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Old 28-02-2010, 08:25   #61
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On the other hand steel is probably the best protection against grounding and other impacts and it can be easily repaired in ports all over the world, unlike aluminum.
Why do you say that? I think that today aluminium welders and manufacturing is everywhere, I have never been in a place that didn't have it. The question might be if they have the right type of aluminium in stock but I think every aluminium boat carries a piece for emergencies. Also, you can bring a thinner piece and epoxy it in place for emergency patch, even under water.
Boats that really want to be autonomous carry their own welding equipment and did the courses regardless of choice of metal.

I would never choose steel (done that for 17 years and the maintenance is still fresh in my head 30 years later) but I would definitely go for aluminium.

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Old 28-02-2010, 11:15   #62
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Damn it JHook, now you have blown my Sunday afternoon. I didn't know of this site. I was just rereading part of Sea Steading last night because some of it touched me so. Now I gotta go look at this.

Do you know what Fitzgerald is up to these days?

Also, I think the Pardees tried the long Junk oar thing but gave it up as they couldn't get the curves correct.
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Old 28-02-2010, 12:16   #63
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Why do you say that? I think that today aluminium welders and manufacturing is everywhere....
It takes alot of talent to shape and weld aluminum, unlike steel which can be competently welded in any third world marina. Heat bending or "plemishing" weakens aluminum, and shaping metal without heat requires special and expensive tools and alot of skill and experience. You can't just hire anyone and expect to get a quality job that doesn't need to be faired and painted. Not an easy task. I know of many peope who've gone through numerous welders in the US before finding one who was actually qialified to do the job, suffering many botched welds and repairs before the boat was even launched. Even well respected boatbuilders who "specialize" in aluminum have to be watched like a hawk.

You can glue aluminum with Plexus but how long it will hold is anyone's guess. Plexus won't say.
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Old 28-02-2010, 12:36   #64
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Damn it JHook, now you have blown my Sunday afternoon. I didn't know of this site. I was just rereading part of Sea Steading last night because some of it touched me so. Now I gotta go look at this.

Do you know what Fitzgerald is up to these days?

Also, I think the Pardees tried the long Junk oar thing but gave it up as they couldn't get the curves correct.
Here's another good link, if you haven't already found it.

Knockabout Sloops: Engineless Sailing

I believe Fitgerald went the other extreme to a large, lightweight, high performance sloop. Can't remember the make and model. And now he's looking to build a big Wharram catamaran.
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Old 28-02-2010, 13:03   #65
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Originally Posted by JHook View Post
Here's another good link, if you haven't already found it.

Knockabout Sloops: Engineless Sailing

I believe Fitgerald went the other extreme to a large, lightweight, high performance sloop. Can't remember the make and model. And now he's looking to build a big Wharram catamaran.
Jay moved to the Big Island of Hawaii. I'm quite sure he never bought anything after Macha, but he has expressed a lot of interest in a big Wharram cat. Here's his blog, which will catch you up with what he's doing these days:

Sensible Simplicity
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Old 28-02-2010, 19:49   #66
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It takes alot of talent to shape and weld aluminum, unlike steel which can be competently welded in any third world marina. Heat bending or "plemishing" weakens aluminum, and shaping metal without heat requires special and expensive tools and alot of skill and experience. You can't just hire anyone and expect to get a quality job that doesn't need to be faired and painted. Not an easy task. I know of many peope who've gone through numerous welders in the US before finding one who was actually qialified to do the job, suffering many botched welds and repairs before the boat was even launched. Even well respected boatbuilders who "specialize" in aluminum have to be watched like a hawk.

You can glue aluminum with Plexus but how long it will hold is anyone's guess. Plexus won't say.
I didn't mean building a complete hull.... I wouldn't even do that in the USA! But I have seen excellent aluminium manufacturing in all the 3rd world countries we've been and in some cases couldn't find a decent stainless steel welder while I could find one for aluminium. I am talking about repairs, radar posts & arches, towers on fishing boats etc. etc.

When you're holed on a reef, I don't think you care much about what Plexus or others say, you just want to close the hull and get yourself to a haul-out for repairs. Jedi is plastic and I never went up a reef but what I have heard is that with aluminium they just slab the patch on with "under water" rated epoxy, pump out & dry the repair on the inside, drill holes from the inside and put blind rivets in and seal those again from the outside with sealant or duct tape or whatever is at hand and sticks. They manage to get to a haul-out that way.

Also, if you find yourself in a yard with a hole in your aluminium boat and you can't weld it yourself and there is no one there who can weld it, you can fly someone in who can and your problem is solved. It is getting to that haul-out that makes the difference.

I like aluminium boats and I like wood-epoxy composite boats and sometimes wonder why I am on a plastic (well, fiberglass/vinylester) boat.

ciao!
Nick.
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Old 28-02-2010, 22:08   #67
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Fiberglass can be repaired with epoxy as well, and splash zone works very well underwater. If I had the patience, I think I would have went with the epoxy encapsulated wood, it doesn't take much room to carry a few bits of plywood, & some epoxy, if one needed to effect repairs.
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Old 01-03-2010, 04:00   #68
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I didn't mean building a complete hull.... I wouldn't even do that in the USA! But I have seen excellent aluminium manufacturing in all the 3rd world countries we've been and in some cases couldn't find a decent stainless steel welder while I could find one for aluminium. I am talking about repairs, radar posts & arches, towers on fishing boats etc. etc.

When you're holed on a reef, I don't think you care much about what Plexus or others say, you just want to close the hull and get yourself to a haul-out for repairs. Jedi is plastic and I never went up a reef but what I have heard is that with aluminium they just slab the patch on with "under water" rated epoxy, pump out & dry the repair on the inside, drill holes from the inside and put blind rivets in and seal those again from the outside with sealant or duct tape or whatever is at hand and sticks. They manage to get to a haul-out that way.

Also, if you find yourself in a yard with a hole in your aluminium boat and you can't weld it yourself and there is no one there who can weld it, you can fly someone in who can and your problem is solved. It is getting to that haul-out that makes the difference.

I like aluminium boats and I like wood-epoxy composite boats and sometimes wonder why I am on a plastic (well, fiberglass/vinylester) boat.

ciao!
Nick.
I would think flying someone into a remote area is going to be a bit rich for most cruisers blood, sure would be mine. Besides, isn't that a bit contrary to the idea of being "autonomous"?
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Old 01-03-2010, 05:04   #69
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I would think flying someone into a remote area is going to be a bit rich for most cruisers blood, sure would be mine. Besides, isn't that a bit contrary to the idea of being "autonomous"?
True!

Regardless of what material you choose for hull, rig etc, having the materail and knowledge needed to carry out repairs is essential. If you want to be autonomous that is.

I like where this thread is going

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Old 01-03-2010, 05:55   #70
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If you were down in Australia, you could get the welding done no sweat, they have great craftsmen there. The idea with autonomous living is being able to effect most of your own repairs, gather & store your own food, provide your own entertainment. We'll be making Smores and singing Kumbya, down by the garbage pit fire later, so bring your guitar and homemade chocolate, & marshmallows. Polynesians hand make a nifty little ukulele type critter and use fishing line for the strings and you can get a passable song with it, I even heard one guy playing 60's rock on one.
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Old 01-03-2010, 08:28   #71
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I would think flying someone into a remote area is going to be a bit rich for most cruisers blood, sure would be mine. Besides, isn't that a bit contrary to the idea of being "autonomous"?
On cost... one just saved his holed boat from a reef; time for joy, not complaining about cost of a plain ticket..

On autonomous: indeed, the circle is closed because this is what I wrote earlier in this thread:
Quote:
Boats that really want to be autonomous carry their own welding equipment and did the courses regardless of choice of metal.
and I was serious about that. All the serious autonomous cruisers I've met on aluminium boats have that miniature aluminium welding machine and did those courses and can do the repair themselves.

It was JHook who wrote that aluminium was inferior compared to steel incl. the "fact" that in far off places no aluminium welders are available. I merely countered that because the 3rd world I've seen does have these people available. I have sailed a steel boat for 17 years and it is a hell of a job to keep it up. More than 50% of the steel boats we meet are severely corroded to the point I would call them unfit to live on.
When you compare steel to aluminium for a hull that's up on a reef, IMO the advantage that the steel hull has over an aluminium one is way too small compared to the maintenance gap between the two metals and aluminium is by far the overall winner for a cruising sailboat. Even the higher cost of building an aluminium hull is easily overcome by the lower maintenance costs after launch.

When compared to plastics or wood-epoxy composites: sure, these are as easy to repair, if not easier. The problem is that they are holed much quicker than metal. The reason is that metal gives way without being punctured. I have seen aluminium hulls (but steel is the same) that were salvaged from a reef and they were dented fore to aft but not holed. A plastic or wood/epoxy boat will not be that lucky. Same goes for collisions. In the end, it's always a compromise but the question is which material comes out on top of the others.

cheers,
Nick.
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Old 01-03-2010, 09:19   #72
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So if we go with aluminum on our dream autonomies boat, how do we insulate...if its PU foam, then welding repairs become problematic.
what other type of insulation would stop condensation from forming?
I was wondering about Cold molded wood for the hull and aluminum for everything top sides...is that ever done?
Seems that cold molded could also include a layer of carbon fiber or Kevlar to help prevent puncture?
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Old 01-03-2010, 09:30   #73
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I think spraying the complete inside of the hull with at least 2" of PU foam is the only way to go. If welding is needed (most hulls will never need it), it will have to removed in that area and new foam applied after repairs are done.

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Old 01-03-2010, 15:48   #74
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The coral reef resistant benefits of a metallic hull are undeniable. But... A cold molded hull will have pretty much all the insulation it needs just from the way it's built. One could always go to 3/4" planks instead of 1/2". You could also leave large portions of the inside of the hull bare without liner and still have it look nice in a cold molded boat. Who would want to look at PU foam all day? Easy access to the inside of the hull would be important. Especially if the hull is more prone to be penetrated by a container. In an emergency, the hull could be temporarily repaired by a sheet of plywood and a few screws, or even hammer and nails, at least enough to keep the leak under control. Cutting away damaged planks and scarf in new pieces can ba done by most wood workers, it's not rocket science. Wood is cheap and quite easy to come by in one form or the other. GPR work can be done by most yacht men.

Darn it... I've almost convinced myself that I need a cold molded strip planked hull

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Old 01-03-2010, 16:01   #75
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For metal boats you must just see the foam insulation as part of the job. It's much more effective than wood planks of course, no matter how thick the planks are... just compare R-values.

I must admit that I am not a fan of cold molded strip planked hulls. I think that evolution of boat building techniques have brought better methods, also for DIY building.

My favorite is the wood-epoxy-glass composite, using either veneers or thin plywood strips and finishing with glass. Also, Kevlar could be used for protecting the turn of the bilge, greatly increasing the abrasion resistance.

Jedi is cored with 1" balsa everywhere and that provides a decent insulation too. We have extra fiberglass on the turn of the bilge but never had to test it's effectiveness....

cheers,
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