I may have the rarest skiff..........

Discussion in 'Boat Design' started by Homarus, May 22, 2009.

  1. Homarus
    Joined: May 2009
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    Location: Matinicus island, maine

    Homarus New Member

    When i was younger I moved to Maine and was awed by all the awesome lobsterboats zooming around in my small fishing community. My Father recieved a small skiff from his Dad that sat around for years in his dooryard in Rhode Island. We never used it, and it sits in our yard to this day..
    It's a stainless steel skiff that was built in the 40's with really good metal, as it doesn't have the slightest bit of tarnish. I've looked and researched but I have no clue who made it or where. if I recall correctly I remember my grandfather saying it was a sears model. My research doesn't prove this or disprove it, there's no info on it at all. It seems to have come out of some type of mold as it looks like the steel was stamped to form the craft, and it has very nice clean lines. The wood was all rotted (seats) so my dad redid them with oak, and added a 1.5 inch thick piece of mahogany for inside the stern to bolt on the outboard, there was wood there before but it was long gone. I'd say it is around 14-16 gauge stainless by the looks of it, and it is extremely light. I don't know who/what or when it was made so I can't put a value on it but I know the metal is of great quality. Could anyone add some info into where/who could have built it and what it's worth might be? I grew up around boats for over 20 years now and I have never seen or heard anything about one....
     
  2. PAR
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    PAR Yacht Designer/Builder

    If it's stainless, it wouldn't be "extremely light", particularly compared to a well built lapstrake or aluminum boat of similar dimensions.

    Photos would be very helpful. In the first half of the 40's, stainless would have been very expensive with the war effort on. It wouldn't have been much cheaper after the war, but certainly more readily available.
     
  3. Homarus
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    Homarus New Member

    It is lighter cause it doesnt require as thick a material as a lapstrake or even aluminum, it's about the thickness of a penny
     
  4. NEWENGLAND

    NEWENGLAND Guest

    Maniacs

    Only a wealth Maniac would have built a Stainless Steel Skiff. Maybe someane at the Bath Shipyard with some extra time on there hands?

    Put up some pictures.


    I had a Welded/Rivited Steel skiff many years ago. Gave iot to a buddy who left it on his mooring of course it sunk and its still in the mud in Salem Harbor.




    [​IMG]
     
  5. lewisboats
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    lewisboats Obsessed Member

    I would lay you odds it ain't stainless...not if it is light. It is probably polished aluminum. I work with 16 ga stainless all the time and a 4x8 ft sheet is a bear to lift.
     
  6. alan white
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    alan white Senior Member

    Yeah, stainless would be heavy. A stainless skiff would be a freak. It's hard to describe what visual and tactile clues tell you it's one or the other, except aluminum is so much softer that you can cut into it a bit with a chisel. Stainless is hard enough that the chisel would just skitter across the surface.
    Your boat is aluminum, or you are really strong.
     
  7. gonzo
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    gonzo Senior Member

    The quick & dirty test is to use a sharp awl or knife and scratch the metal. It will leave a mark on aluminum.
     
  8. NEWENGLAND

    NEWENGLAND Guest

    [​IMG]tESTING Testing.

    Just shoot it with a regular old .22 soft 30 grain. If it bounces off its stainless. If it makes a hoe its Alum. Simple eh?

    or you can lick it withyour tounge in the dead of winter. If it sticks its Stainless.
     
  9. gonzo
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    gonzo Senior Member

    The .22 I agree, however your tongue will stick to any metal
     
  10. lewisboats
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    lewisboats Obsessed Member

    Wouldn't be prudent....either method...The scratch test is by far the better bet. A cheap knife will definitely scratch aluminum but probably not do more than give the illusion of a scratch on real stainless.
     
  11. PAR
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    PAR Yacht Designer/Builder

    T-6, 14 gauge aluminum (.0508") will weigh about 23 pounds a 4x8 sheet. The same gauge (.0625") 4x8 sheet in stainless (300 series) will weigh 84 pounds. Even if it was the same thickness (which it's not) the stainless would weigh 68 pounds.

    A simple check would be to "mic" the skin thickness. 16 gauge aluminum is .0508", stainless is .0625". 14 gauge aluminum is .0641", stainless is .0781". 12 gauge aluminum is .0808", stainless is .1094".

    Another method would be to calculate the surface area of the hull in square feet then get a reasonably accurate weight. The thickness of a penny suggests it's not stainless, by a long shot.
     
  12. plebusmaximus
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    plebusmaximus Junior Member

    A magnet?

    Is it sanded finish aluminium with a lacquer finish?

    Aluminium rocks! :)
     
  13. alan white
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    alan white Senior Member

    No, a magnet wouldn't be attracted to stainless steel unless it was the type of stainless that has iron in it, which is generally a 400 series. 400 series would have rusted long ago.
    You have an aluminum, boat. It's aluminum. Aluminum.
     
  14. Luckless
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    Luckless Senior Member

    If a stainless Steel doesn't contain iron, then it is not a steel.
     

  15. lewisboats
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    lewisboats Obsessed Member

    More iron.
    300 series stainless contains Iron but there is enough chromium in it to prevent the Iron from rusting by getting a coating of chromium oxide on it and barring the interaction of iron and oxygen. Nickel is added which helps with the corrosion resistance. That also reduces the magnetism to virtually 0. It is still a steel.

    This is from Wikipaedia (but it IS accurate)

    Types of stainless steel

    There are different types of stainless steels: when nickel is added, for instance, the austenite structure of iron is stabilized. This crystal structure makes such steels non-magnetic and less brittle at low temperatures. For greater hardness and strength, carbon is added. When subjected to adequate heat treatment, these steels are used as razor blades, cutlery, tools, etc.

    Significant quantities of manganese have been used in many stainless steel compositions. Manganese preserves an austenitic structure in the steel as does nickel, but at a lower cost.

    Stainless steels are also classified by their crystalline structure:

    * Austenitic, or 300 series, stainless steels comprise over 70% of total stainless steel production. They contain a maximum of 0.15% carbon, a minimum of 16% chromium and sufficient nickel and/or manganese to retain an austenitic structure at all temperatures from the cryogenic region to the melting point of the alloy. A typical composition of 18% chromium and 10% nickel, commonly known as 18/10 stainless, is often used in flatware. Similarly, 18/0 and 18/8 are also available. Superaustenitic stainless steels, such as alloy AL-6XN and 254SMO, exhibit great resistance to chloride pitting and crevice corrosion due to high molybdenum content (>6%) and nitrogen additions, and the higher nickel content ensures better resistance to stress-corrosion cracking versus the 300 series. The higher alloy content of superaustenitic steels makes them more expensive. Other steels can offer similar performance at lower cost and are preferred in certain applications.[citation needed]

    The low carbon version of the Austenitic Stainless Steel, for example 316L or 304L, are used to avoid corrosion problem caused by welding. The "L" means that the carbon content of the Stainless Steel is below 0.03%, this will reduce the sensitization effect, precipitation of Chromium Carbides at grain boundaries, due to the high temperature produced by welding operation.

    * Ferritic stainless steels are highly corrosion-resistant, but less durable than austenitic grades. They contain between 10.5% and 27% chromium and very little nickel, if any, but some types can contain lead. Most compositions include molybdenum; some, aluminium or titanium. Common ferritic grades include 18Cr-2Mo, 26Cr-1Mo, 29Cr-4Mo, and 29Cr-4Mo-2Ni. These alloys can be degraded by the presence of σ chromium, a intermetallic phase which can precipitate upon welding.

    * Martensitic stainless steels are not as corrosion-resistant as the other two classes but are extremely strong and tough, as well as highly machineable, and can be hardened by heat treatment. Martensitic stainless steel contains chromium (12-14%), molybdenum (0.2-1%), nickel (0-<2%), and carbon (about 0.1-1%) (giving it more hardness but making the material a bit more brittle). It is quenched and magnetic.

    * Precipitation-hardening martensitic stainless steels have corrosion resistance comparable to austenitic varieties, but can be precipitation hardened to even higher strengths than the other martensitic grades. The most common, 17-4PH, uses about 17% chromium and 4% nickel. There is a rising trend in defense budgets to opt for an ultra-high-strength stainless steel when possible in new projects, as it is estimated that 2% of the US GDP is spent dealing with corrosion. The Lockheed-Martin Joint Strike Fighter is the first aircraft to use a precipitation-hardenable stainless steel—Carpenter Custom 465—in its airframe.

    * Duplex stainless steels have a mixed microstructure of austenite and ferrite, the aim being to produce a 50/50 mix, although in commercial alloys, the mix may be 40/60 respectively. Duplex steels have improved strength over austenitic stainless steels and also improved resistance to localised corrosion, particularly pitting, crevice corrosion and stress corrosion cracking. They are characterised by high chromium (19–28%) and molybdenum (up to 5%) and lower nickel contents than austenitic stainless steels. The most used Duplex Stainless Steel are the 2205 (22% Chromium, 5% Nickel) and 2507 (25% Chromium, 7% Nickel); the 2507 is also known as "SuperDuplex" due to its higher corrosion resistance.
     
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