Conference unifix::sailing

    Ferro-cement construction was all the rage in Australia and NZ about 15
    years ago.  I seriously considered doing it and got study plans etc. 
    In the end I went and bought a used fibreglass sailing boat.
    
    A number of people did go ahead and build cement boats, sail and motor.
    
    One can have end-less arguments about the pro's and con's, I'll give a
    few below.  But over the years cement has fallen out of favour and
    there are heaps of abandoned cement hulls sitting in lots in Australia. 
    Each one represents years of hard work gone to waste.  Why?  It's an
    amateur medium; if the person building it is skilled, uses the best
    materials and is conscientious at every stage you get an excellent
    product.  But unless you watch you can't tell and, at least in
    Australia, you cannot get any insurance unless a Lloyds inspector has
    watched every stage of construction.  That in itself drives up the
    cost.
    
    Pros/cons
    
    It's strong, it's basically a steel boat with cement
    filling the holes in the steel.  There are records of cement boats
    hitting coral reefs and breaking the reef.  
    
    It is suitable for amateur construction.  But so is steel, c-flex, wood
    (within reason)
    
    It's cheap.  Yes, but the hull is only a small portion of the toatl
    boat.  Overall savings are probably less than 10%.
    
    It's maintenance free.  No boat is maintenance free - it needs as much
    as any glass boat.
    
    The strength is gained by hull thickness.  Unless you use some very
    fancy techniques (no longer amateur material) minimum hull thickness is
    about 1.5 inches.  This really makes it unsuitable for a boat under
    30'.  And you don't get a "fast" (read acceptable) boat until the 40'+
     range.  
    
    In summary, a cement boat is very strong, very safe IF built to a high
    standard.  IMHO it's not a material I would build in, and certainly
    NEVER buy.  The cost argument was demolished for me by the argument
    that I would be financially better off (and have some resale value)
    by having a steel/glass/wood hull built by a professional and spend the
    time I would have invested in the building on a second job to pay for
    it.                                                               
    
    

    Soundings had an excellent article this summer (I can't remember which
    month) which revisited ferro cement and what went wrong.  There was
    horror story upon horror story and while the article cited people who
    had built good boats and were happy - the overall conclusion was that
    this was a construction fad that didn't merit its promise.  Even the
    naval architect who lent his name to embracing ferro cement, went
    underground having been ostracized in his profession.  
    
    Get the article and it will convince you to buy a readily available
    fiberglass hull and finish it. 
    
    Bob

Having seriously considered FC construction of a cruising boat with a 
friend back in the early '70's, we looked at perhaps 6 or 8 hulls in 
construction, a couple completed, and talked with *many* people, and yes,
bought a set of Jay Benford's plans. 

The clear consensus was that it was less a question of the material's
quality than of construction technique.  It has its own set of properties,
some of them quite useful and good, and no one has ever faulted the
better built hulls for lack of strength.  Previous comments on scale are
accurate: 40' is about the smallest practical use, unless ponderous weight
matters not one whit.  Many fishing boats are still built in FC, since 
it's cost effective where perfect fairness isn't required (thus allowing 
faster construction), where strength and low maintenance are valued, and 
impact resistance with easy (if not necessarily cosmetic) repair 
important.

Construction technique involved building an armature of rebar, bending and 
tying it to frames so that it would hold the precise shape desired.  Then 
"chicken wire" (specialized 1/2" grid, actually) was tied inside and out 
-- this is critical, as it's the main tension member in the skin; the 
cement is obviously only good in compression.  Properly done, the 
armature with layers of wire inside and out is tight enough to ring like a 
giant gong (remember those J. Arthur Rank movie openings?) when struck 
with a sledge.

Cement must be applied in a single operation, as wet must always bond with 
wet.  Wetness/dryness is also critical, as it must stick to the armature, 
yet easily work its way into every void.  The cement must cover all the 
wire, but not be too thick over any of it.  And you have to be careful not
to work the cement more than minimally, or the fine aggregate will
separate from the cement and puddles of water will form inside and out.
That's where we decided amateur plastering wasn't such a good idea;
professional plasterers are available, but then the cost goes up. 

In the end, we decided A) to buy a good FG hull and finish it out, and B) 
then gave up because even a good FG hull was more $$$ than we had to put
in at the start.  Ah, dreams of youth.... 

J.

	Having just bought an 8 year old ferro-cement boat, after previously 
rejected the purchase of a fc boat for the reasons given in the previous
replies, I thought I would put my tuppence worth in.

	Previously I had rejected fc because most are amateur built and are 
therefore of variable and often very dubious quality. When building a fc boat 
it is very important that the wire frame is smooth and true, too often not 
enough time is spent at this stage making sure that each layer of the wire 
frame is good. If the wire frame is not smooth and rigid then the end result
is a boat which is crinkled (for want of a better word) and has not got 
the strength it should have. Before I bought the boat I saw photographs and 
surveyors reports on each of the stages of construction. I also bought it off 
the person who built it, who I knew before I bought the boat.  Also the 
local college had done strength tests on a test piece made from the cement so 
I was sure that the boat had been built to a very high standard, and if anyone
is thinking of buying a fc boat I would recommend not thinking of a boat without
surveyors reports at each stage of construction.

	The boat is 35' and again I would not go smaller in size, it weighs 
8.5 tons, so it is not a racing boat. The reason I bought it was that I am 
thinking of taking some time off and doing some ocean sailing.

	Having looked at fibreglass boats of the same age I found that I was 
paying more money for a boat that didn't have anything like the equipment
nor were they in as good a condition, as Chrysalis.

	As always it depends on what you want a boat for, if you want a 
racing boat, or performance cruiser forget fc. If what a comfortable boat for 
ocean sailing at a reasonable price, then fc might be worth looking at, but 
be careful when looking at a fc boat. Make sure it is very well built, with 
good surveys otherwise don't touch it however cheap it is.

	I hope that this is helpful to anyone considering a fc boat.

		Stephen Kell

    Hello everyone ,
    
    I am currently interested in the construction of hulls from
    FERROCONCRETE . I would be most interested in any comments
    pros , cons , technical advise , horror stories etc.
    Has anyone out there tried this approach ?
    
    Am I nuts to even think about it ???
    
    Thanks in advance ,
    
    Chris

    I'd guess you are reading some 10 year old books. THis was a real hot
    idea then, but seems to have died totally in the last few years. There
    were lots of hulls started, and then left to rust away. I think part
    of the problem is the classic one of not really understanding the costs
    of a boat- the hull itself is a small part of the total- interior
    furnishings, rigging, engines and mechanical systems etc etc. all wind
    up costing far more than the hull. So do you want to put all the mopney
    into those items, and hang them around a FerroConcrete hull?

    Professionally done, it can be strong but it is probably tough to find
    anyone to do it professionally.  For the price, you can probably find a
    steel hull or even a glass hull for completion.  Probably a sounder
    choice to hang your expensive stuff on :-).
    
    Brian

    I know this is the sailing conference but I will provide this info as a
    price point FYI. I recently looked at buying a 37' Tolleycraft
    convertible sedan fiberglass hull brand new from a boat builder who had
    purchased the mold from Tolley when that style went out of production.
    It was complete including the superstructure and flying bridge with
    windows installed. Interior bulkheads (wood) were glassed into place.
    No hardware or mechanical items. He wanted $27,000. Not bad for a boat
    that would go for $200K plus.
    

Ferrocement or not, it's tough to imagine not being able to buy a sound 
vessel in today's market for less (perhaps even considerably less) than 
the cost of building one, no matter what the material.  The main reasons 
now to consider building oneself are:

	- For the fun and learning in it.  (Ask Ross Faneuf, who 
	  intersperses moments of great joy and pride with time in the
	  Moaning Chair in his quest for a Finished Home-Built Boat. )

	- For features just not available elsewhere.  One has to have some 
	  fairly idiocyncratic ideas not to find something on the market
	  that reflects most any style of reasonable thinking. 

	- For something ultra cheap, perhaps made of plywood-trouv� and 
	  metal scaps found at automobile accident scenes.  ;-)

I'd guess a week around Florida or some other locale of oft-neglected 
boats would turn up some very surprising values, if you knew what to look 
for and what to avoid.  Some of the broker listings these days are close 
to astounding...there have to be some even more amazing owner/seller deals 
out there.  (Wish I was in the market!)

J.

    re .8
    
    >I recently looked at buying a 37' Tolleycraft convertible sedan
    >fiberglass hull brand new from a boat builder who had purchased the
    >mold from Tolley when that style went out of production.
    
       Was he making Gilligan's Island S.S. Minnow reproductions? ;>) ;>)