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26-02-2010, 11:06
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#46
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Senior Cruiser
Join Date: Dec 2008
Location: Between Caribbean and Canada
Boat: Murray 33-Chouette & Pape Steelmaid-44-Safara-both steel cutters
Posts: 8,508
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Quote:
Originally Posted by JHook
A steel hull has to be kept 100% covered with paint at all times - inside and out. It's a constant battle against rust. Aluminum will last longer than I will without a drop of paint. .
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True - provided you don't get corrosion problems and you use the correct grade of aluminum.
I went to look at an aluminum boat last month, saw a dab of corrosion, poked with my knife and OOOOOPSie! Almost lost knife.
I know you know that, but others may not. We tend to say "aluminum" or "alloy" as if it we all of one type. Not true.
That is about the extent of my knowledge on the matter.
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26-02-2010, 11:12
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#47
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Senior Cruiser
Join Date: Dec 2008
Location: Between Caribbean and Canada
Boat: Murray 33-Chouette & Pape Steelmaid-44-Safara-both steel cutters
Posts: 8,508
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This is a topic pretty near to our hearts.
We have one steel boat, pretty simple.
For various reasons we just got another, bigger and more complicated, but still pretty simple.
On the other hand the two with the most experience at this I can think of are the Pardees with two wood boats and Anne Hill with a wood/glass composite boat.
I would highly recommend Voyaging on a Small Income to anyone seriously considering this concept. Lots of really good ideas there. No motor for many years (finally succumbed to a free Ducati air cooled diesel) no water tanks (lots of small containers) various heat sources, junk rig for simplicity, vegetarian diet much of the time.
In my opinion Anne's book is much more practical than Fitzgerald's, even though Sea Steading spoke to my heart more directly. Both are good reads.
Apparently Anne and Peter have split but she is still cruising, now on a steel boat, a Wylo IIRC.
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27-02-2010, 01:36
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#48
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Registered User
Join Date: Aug 2009
Location: central Florida
Boat: 16 ft kayak :-P
Posts: 2
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JHook, that boat is beautiful! i like the unpainted aluminum idea . with regards to not having a motor, what do you think about mounting some oars?
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27-02-2010, 06:21
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#49
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Registered User
Join Date: Aug 2009
Location: between the devil and the deep blue sea
Boat: a sailing boat
Posts: 20,420
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I cannot agree with the 'constant battle against rust' (on steel hulls). Actually, if the boatyard job was done right, there is very little maintenance, and, in any case, there is NO battle.
A poorly primed and painted hull will call for a lot of maintenance, but this is not steel-related.
b.
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27-02-2010, 08:23
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#50
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Registered User
Join Date: May 2008
Location: We're technically refugees from our home in Yemen now living in Lebenon
Boat: 1978 CT48
Posts: 5,964
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So lets say you want to insulate the hell out of that steel hull...eveywhere.
Is it the "cold tar" or what ever its called then spray PU foam every where...is that it, could you be sure nothing is happening inside....for ever and ever!
Lets say we have a dry bilge or some other bilge liner over the foam...so the foam stays dry always.
I'm trying to decide on the hull material for my ultimate autonomous boat and I keep thinking steel...but the insulation is a critical component....seems like 4in of PU would also give an added measure of collision saftey.....fixing a hole may be a bit of a pain.
__________________
James
S/V Arctic Lady
I love my boat, I can't afford not to!
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27-02-2010, 09:28
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#51
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Registered User
Join Date: Mar 2009
Location: Homer, AK is my home port
Boat: Skookum 53'
Posts: 4,042
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There are some new epoxy type coatings out there that might serve well on a steel hull. I have worked on steel hulled vessels for years (not yachts but work boats) and I have seen rot not unlike that on a wooden boat, at the 30 year mark they get labor intensive, I saw one steel yacht in the south pacific that did not have running rust on the hull, but the owner went over the hull every morning, sanded & painted any suspicious looking spots. I am not saying that is what is needed to maintain a steel boat, they do require a good bit of attention. I own a 1961 aluminum commercial fishing boat that the hull is unpainted and it has been used and abused by the P.Os. and she is still in fairly good shape, there is some pits in the fish hold but that comes from the dissimilar metal problems. The biggest watch out for aluminum vessels is insuring that non of your wires can ground out on the vessel, and watching your dissimilar metal combination to prevent galvanic corrosion. There is also the noise issue, you can hear every little wavelet that slaps the hull. I have been told that the spray in bed liner for pickups works well for sound deadening and protection, I have not seen it first hand though. There is also the sweating issue with metal boats that can be solved with spray foam. I have an affinity for old boats, be they glass, alum., steel, or wood, none are maintenance free, and they all require some outside help from time to time. It all depends on which elements you are most comfortable working in.
__________________
" Wisdom; is your reward for surviving your mistakes"
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27-02-2010, 09:38
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#52
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Registered User
Join Date: May 2008
Location: Sweden
Boat: Between boats
Posts: 474
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Quote:
Originally Posted by James S
So lets say you want to insulate the hell out of that steel hull...eveywhere.
Is it the "cold tar" or what ever its called then spray PU foam every where...is that it, could you be sure nothing is happening inside....for ever and ever!
Lets say we have a dry bilge or some other bilge liner over the foam...so the foam stays dry always.
I'm trying to decide on the hull material for my ultimate autonomous boat and I keep thinking steel...but the insulation is a critical component....seems like 4in of PU would also give an added measure of collision saftey.....fixing a hole may be a bit of a pain.
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If I were to build a one off, adjusted for my needs, I'd use strip planking, covered with epoxy and glass.
Boatbuilding Methods: strip planking
/Hampus
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27-02-2010, 10:02
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#53
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Registered User
Join Date: May 2008
Location: We're technically refugees from our home in Yemen now living in Lebenon
Boat: 1978 CT48
Posts: 5,964
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Thats a pretty interesting method.
So far, my dream boat is 30m long with two out riggers of undetermined length but around 10m.
The outriggers probably want to be as light as possible..but the main hull could be wood...if so I'd be more inclined to go cold molded....the advantage to steel for me is the cost, strength, and ease of repairing anywhere (the PU foam would complicate that)
The big question is if modern coatings/techniques can insure isolation.
__________________
James
S/V Arctic Lady
I love my boat, I can't afford not to!
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27-02-2010, 11:23
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#54
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Senior Cruiser
Join Date: Dec 2008
Location: Between Caribbean and Canada
Boat: Murray 33-Chouette & Pape Steelmaid-44-Safara-both steel cutters
Posts: 8,508
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If you have 3 gazillion dollars you could build in monel.
Steel with a couple of inches of foam to the waterline is what I have on my 33' boat.
The interior hull had coal tar epoxy but that started to come up a couple of years ago. Don't know why and it is giving me some fits.
I am using Ameron zink epoxy with an Ameron top coat from C.G. Edwards. I think that is working fine.
Then there is the fellow who is building a Colin Archer (I think?) out of lapstrake aluminum, so just about anything can be done.
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27-02-2010, 13:38
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#55
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Registered User
Join Date: Mar 2009
Location: Homer, AK is my home port
Boat: Skookum 53'
Posts: 4,042
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I think for all around ease and longevity, I would go with systems 3 epoxy and glass cloth over plywood, I have built hatch covers out of it and long after the boat had been destroyed the hatch covers were still around acting as pallets for my commercial fishing supplies on swampy ground and they held up well for years, no de-lamination or water incursion evident. With the new methods of vacuum bagging you could just about guarantee complete saturation, and the epoxy is easy work with should you want to add shelves or repair holes, or what ever. Maybe a Wharram cat. with the above construction methods, would be an ideal combination. I think that could be very worry free for a long time.
__________________
" Wisdom; is your reward for surviving your mistakes"
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27-02-2010, 13:55
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#56
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Registered User
Join Date: May 2008
Location: Sweden
Boat: Between boats
Posts: 474
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I recently read an article, I think by yacht designer Tom MacNaughton, about epoxy and glass over wood. I don't remember what method for construction they used but the end result produced a boat capable of taking the same kind of neglect a GRP boat would. I thought it was very interesting and a great way for producing hulls in small series. I spent 15 minutes trying to find the article again, but no luck
/Hampus
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27-02-2010, 14:38
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#57
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Registered User
Join Date: Mar 2009
Location: Homer, AK is my home port
Boat: Skookum 53'
Posts: 4,042
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We have a local skiff builder that uses systems 3 and fiberglass cloth on the bottom for friction resistance and his skiffs are famous here for their longivity and strength.
__________________
" Wisdom; is your reward for surviving your mistakes"
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28-02-2010, 00:57
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#58
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Registered User
Join Date: Feb 2010
Posts: 10
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Quote:
Originally Posted by floridanomaly
JHook, that boat is beautiful! i like the unpainted aluminum idea . with regards to not having a motor, what do you think about mounting some oars?
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Perhaps a single sculling oar of the type used on Chinese junks would be practical. I'm looking into it. Some of those Chinese junks are massive. (The boat S/V Macha uses this method. The Adventures of Sailing Vessel Macha)
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28-02-2010, 01:06
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#59
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Registered User
Join Date: Feb 2010
Posts: 10
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Quote:
Originally Posted by hpeer
True - provided you don't get corrosion problems and you use the correct grade of aluminum.
I went to look at an aluminum boat last month, saw a dab of corrosion, poked with my knife and OOOOOPSie! Almost lost knife.
I know you know that, but others may not. We tend to say "aluminum" or "alloy" as if it we all of one type. Not true.
That is about the extent of my knowledge on the matter.
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Yeah. You have to use 5083-type aluminum, plenty of zinc anodes, and an electrical system isolated from the hull. Galvanic corrosion is definitely something that can happen. My hull would have 10mm thick plates below the waterline.
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28-02-2010, 01:11
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#60
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Registered User
Join Date: Feb 2010
Posts: 10
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Quote:
Originally Posted by barnakiel
I cannot agree with the 'constant battle against rust' (on steel hulls). Actually, if the boatyard job was done right, there is very little maintenance, and, in any case, there is NO battle.
A poorly primed and painted hull will call for a lot of maintenance, but this is not steel-related.
b.
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Well, if the paint is scratched or chipped immediate attention is required. The same would be true for aluminum except you don't need to paint aluminum. 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.
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