Hull material

[salient]

Wood. If God had wanted us to have fibreglass boats, he would have made fibreglass trees. Was the Ark GRP? I don't think so.

And as for steel or aluminium, the cost in carbon footprint is unconscionable in this enlightened age. Besides, if you ask me, you are sorely tempting fate to go to sea in a vessel made of anything that doesn't float.

Beautiful, natural, resilient and renewable wood. Accept no substitutes.

[Stranded Mariner]

Originally Posted by salient

If God had wanted us to have fibreglass boats, he would have made fibreglass trees.

There are fiberglass trees in Beijing now to make it look nice for the Olympics. The real ones they planted at first, died within months because of the pollution.... This is not a joke.

[Robertcateran]

Originally Posted by Alan Wheeler

And the composites make for extrememly light weight boats designed for speed.
Hmmm, I wonder if anyone ever attempted an FC cat or Tri. Yikes that would be scary.

I saw such a beast when I was in PNG. It had about 6:1 hulls and was nicknamed the ark. I don't know if it ever got finished. Looked sound enough. There are also lots of catamaran steel barges.
Robert

[Robertcateran]

I own a plywood cat over 20years old with no sign of rot. I have built a small almost bullet proof aluminium tri and sailed it from PNG to Australia, My own preference now is polypropylene honeycomb with d/bias fibreglass and epoxy resin vacuumed. This is because of the resilience of the material, its light weight, small carbon footprint compared to solidified electricity (aluminium), price, low maintenance, sound and energy absorbance. It is also stif enough and doesn't absorb water. I am also partial to strip plank for its ease in producing nice shapes
I had no trouble with fairing compound and paint sticking to aluminium, but I was pretty careful in preparation and was anal about electrolysis. I have experienced boats that got electrolysis problems from contact with the carbon black in black rubber products such as tyres as fenders and shock-absorbing foams.
Robert

[cooper]

I dont doubt that steel boats have a larger carbon "footprint"...but I sure would like to see the numbers !!!! Glass manufacture is very energy intensive, and epoxy and similar products are usually from oil. Then there is all the stuff that we put into them which (as anyone who has built a boat well knows) is far more than just the hull. I am an avid greeny so someone give me some real numbers of real comparisons.

[Robertcateran]

Agreed. glass is fairly energy intensive, but there is not much of it in a cored boat- about 200kg on the boat I am interested in. Epoxy and polyprop core are made from oil products, but unless you burn it, they are not producing CO2. The core is mostly holes. . Steel is pretty hungry as the carbon from coal or charcoal is needed to strip the oxygen from the iron ore, as well as providing heat. There is a lot more weight in steel and the plates don't have a core to give them stiffness.
I don't have the figures immediately, but I have seen them, and the manufacture of steel really does produce a lot of co2. I recall aluminium as even worse if the electricity is derived from fossil fuels, but stuff all if not derived from fossil fuels. It is certainly worth checking the whole of life production of CO2 in our addiction to messing about in boats. It probably can't be justified with the need to reduce our carbon footprint, but I will probably put my head in the sand until I am forced to confront it.

Robert

[noelex 77]

No material is perfect but aluminum got my vote. I have to disagree with the comments that an aluminum boat is always noisy. My boat has 2 inches of foam It gets no condensation and associated mold in conditions where fiberglass boat owners are scrubbing there ceilings with vinegar. It is also very quiet. I have to leave noise makers outside at night (such as a loose halyard ) otherwise the wind can increase dramitically without any increse in noise inside to act as a warning.

[GordMay]

Originally Posted by noelex 77

... My boat has 2 inches of foam It gets no condensation and associated mold in conditions where fiberglass boat owners are scrubbing there ceilings with vinegar. It is also very quiet ...

Apples & oranges:
I’d expect a hull, of any material, with 2" of foam to be significantly drier and quieter than any hull without insulation.
The point others may have been making, is that an aluminum hull often requires insulation, to remain dry (in many circumstances) and quiet.

[noelex 77]

I dont think I was comparing apples to oranges. Most metal cruising boats are insulated particuarly aluminum as they tend to be more expensive. Very few fiberglass boats have any additional insulation.
To compare an average aluminum yacht with an average fiberglass yacht (apples & apples) you need to compare an insulated aluminum yacht with an uninsulated fiberglass yacht. The extent and thickness of insulation does vary so an aluminum yacht can be noisier or quieter than a fiberglass boat, but noise concerns should not put you off aluminum yachts in general.
You are correct in saying an "aluminum hull often requires insulation, to remain dry (in many circumstances) and quiet", but insulation is common practice.

[Steve Pope]

Naturally I am Biased, Aluminium does it for me, Allan re movement making you feel ill would have to be a design issue rather than the material the boat is built of, my Trismus has a high initial stability, normal for a centreboard yacht and doesn't sail as badly at anchor as many of the Gulf cruiser racer types that abound up here in the North. Noise wise I have 40mm sheet insulation from the waterline up and the slip slop of the sea at anchor is no worse and in many cases better than many of the other glass / cold moulded /steel yachts I have sailed on. Once again the noise is relative to the design, the flatter the run aft the more slip slop noise. And as this seems to be the current thinking in modern design concepts at present it is something that is a trade off speed = noise at anchor.

[MidLandOne]

Just a couple of points from my own experience on some things raised -

Insulation of metal boats - should be regarded as just part of the requirements of building them, I cannot imagine a metal cruising yacht built without insulation as it will be like a drum (and I would insulate a frp cruising boat for myself too if not foam sandwich). Flexible closed cell insulation sheets glued onto the plating is widely used in superyachts (eg Armourflex, Korex) and 1 inch of that will result in a boat quieter than other constructions. Our own steel yacht with 1 inch of Korex was quieter than the builder's own timber composite yacht and I also stand by Noelex 77's comments related to not being able to hear things outside the boat or, indeed, the other way around. We do hear water "sloshing sounds" when sailing but only from our own water tanks - such boats can be uncannily quiet.

A comment was made about the failure of aluminium on high speed ferries (which I have managed the design and construction of). This is not a fault of the aluminium as a material but rather of the need for light scantlings in such vessels so that the boat will perform. While these vessels are mostly built to be in class there is considerable difference in the scantling sizes allowed between the major classification societies eg a boat designed to DNV rules will be considerably lighter than one built to Lloyds. But in the end, the striving for low displacement to enable these vessels to be fast and still stay a modicomly frugal in fuel use is the problem rather than the material (I've known of big fast ferries that are dived on weekly in order to check for cracks in the plating). No other economic material would allow them to be built to such light weight budgets.

Painting of aluminium has been mentioned as a problem. Painting aluminium is not a problem these days. In the past (maybe 15 years or more ago) there were difficulties with poor marine alloys and a poorly designed more modern boat may have difficulties in some areas - if the paint won't stick then something is wrong with the paint or the alloy. The preparation I see now on aluminium boats is generally simple coarse sanding of the alloy plating followed by application of an epoxy primer, followed later by fairing and build coats, then polyurethane topcoats. Only one example - I have an aluminium commercial vessel which is more than just a few years old parked next to me and there is no white powder to be seen anywhere on it, neither on the painted parts or the unpainted parts (whether unpainted intentionally eg rails, or unintentionally due to accident).

Fairing has been mentioned as falling off. I have not heard of this myself for decades. In the good old days fairing was done with polyester, which was a problem in that way. For decades fairing has been done with epoxy incorporating fillers and have never known of any problem with it falling off, although like anything a bad job is a bad job and may lead to problems.

Note that my making these comments should not be just assumed as my being married to steel or aluminium - I did say earlier that my first choice would be a very expensive exotic laminate construction .

Lastly, has been mentioned that steel and aluminium are environmentally unfriendly from a carbon footprint point of view. Putting aside comparisons with other materials, I expect that in the end one's view depends as to whether one is a watermelon or not ("watermelon" - green on the outside and red to the core ).

[BigCat]

Fiberglass boats don't need insulation, as fiberglass isn't nearly as conductive as metal. Also, some fiberglass boats have foam or balsa core, which adds to the "r" factor. An added benefit here is that you don't need the weight and expense of a ceiling, if you use the right construction techniques (vacuum bagging,) resulting in a smooth fiberglass surface inside as well as outside of the boat. Ceilings are expensive, heavy, and take up a lot of room. Too much room, on a multihull.

[imagine2frolic]

Minisailor,

I am bit partial to cold molded also. If I look around I think I can find a lovely example of one too.........LOLOLOLOLOL....HEY WHAT DO YOU KNOW I FOUND 2 PICS

[BigCat]

"I am bit partial to cold molded also." The usual comments are "very light" "labor intensive" and "hard to repair."

[Fábio Fonseca]

Hello saylors, i am brasilian and i live near the Tietê river in Brasil and my dream is make myself my own sail boat. Maybe you can show me how and if is possible to do my future. Sorry for my bad inglish, Fábio.