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Old 10-09-2003, 12:29   #16
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Well, it is becoming clear to me this is becoming a religious discussion. So I'll try to be brief.

- Your thickness calculations are still incorrect Jeff. You are including the thickness of UNCOMPRESSED netting, which is certainly not the case when using 1/2" hexagonal galvanized bird mesh tied -tightly- to the arnature. Once complete the thickness is barely above the thickness of the main rods

- Re: Fiberglass hulls - I am getting my statement from a Marine surveyor who has done thousands of boats for insurance survey. HE says old solid FG boats are, Quote: "Built like tanks" and that modern boats are 'Rarely' as strong. I'm sure he was talking in 'most of' terms, and there will certainly be exceptions.

- Much of the information I am getting about FC is from two primary sources. (1) Cecil Norris S.N.A.M.E. and (2) Colin Brookes S.N.A.M.E. For those if you whom don't know, this is the much lauded Society of Naval Architects and Marine Engineers. It is an international organization made up of recognized professionals in Naval Architecture. Colin recieved the title 'Master' from SNAME. This distinction is very rarely awarded to individuals on the basis of accomplishment, and he recieved it in recognition of his accomplishments in the realm of Ferrocement. So you can understand when I trust his word on things, considering the USCG and Lloyd's use him to survey FC boats for commercial purposes. His knowledge is much, much more than theoretical. And Cecil Norris designed many. many FC boats for both commercial and recreational purposes. He has since moved on from FC as a material, but in a conversation I had with him, he told me it had nothing to do with FC as suitable material for shipbuilding, "on the contrary. FC is an admirable material. However, the problem of labor costs in mass production always comes back to haunt. I fear FC will always remain a secondary material."

And on, and on, and on....

So, I'd like to end this board debate, which is no doubt amusing the other folks online here. Jeff, if you would like I would be more than willing to take this up via email. My address should be public, and if not I will publish it here for you to have. It seems we are having the kind of spirited debate that science craves. :-)

--Timothy
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Old 11-09-2003, 07:16   #17
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This does seem to be an issue of faith with you. To me it is a simple matter of engineering and understanding the materials involved. I do think that this is a good forum to have this discussion, where it can benefit more than just you and I and where others can provide substanative input into the discussion. From the email that I have recieved we are not the only ones reading and learning from this. That said, I am also open to exchanging email if you would prefer. My email address is burr.halpern@annapolis.net

To reply to your comments:

The thicknesses that I quoted come from the websites that you mentioned, literature from Hartley that describes their building process and are consistent with ferrocement design manuals.

Few marine surveyors have an engineering background. It is easy to mistake a thicker hull for a stronger hull. In recent years there have been increasing interest in the aging fleet of early FRP boats. These articles seem to universally conclude that these early laminates are decreasing in strength as the resins, which started out brittle continue to become increasingly less ductile and the reinforcements which also were less resilient show signs of fatigue. The insurance industry reports that this increased weakness is resulting in more expensive damage in comparatively minor impacts on older boats which is partially why you see more insurance companies declining insurance on older boats. I and my surveryor friends repectfully disagree with your survey. Some of these papers and articles are available on line.

As a former member of SNAME (Society of Naval Architects and Marine Engineers), I understand what it means to belong to SNAME and therefore be permitted to put SNAME after your name. I am not in disagreement with much of what I have seen quoted from Mr. Brookes. They seem to completely correspond to the points that I have made in this disscussion.

In any event, I think this has been a good discussion of Ferrocement. I think that it is helpful to understand the strengths and weaknesses of the various material options. I do not advocate that there is a universally right, one size fits all boat building material that will work for all sailors. (Heck depending on how you count them I have had boats built using 7 or 8 different techniques and materials so their wasn't even a universally right, one size fits all boat building material for even this one sailor.)

I am certainly open for any substantive information that you or anyone might wish to add to this discussion. I think that I learn a lot from this kind of discourse.

Respectfully,
Jeff (not Jay)
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Old 11-09-2003, 08:41   #18
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Jeff H and knome,

With all due respect, both of you seem to be very knowledgable about ferro cement boats. However,when I read your comments while debating this subject, I can't help but to visualize two guys standing toe to toe,one shaking a slide rule,and the other shaking a book at one another For the average "Joe" like me, if I were considering buying a ferro cement boat, I would definately want to hear more input from people that have actually owned this type of boat. The only two other posts around this subject here is by one owner that is very pleased with his ferro cement boat.The other concerns a boat owner whom has allowed his ferro cement boat to waste away.Not exactly a convincing poll.Isn't there anyone else reading this that owns,or has owned one of these boats?
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Old 11-09-2003, 08:47   #19
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You're right, of course Stede. Sorry for the diatribe!

I have second hand knowledge of owners of 6 FC boats.. and in almost all the cases:

1) They love the boat
2) They spend less to maintain the boat then their neighbors and still have a sterling vessel
3) People dont even know they own a FC boat and mistake them for FG or wood

So, I hope some other actual owners out there will pipe up!

--Timothy
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Old 11-09-2003, 18:42   #20
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Fittings

My question is, how do you go about putting in thruhull fittings or add deck fittings like cleats. Do you use rotary hammers and core drills? It seems like a lot of effort to do construction or modifications.
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Old 11-09-2003, 22:41   #21
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Well, I have been following this debate with extreme interest because it was my little query which started the whole thing! I have to admit that I will need to leave the engineering-type information to those more knowledgeable, but I would like to report that my partner and myself have just bought a ferro-cement boat...well, made an offer anyway.

My partner has spoken to the afore-mentioned Colin Brookes and has purchased his book. We have spoken at length with the current owner of this FC yacht - he has not had any trouble whatsoever with it, and is only selling it because, despite trying, he cannot interest the wife in sailing. He bought it off the hard-stand without even bothering to get a survey! How's that for trust!?

Anyway, I hope the offer is accepted as this beautiful little yacht has been afloat for 20 years now with absolutely no problem, and we are looking forward to sailing her far and wide!

I've attached a photo.

Cheers,
Marlene
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Old 12-09-2003, 04:46   #22
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Knome,

No need to apologize for the debate.I'm sure there has been some interest in reading the comments.I have to some extent,but I am a skeptic of number crunching and reference books.Don't get me wrong,I believe there is value in both.It's just that I've worked for years with a major corporation as kind of liason between engineering and maintenance.I can't tell you the number of times I've sat in meetings and listened to engineers explain why something wouldn't work because "the numbers didn't support it." After much debate,we sometimes went forward anyway and found that it did work. It's not that their numbers were wrong,it's just that sometimes they would miss certain aspects of an application because they simply weren't aware of it.On the other hand,I've heard tradesmen challenge the numbers,and they were wrong.When the two couldn't come to an agreement,my team leader usually left the decision up to me. When he did,I usually fell back to this scenario on how I would make my decision. If it was a totally new design,with no data to support it's capability, then I would rely on the engineers. If we weren't re-designing the wheel,I would rely on the tradesmen. In the case of ferro-cement boats,I think the "proof in the pudding" would fall to the tradesmen,which in this case is the owners of the boats.I mean after all, some CEO sitting behind the desk chewing the fat cigar has already made the tough decision some time back to invest hundreds of thousands of dollars to tool up a process to build these types of boats.At that time,I'm sure the decision was made based on the number crunching,and conferring with available experts concerning the technology. In essence, the boats were built and regardless of what the numbers or experts now say, the only thing we as sailors are concerned with is whether the boats are worth spending our hard earned money for them? For me to make that decision,I would want as much available input as possible from people that have actually owned and sailed the boats. Now,I am the one that must apologize for rattling on
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Old 12-09-2003, 05:12   #23
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Thru hulls are not all that easy to add. I do not know the current thinking on installing thru-hull fittings but when I was more involved with ferrocement boats, the recommendation was to build up extra thickness in the area where the thru-hull was to be installed and to add extra reinforcing around that area of the hull. A wooden plug made from a closet pole or dowel was inserted on the jig at thru hull locations, and the reinforcing was stopped short of the dowel. There are issues with adding thru hulls after the fact because you are cutting through the steel reinforcing providing potential access to the reinforcing for water to start corrosion and also the potential for electrolysis between the steel reinforcing and typically bronze thru-hull fitting. The use of bronze thru hulls and electrolysis on FC boats was a heavily debated topic in the 1970's and early 80s and I don't know how that issue resolved. The last FC boat that I was on used Forespars' marelon plastic fittings which is actually a pretty good solution.

Most Ferrocement boats that I have been on have had fiberglass over plywood decks and cabin structures, essentially built as you would a wooden boat. This makes adding deck fittings much easier and actually helps keep the weight out of a weight sensitve area of the boat. Having the weight of a Ferrocement deck that high above the VCB and roll axis would raise the VCG pretty dramatically and result in a boat that had less stability and a pretty uncomfortable motion.

Of course using fiberglass over plywood decks and cabin structures is a pretty high maintenance solution over the long haul and cited as one of the reasons that ferrocement boats were seen as being one of the highest maintainance materials in the study of long term maintainance costs that I believe was performed by 'Boat Builder' magazine some years back.

Respectfully,

Jeff
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Old 13-09-2003, 04:37   #24
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Fittings such as skin fittings should be positioned against the hull and circle marked using a perment felt tip marker around the fitting.Then using a .25" masonry bit and a high speed hammer drill bore aseries of holes close to each other all round the circle,sothat the finished hole is at least .25"larger than the fitting when finished.Get an accomplice to hold a mash or sledge hammer againist the inside,while break up the centre of the hole with a hammer,wire cutters and a hacksaw to cut any mesh or steel rods.The fitting is then given a liberal coating of grease on the thread,flange and nut.Apply a large amount of epoxy filler to the area around the hole in the hull as well as inside and outside including covering any area that may have been chipped when cutting the hole.While the filler is sill soft,carefully push the fitting through the hole keeping it centred and finger tighten the nut on the inside.When the epoxy has set undo the nut inside then unscrew the skin fitting from the hole the grease will stop it from sticking.Then using a sander,smooth both out and inside surfaces back level.Fitting is then refitted with non harding mastic i only use stainless 316 fittings.
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Old 13-09-2003, 10:17   #25
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New Boat

Hi Marlene,
Just courious, did you find you boat yet?
Ib
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Old 13-09-2003, 10:26   #26
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FC Boat

Hi again,
I just saw your post above, that was after I asked if you had found your boat. Hope everything work out well.
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Old 15-09-2003, 04:43   #27
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Below is an interesting comment I ran across in regard to the integrity of different boat hull construction methods

"Ferrocement is the only material that has no advantages other than inexpensive construction materials. It is the most labor-intensive material to build with, is difficult to finance, insure or repair, and has the lowest impact resistance of any material. Having said this, I have met two cement cruising boats that have completed two and three circumnavigations respectively."

Source:
http://www.mahina.com/cruise.html
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Old 22-09-2003, 14:27   #28
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Ok Stede, Here is the answer you`ve been looking for. I`m the proud owner of a Stan Huntingford design Ferro-Cement boat. It`s called "Island Chief". He`s 60ft in length and weighs in at a modest 64,000lbs. Wanda,my girl friend and I live on the boat full time and have done some sailing with it. I`ve also done alot of sailing on other material boats as well. From 24ft to 70ft. and I must say by far this is the most comfortable boat I`ve ever been on. All of this hoopla about getting insurance is crazy. Mine is insured through State Farm. As far as value on Ferro boats, I have to agree it`s strictly the market. I wouldn`t hesitate to put my boat up to any other 60 footer out their. It may not come out on top, but it would rank very high in overall. I got real lucky with boat. Like you I did my homework before I bought it. I found alot of junk out their and I found some very good boats. Find out as much as you can about the about the boat your looking at. If you want, I could put together a list of questions to ask. Some of which the current owner may or may not be able to answer. However the preveous owners and builder/designer could. I`m more than happy to share the information I`ve gathered. What size are you looking for? Where are you located? What type of sailing will you be doing? Buy the way my boat is a #2 Hull. And the #1 is sailing in St THomas. The Boat is called "New Horizons". This in it self should say something about a properly designed boat. Some of what the previous people have said is correct, some is not. I would be more than happy to give you the build specs of the Island Chief. It may give some idea as to what to look for. You can e-mail me at islandchief60@yahoo.com
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Old 22-09-2003, 14:52   #29
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Ok Stede, Here is the answer you`ve been looking for. I`m the proud owner of a Stan Huntingford design Ferro-Cement boat. It`s called "Island Chief". He`s 60ft in length and weighs in at a modest 64,000lbs. Wanda,my girl friend and I live on the boat full time and have done some sailing with it. I`ve also done alot of sailing on other material boats as well. From 24ft to 70ft. and I must say by far this is the most comfortable boat I`ve ever been on. All of this hoopla about getting insurance is crazy. Mine is insured through State Farm. As far as value on Ferro boats, I have to agree it`s strictly the market. I wouldn`t hesitate to put my boat up to any other 60 footer out their. It may not come out on top, but it would rank very high in overall. I got real lucky with boat. Like you I did my homework before I bought it. I found alot of junk out their and I found some very good boats. Find out as much as you can about the about the boat your looking at. If you want, I could put together a list of questions to ask. Some of which the current owner may or may not be able to answer. However the preveous owners and builder/designer could. I`m more than happy to share the information I`ve gathered. What size are you looking for? Where are you located? What type of sailing will you be doing? Buy the way my boat is a #2 Hull. And the #1 is sailing in St THomas. The Boat is called "New Horizons". This in it self should say something about a properly designed boat. Some of what the previous people have said is correct, some is not. I would be more than happy to give you the build specs of the Island Chief. It may give some idea as to what to look for. You can e-mail me at islandchief60@yahoo.com
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Old 22-09-2003, 22:10   #30
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Hi there Islandchief60,
Yes please...as the owner of a ferro-cement boat I would very much appreciate your list of questions to ask an owner..... especially as my partner and myself are currently just at the point of purchasing one!

We have organised a survey and this is happening on Friday (in 3 days). Insurance is no problem and we have already gotten a quote for comprehensive insurance which was quite reasonable. Everyone said that we might have trouble getting a spot in a marina but the local Royal Yacht Squadron welcomed us with open arms and have offered full access to their facilities. There doesn't seem to be any bias with regard to FC yachts in this part of the world (Australia).

We plan to initially sail these Southern waters but the eventual aim (not too far away) is to liveaboard and sail to other parts of the world.

Thanks...look forward to your message,
Marlene
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