the country to some extent. My dad always wanted to stick a windsurfer sail on one of the bankas and use it as cheap speed.

 

Update for those interested:

So, the baby concrete cat is on hiatus, not because of technical challenges, but because I got accepted to grad school for Philosophy and moved my family to a different state. I don't currently have a garage or any free time, so the boat is back on the backburner. It's been a while, so I'm not sure how much of my progress I got around to posting here, but if and when I have time (and if there's interest) I'll post how far I got before we moved. The last thing I think I sourced concrete wise was a 50ft roll of fiberglass mesh that I ordered from Home Depot (or something). I also tried my hand at making my own amorphous silicate flour (i.e. very finely ground clear glass bottles), which I was intending to put into a new concrete test panel.

 

Yeah, except replace "beams" with "sailing dinghy". I'm not sure I'm terribly concerned with resale value. If you're buying a boat and seriously thinking about resale value after you've been sailing it around for a decade or so, I think you've got some serious issues with your financial planning. Either it starts off worthless and ends up worthless, or it starts off expensive and depreciates like hell. What I am concerned with is barriers to entry (startup cost), cost of ownership, and effort going into upkeep. Frankly, fiberglass ticks two of those boxes really well, and buying used ticks the third. Unless you want something besides a vanilla sloop-rigged monohull. And frankly, I think there are some good reasons to want something besides a sloop rigged monohull. A conservatively rigged multi should (in theory) be safer, faster and more comfortable both in crossings and at anchor. But just about any production cat (or tri) from the past 20-30 years with reasonable accomodations is massive, crazy expensive, and designed to be a floating palace.

 

Hi - I've gone back to writing my book so the mind is a bit blank on the boat tangent of a few months ago. If you want some really good info on 'concrete' designs - check out all the info on the US national concrete canoe competition as their design and construction methods are fully documented in detail. Not much ferro in their canoe designs, mostly the high cost stuff. The basic idea I had for plastic floats, just didn't pass the reality test beyond flat water conditions, given I need something like a catamaran custom workboat/dive boat that can get out and in through surf but also with a low draft for crossing shoals. I'm living about 10 minutes walk from the Fields Ave tourist area so a long way from my ideal beach getaway in the Philippines - Pundaquit, San Antonio, Zambales. Maybe one day I might be able to move there and get back to a proof of concept smaller 'sailing cat' version to what I've got in mind before building a larger version back home. Philosopy ? - I took Logic and Philosophy of Science in my first year at Uni .......I found it helpful in computer programming and writing.

 

I did Puerto Galera a few times when visiting my family while at uni. My first and only scuba experience. I don't love the urban areas of the Philippines. The poverty is just a bit too much for me to take in, and I either wind up oddly calloused or really depressed (or, just as likely, both). That said I still think I prefer it to living in the west (I say typing this from Wisconsin). As a foreigner, how have you found the Philippines under Duterte?

 

The Philippines is a great country and a great place for retirement, accommodation is very cheap but as you probably know there are a few caveats that helps one stay alive. You ask about Duterte, my girlfriend's family supported his election, probably in loyalty to a local patron. I tune out on the local political stuff, as a tourist, it's none of my business to get involved. As to a real businesses or partnerships here, again the risks outweigh the likely rewards - so that's another no no from my perspective. I avoid friendships with locals like neighbors as well. If they dump their garbage on my footpath, I shovel it into my garbage bin and pay my garbage guy about $5 per month about twice the local rate. Not long back a foreigner got into an argument with a neighbor regarding his loud music, the argument got physical and a passerby knifed the foreigner and killed him. On a practical level its best to find a local trike-driver who's honest and use him for services like transportation always... nobody else in one's local neighborhood. If someone is trying a scam to extort money, you can ring your driver to come and help sort things out. Happened to me once and as soon as the driver arrived the guy left empty handed. Companionship with a local girl is often problematic because the extended family has no concept of the western nuclear family - on occasion you'll have 20-30 kin turn up uninvited for a wedding or a funeral and stay a couple of days. Being straight forward in a companionship works so long as you let your partner have free reign especially if you have offspring together, she can leave you but you can't leave her until she cut's you free voluntarily. For example, by moving on ....finding a new partner and having more children. A quid pro quo system works as a win-win game because each has something to gain by sticking together and something to loose by walking away. The simple rule is that a guy supports his companion and his companion nurtures her children. If one sticks to this deal, then the killer in the family tree will not bother you because you are showing respect to his kin. It's always 'her decision' to stay or go or if she changes her mind about splitting up ....to come back. Poverty is here for sure but its a different poverty to the west, in the USA there is a visible fourth world poverty that absent here. ... the homeless people pushing shopping cart around the cities, the beggars looking for dimes. In the third world they get some respect from the powers that be, they can build a bamboo hut on a creek bank and the local utilities will supply them water and electricity no problem. One family I knew in shack on the creek...daughters all married Japanese and American tourists they met in the malls here. now they are driving new SUVs when visiting and I have none! Best thing I ever did was to retire here, I wish I'd come decades earlier.

 

Mr Dsigned, I have really enjoyed reading parts of this thread and I admire your willingness to think beyond traditional boat building techniques and materials. I have friends in uni currently working on a concrete canoe. Even in their group, it is hard to encourage them to dream up more interesting build methods than what they have done in the past. Cheers

 

Some of the problems with traditional techniques is that ruthless competition lowers the price so much that they-look-the part then fall-a-part. Take the old galvanized roofing for example. back in the 1880 'gospel oak' was the brand in the colonial home I restored in the 1970s - still good 100 years later - no rust and no leaks. Some of the rubbish on the market now wouldn't last 20 years. I'd be tempted to design a ferro-cement tile for a long lasting roof. I'm also feed up with INTEX plastic pools, planned obsolescence is built in with a very thin plastic base that is almost guaranteed to spring leaks, so when the second I've bought gives up the ghost .... it will have to be a modular ferro-cement design that can be disassembled if need be and moved elsewhere. Most people get used to packages like microsoft this-n-that so they never have to be creative in finding a custom solution. I got sick of all the hassles with packages....they broke and years of data was .....well .....gone!!!!.... unless you pay $500 buy their special retrieval package to get it back. So I went over to linux and programming languages like php. No more worries about viruses and lost data and you can make your own designs as needed. At the moment i'm doing an extensible CMS system for writing my book because I've had years of DIY programming experience, I can do it myself. But most writers need hand-holding packages and courses on how to use them .....scrivener, zotero etc. Now the hand-holders are multi-millionaires ......the dependents are maxing out too.....but it's their VISA and overdrafts limits.

 

Part of this is because of the way the rules are written for the design competitions, and part of it is endemic in the nature of engineering programs (at least in the US). Concrete canoe competitions serve two main purposes: for the engineering students to show off their ability to perform the design process and for the industry to show off its latest and greatest in terms of materials. In fairness, engineering programs are supposed to turn out cogs: people who can design a specific part for a specific system and stay within certain requirements. They are not training people to invent or even innovate (and in fact these two things are discouraged). This isn't necessarily a bad thing, as this is what is actually needed in all those tens of thousands of engineering positions. Inventors are horribly impractical people as a rule, and engineers need to be pragmatic. People like Edison were successful as much or more because they understood implementation, marketing and the end user as much as they were good at inventing things. I think the problem lies in the fact that a lot of engineering programs wind up being attractive to kids who are DIY inventive types, who then have all of their potential for creative thinking and original thought systematically drummed out of them. I think that there ought to be some kind of parallel program that teaches more of the skills that are required to actually be successful as a creative (e.g. teaching the design cycle, but also how to run a business, raise capital, or at least how to hire good people to do it for you).

 

This is one of the things that I think often gets overlooked in "buy a used boat", especially with newer boats, and especially with multihulls. People rag on Wharrams for being built by people in their backyards, but from what I hear about the build quality of the big boys, I think you're much more likely to have an overbuilt Wharram and an underbuilt Lagoon than vice versa. And the older monohulls are often in need of major refits anyway, so you're on the hook for a ton of man hours either way (although hundreds of man hours is still an order of magnitude off from thousands of man hours). But my biggest gripe I think is that you just have to choose from what's available and that is usually that cast offs from what was popular with the jet set crowd 30 years ago. Multihulls that are floating barges that are designed to win Sunday regattas in stiff breezes and flat waters. Monohulls that were designed around box rules in the 70s. Very few boats that were built to actually do what I want to do: sail around the world quickly (fast crossings), simply (I don't need 2000 square feet of living space), comfortably (heeled over and seasick because that's the way grandpappy sailed), and perhaps most importantly cost-effectively. Vacuum bagged, autoclaved carbon-epoxy foilers are great if you don't mind dropping $90 million on your transat trimaran, but for anyone not in the .01%, the boat should be able to be built for tens of thousands (or thousands) of dollars. That's why I think concrete is worth looking at seriously. Fiberglass cloth is not that expensive. Epoxy is. Marine plywood is.

 

Boats like this kind of proves that ferro-cement boat's has huge potential, if designer take full advantage of latest advancements on CAD / materials.. just like dsigned has been saying.

2022 Starcraft SVX 171 OB Deck Boat for sale - YachtWorld https://www.yachtworld.com/yacht/2022-starcraft-svx-171-ob-8070963/ It's only 22ft long.

 

It also helps when it's mislabeled in an advert. Slightly less amazing in frp.

 

Yes, well spotted comfisherman, not the best example of ferro-cement construction

 

Just another kick at the can. Ferrocement is only a bargain if labour is free, and it's okay if the final product is a really crappy boat that cost only slightly less than a good boat.

 

Just an example that the best ferro cement is when it turns out to be frp....

Outside of barges and bulk carriers, even Jon boats have the hull as only a small part of the cost. That's the big flaw in the theory. My last boat the hull was 16 to 17k in material for the hull in just under 375k in components. With the resin and laminate price hikes that will still only put it in the low 20s. Less than the increase on just the main an gear. Hull cost isn't irrelevant but unlike the 60s it's a tiny percent.