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03-12-2005, 19:23
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#91
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Senior Cruiser
Join Date: Dec 2003
Location: Marlborough Sounds. New Zealand
Boat: Hartley Tahitian 45ft. Leisure Lady
Posts: 8,038
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Cement comes from several sources in NZ. One famouse cement was Golden Bay, but the real Golden bay site has scince closed.
Kai Nui, Salt is bad bad new's. It stays in the cement and as the cement hardens, it turns back into a crystal. Then when it is exposed to water again, the crystal disolves and leaves a small pit. Many cystals can lead to a very porouse and weak plaster. I have just seen a hull this morning that I suspect may have had such a situation. It is being restored and I have just seen it for the first time. The plaster has small shell particles in it and the outer plaster skin is very pitted. I suspect someone has used sand from a beach. The hull has been sandblasted back very hard and has showed up cracks all over it. These are seriouse stress cracks as they are all around internal stiffenings. I don't know what this guy is going to do. I dont' have the expertise to help with suggestion with something this bad. But I am going to watch closely and see what he does and how,in the aim to learn something from him. Let's hope it is positive.
__________________
Wheels
For God so loved the world..........He didn't send a committee.
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03-12-2005, 19:55
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#93
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Registered User
Join Date: Sep 2005
Location: Phoenix, Arizona... USA
Posts: 2,386
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Yeah, right next to the neighborhood Walmart. ;-)
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20-12-2005, 23:06
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#94
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Guest
Posts: n/a
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20' seas are coming tonight. The surf has been unreal the past few days. It will be interesting to see if the cement ship at Capitola survives. They have evacuated the mobile home parks in Aptos along Seacliff State Beach. Big concerns for the people living on the hook at Capitola.
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21-12-2005, 21:52
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#95
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Registered User
Join Date: Sep 2005
Location: Phoenix, Arizona... USA
Posts: 2,386
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Huge Waves Crash Onto California Coast
Dec 21, 11:08 PM (ET)
LOS ANGELES (AP) - Huge waves pounded the Southern California coast Wednesday, forcing the rescue of struggling surfers, closing piers and causing minor flooding.
The National Weather Service warned of breakers 15 feet to 20 feet or higher in coastal areas northwest of Los Angeles, and waves exceeding 15 feet along San Diego County.
The swells were generated by storms in the Pacific, but the first day of winter in Southern California was summerlike and crowds gathered on beaches to watch the churning surf.
The piers at Santa Monica, Manhattan Beach, Hermosa Beach and Redondo Beach were closed, said Los Angeles County lifeguard Capt. Terry Harvey. In San Diego County, piers at Ocean Beach and Imperial Beach also were closed.
"We're trying to warn surfers that we have high surf and strong rip currents and they should use extreme caution," said Venice Beach lifeguard Capt. Mike Cunningham.
At Seal Beach, a surfer trying to ride big waves broke a leg when he was thrown into the sand, said lifeguard Capt. Ross Pounds.
Huge surf also pounded San Diego's beaches. In Encinitas, a north San Diego suburb, thousands of spectators - mothers with strollers, bicyclists in helmets, and businessmen in suits and ties - stopped for a glimpse. In San Diego, extra lifeguards were posted.
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21-12-2005, 22:27
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#96
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Guest
Posts: n/a
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They did not come in here as big as advertised, but impressive none the less. I guess the cement ship lives to see another storm.
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07-01-2006, 12:56
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#97
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Senior Cruiser
Join Date: Dec 2003
Location: Marlborough Sounds. New Zealand
Boat: Hartley Tahitian 45ft. Leisure Lady
Posts: 8,038
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Roverhi,... I have been doing some homework for you, in regards to your very important question on "how do you make new cement stick to old"? OK... there are two important aspects to this. First is in further reply to your "concrete path" description. It's important to remember that you aren't dealing with 'concrete' as such as found in a path. The reason why old and new concrete will not join well, is because the main medium in 'concrete' is the stones. The cement is bonding the stones together and as there is not a lot of cement in the concrete mix ratio, cement will not or can not bond to itself very well. Thus a concrete slab will crack at a join. The cement mix in boat construction is a different story. The cement is of very proportion to the sand mix. The cement over time will indeed continue to chemicaly bond together as it cures.
But here is the important point No.2 in a repair. PVA is used as a bonding agent. Yep, that is simple white wood glue. The old cement edge is kept wet with water and the PVA as the new cement is applied. Small repairs can have the PVA mixed into the cement mix as well. The finished result is a strong water tight bond that continues to get stronger with future curing. One such repair done on a local boat here, was surveyed about 10yrs later and no one could find were the repair was carried out.
__________________
Wheels
For God so loved the world..........He didn't send a committee.
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07-01-2006, 12:56
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#98
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Senior Cruiser
Join Date: Dec 2003
Location: Marlborough Sounds. New Zealand
Boat: Hartley Tahitian 45ft. Leisure Lady
Posts: 8,038
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Roverhi,... I have been doing some homework for you, in regards to your very important question on "how do you make new cement stick to old"? OK... there are two important aspects to this. First is in further reply to your "concrete path" description. It's important to remember that you aren't dealing with 'concrete' as such as found in a path. The reason why old and new concrete will not join well, is because the main medium in 'concrete' is the stones. The cement is bonding the stones together and as there is not a lot of cement in the concrete mix ratio, cement will not or can not bond to itself very well. Thus a concrete slab will crack at a join. The cement mix in boat construction is a different story. The cement is of very proportion to the sand mix. The cement over time will indeed continue to chemicaly bond together as it cures.
But here is the important point No.2 in a repair. PVA is used as a bonding agent. Yep, that is simple white wood glue. The old cement edge is kept wet with water and the PVA as the new cement is applied. Small repairs can have the PVA mixed into the cement mix as well. The finished result is a strong water tight bond that continues to get stronger with future curing. One such repair done on a local boat here, was surveyed about 10yrs later and no one could find were the repair was carried out.
__________________
Wheels
For God so loved the world..........He didn't send a committee.
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07-01-2006, 12:56
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#99
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Senior Cruiser
Join Date: Dec 2003
Location: Marlborough Sounds. New Zealand
Boat: Hartley Tahitian 45ft. Leisure Lady
Posts: 8,038
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Roverhi,... I have been doing some homework for you, in regards to your very important question on "how do you make new cement stick to old"? OK... there are two important aspects to this. First is in further reply to your "concrete path" description. It's important to remember that you aren't dealing with 'concrete' as such as found in a path. The reason why old and new concrete will not join well, is because the main medium in 'concrete' is the stones. The cement is bonding the stones together and as there is not a lot of cement in the concrete mix ratio, cement will not or can not bond to itself very well. Thus a concrete slab will crack at a join. The cement mix in boat construction is a different story. The cement is of very proportion to the sand mix. The cement over time will indeed continue to chemicaly bond together as it cures.
But here is the important point No.2 in a repair. PVA is used as a bonding agent. Yep, that is simple white wood glue. The old cement edge is kept wet with water and the PVA as the new cement is applied. Small repairs can have the PVA mixed into the cement mix as well. The finished result is a strong water tight bond that continues to get stronger with future curing. One such repair done on a local boat here, was surveyed about 10yrs later and no one could find were the repair was carried out.
__________________
Wheels
For God so loved the world..........He didn't send a committee.
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07-01-2006, 13:03
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#100
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Registered User
Join Date: Sep 2005
Location: Phoenix, Arizona... USA
Posts: 2,386
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Hey Wheels.
Whats up with the mulitple "Posts," of the same thing?
I'd just thought I'd let you know that !!
__________________
CaptainK
BMYC
"Those who desire to give up Freedom in order to gain security, will not have, nor do they deserve, either one." - Benjamin Franklin
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07-01-2006, 14:44
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#101
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Senior Cruiser
Join Date: Dec 2003
Location: Marlborough Sounds. New Zealand
Boat: Hartley Tahitian 45ft. Leisure Lady
Posts: 8,038
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Yeah sorry for that. My connection has been slow this morning and as I hit submit, my line kicked me off. I dialed up and waited and the double post appeared.
__________________
Wheels
For God so loved the world..........He didn't send a committee.
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15-01-2006, 15:31
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#102
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Registered User
Join Date: Jan 2006
Location: Ireland
Boat: yes
Posts: 5
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Has anybody here ever actually built a ferro hull.
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15-01-2006, 19:37
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#103
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Senior Cruiser
Join Date: Dec 2003
Location: Marlborough Sounds. New Zealand
Boat: Hartley Tahitian 45ft. Leisure Lady
Posts: 8,038
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There are at least two here that I know of. Chris and Greg. I believe Greg has built a few and maybe still on a current project, a 37-38ft Hartely Tahitian I think it was.
Any particular question you have???
__________________
Wheels
For God so loved the world..........He didn't send a committee.
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15-01-2006, 22:39
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#104
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Registered User
Join Date: Sep 2003
Location: gippsland/australia
Posts: 133
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ferro hulls
Yes i have built a ferro hull it is now over 20years old and the hull still looks the same as when i first splashed her. Not current project a 38 ft hartley tahitian (south seas),as it was a bare hull built by the boat builders bennets who built many of them here.And i am nearing completion rigging the masts at the moment,a bit of wiring and paint the outside,splash in march i hope.Greg
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16-01-2006, 09:41
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#105
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Registered User
Join Date: Jan 2006
Location: Ireland
Boat: yes
Posts: 5
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Hi guys.
I want to start a 35' er this summer .I would just like to be in touch with someone who's done it before and pick their brains on occasion.One question that springs to mind is the hex wire vs.
weld mesh debate and another would be how many people am I likely to need on the big day(this is definately gonna be a one shot hull).I'll be aiming for a thickness of 5/8" to 3/4".The only ferro in the boat will be the hull.How many 40hr weeks do you think it will take two very competent tradesmen(one carpenter,one welder) to complete the armature,including mesh, ready for casting,assuming that the boat has already been lofted.Ballpark figure.
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