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BillAU · 06-07-2010, 20:31

G'day mates,

This is for any of you FC Hartley owners...I'm curious to know

Do you believe a 30' Hartley Twin Keel FC Yacht can be safely sat on the beach on her twin keels. i.e. sailed up to the beach on a high tide and anchored there till the tide went out, leaving the boat sitting level on the sand. Are the FC twin keels strong enough to take the weight?

Bill
Australia

Tony-Cross · 24-07-2010, 17:54

Having owned a Ferro Cement 45ft Yacht for a number of years, I can give my perspective on the issue. My boat was a sail boat designed by Bruce Roberts built in 1979.

I had a couple of areas of the hull where rust was leaking out, after grinding out the
area, then filling with a mixture of Portland cement and 2 part epoxy (This has a very similar expansion co-efficient to the original material) this was easily fixed, I have to tell you that there is no stronger bog known to man than this mixture except perhaps breakfast cereal leftovers left in the bowl for a few hours !

The weight of the boat was exactly the same as a GRP boat 16 tons.

The hull was very stong, I once challenged someone to damage the hull with a hammer, they could not it simply bounced off causing his teeth to chatter.

All in all the boat was a very good one, however I would never buy another one and the reasons are that you cannot insure them, I tired every way including a full survey, in the end the only insurance I could get was liability insurance for the marina. The other issue is that when you try to sell your boat no matter what
you have added and improved on the vessel you will only get less than 50%
that of a similar GRP boat.

Sorry it's not as technical as the other replies.

BillAU · 24-07-2010, 18:13

Quote:

Originally Posted by Tony-Cross

Having owned a Ferro Cement 45ft Yacht for a number of years, I can give my perspective on the issue. My boat was a sail boat designed by Bruce Roberts built in 1979.

I had a couple of areas of the hull where rust was leaking out, after grinding out the
area, then filling with a mixture of Portland cement and 2 part epoxy (This has a very similar expansion co-efficient to the original material) this was easily fixed, I have to tell you that there is no stronger bog known to man than this mixture except perhaps breakfast cereal leftovers left in the bowl for a few hours !

The weight of the boat was exactly the same as a GRP boat 16 tons.

The hull was very stong, I once challenged someone to damage the hull with a hammer, they could not it simply bounced off causing his teeth to chatter.

All in all the boat was a very good one, however I would never buy another one and the reasons are that you cannot insure them, I tired every way including a full survey, in the end the only insurance I could get was liability insurance for the marina. The other issue is that when you try to sell your boat no matter what
you have added and improved on the vessel you will only get less than 50%
that of a similar GRP boat.

Sorry it's not as technical as the other replies.

G'day and thanks for your views, at the price I can buy a 32ft Samson C-Mist, (she needs work below deck) or a 30ft Hartley Bilge Keel, (she needs a new engine and main sail) I would not be concerned about full comp' insurance, I would have 3rd party but as for full comp'...I don't think so.
As for selling when I'm done with the boat...If I change my mind and bought one...I would not try to sell her, I would give her to one of my adult children...Or one of my grandkids.

Thanks for your views.

Bill AU

Nibiruwayne · 24-07-2010, 18:35

Jeff, great post on ferro cement. Looked at one 20 yrs. ago, didn't buy. WE all seem to defend our decisions.

caps38 · 25-07-2010, 21:46

Hi Toni-Cross
Caps38 here. Thanks for the reply. Did you mix sand with the portland cement and epoxy or just portland cement and epoxy. We have done some experiment mixes with portland, sand and 2 part epoxy and it is rock hard. We have a large area that needs repair and getting the right clean sand is a bit of a problem. Do we need to use sand. Also we have insured our boat for liability only. Friends of ours were going to insure with Edward William who say they will insure ferro yachts but they were concerned it might not be the real deal so havent done so. We will pass out yacht onto our son who is a keen yachtie. But that wont be for a long time yet!

Tony-Cross · 25-07-2010, 22:35

Quote:

Originally Posted by caps38

Hi Toni-Cross
Caps38 here. Thanks for the reply. Did you mix sand with the portland cement and epoxy or just portland cement and epoxy. We have done some experiment mixes with portland, sand and 2 part epoxy and it is rock hard. We have a large area that needs repair and getting the right clean sand is a bit of a problem. Do we need to use sand. Also we have insured our boat for liability only. Friends of ours were going to insure with Edward William who say they will insure ferro yachts but they were concerned it might not be the real deal so havent done so. We will pass out yacht onto our son who is a keen yachtie. But that wont be for a long time yet!

Hi Caps38,
I tried the mixture after reading it in one of the books on ferro cement boat building, I think it was Bruce Binghams book.
After experimenting I found that equal parts of portland cement and the combined mixture the epoxy, (I used the West System) seemed to work the best.
I also tried using the microbeads West use as a bog but didn't get such a good result, it tended to be spongy and sag.
The problem you face is that when the filler expands and contracts it must be exactly the same as the ferrocement hull.
After mixing you find the mixture turns pitch black, a tiny amount of this ended up on my drill and I needed a chisel to remove it when it was dry.
This tends to go off pretty quick suggest you use in the cool of the evening but not if it's a damp one.
The areas which I filled using this method were maximum the size of a piece of half A4 paper. When I hit the steel after grinding out the cement area with a grinder with a metal cutting disc, I carefully ground the steel clean, removing any rust, then lightly painted it with kill rust paint, this provided a good key for the mixture.
I'm not sure that you need sand unless you have really large area, I once helped someone fix a ferro cement boat after it had run onto rocks leaving a huge hole in the bow she had been salvaged into the marina hardstand in Darwin, after straightening the steel-mesh out he simply hired a concrete mixer then re-plastered the area, he then watered it on and off for 2 days, he was very happy with the result !!
The hull of my yacht was counterstern so I had one area where I had to apply this against gravity however
I applied a small amount let it dry then applied the finishing fill, from memory it didn't even sag. These area's never showed any problems after, some were also above the waterline, I ended up removing all the paint then re-epoxying 2 coats then the whole hull primed and couple of top coats of 2 pack paint.
I also used this bog to fix a damaged part of the toe rail where the previous owner had hit a jetty and damaged the staunchion and broken away the concrete toerail, I used Ramset chemical bolts to reattach the base of the staunchion into the concrete deck.
The insurer I used was Club Marine who were happy to give a very good price for liability insurance for Cullen Bay marina in Darwin after the survey.

Cheers Tony

Tony-Cross · 25-07-2010, 22:58

BTW here is a link to an image I found, this was after the 2nd coat of epoxy paint

http://www.cruisersforum.com/forums/...cture6299.html

smallyachts · 26-07-2010, 01:53

Hi Tony,

Could you tell me which Bruce Bingham book you found this formula in?

The only reference I have ever seen by Bruce Bingham to a ferro mortar formula with resin in it is Fer-A-Lite which does not have Portland cement in it at all.

Tony-Cross · 26-07-2010, 02:45

I no longer have the book, it was a soft cover book which concentrated on ferro cement yacht construction methods.
Cheers Tony

BillAU · 26-07-2010, 03:32

I found this site providing information on FC hull repairs, it may help you, if you don't find what you're looking for on that page/site, try these books from the Hartley Site and good luck with things.

smallyachts · 26-07-2010, 03:34

Thanks Tony,

Would it have been "Ferro-cement Design Techniques and Application" by Bruce Bingham?

It is the only one of his I am familiar with that deals exclusively with Ferro-cement.

Darr

Tony-Cross · 26-07-2010, 04:02

Yes it may have been that one, when I purchased the boat there were several books on the subject and the Bruce Bingham springs to mind.

Cheers Tony

smallyachts · 26-07-2010, 19:22

Ok, I could not find the reference to the epoxy portland mix in Bruce's book, but I have found references to it in other areas (thanks to BillAU and others), however none of the references discusses a basic question I have.

Since the mixing of water and portland cement by the process of hydration creates tricalcium silicate hydrate, in other words concrete.

and...

Epoxy which consists of a resin and hardener that when mixed causes a chemical reaction that creates highly crosslinked chains at the molecular level thereby gaining its strength.

What process is involved, what chemical reactions occur and what is the chemical composition of mixing portland cement with epoxy?

Is not the Portland cement just being used as a thickener, similar to say talc or micro balloons.

banyandah · 26-07-2010, 20:15

Hi everyone,
As a longtime ferro owner, just thought I'd add a few comments. Banyandah was home built by Jude and I then sailed around the world for something like sixteen years, covering over 100,000 miles. She then was hoisted out onto on our front lawn for another sixteen or was it eighteen years, rebuilt, and I can show you some major sections totally rebuilt, then relaunched and has covered another 15,000 with her new rig.

Yes ferro is heavier than many other vessels. But on the positive side, they sit very nicely at anchor, are quiet, feel strong, and I reckon we sit at anchor a lot more than sail the sea. Banyandah was flipped in the North Pacific one winter long ago, ripped her dodger off but the sea can't damage a ferro hull, only hitting rocks or pointy things. Then they break up rather quick I'm sorry to say. Easy to maintain. but they do have their unique problems, blistering antifouling can be one. Problems start where salt water is on both sides of the hull like chain locker, top of bilge. All said, they MUST HAVE BEEN MADE WELL. Air entrapped within the mix is going to lead to big trouble.

I raised my mast during the rebuild, added another 8' to the 42' off the deck. Took away the mizzen. Is she more tender? Maybe a titch, really hard to say, but we go faster in light winds for sure. We don't only sail tropical waters, twice round Tasmania these last two years, and crossed the Aussie Bight where the big stuff rolls through.

I repaired my hull using epoxy and a by-product from power stations, a carbon particle. Only used portland cement once. Sets like a rock, and quick from the heat given off by the cement. Ferro needs flexibility so not so sure about it, I'll leave that to someone with more experience.

Hope that helps, Oh yeah, resell value stinks. But the "B' is family now. Never sell her, might just put her on the land as a museum one day like the Cutty Sark.