Marine aluminum vs marine steel for ship hull. What to choose?

Discussion in 'Materials' started by Edem, Apr 21, 2021.

?

Marine aluminum or marine steel ?

  1. Aluminum

    8 vote(s)
    80.0%
  2. Steel

    2 vote(s)
    20.0%
  1. JSL
    Joined: Nov 2012
    Posts: 811
    Likes: 64, Points: 28, Legacy Rep: 41
    Location: Delta BC

    JSL Senior Member

    A photo of the Cat mentioned. Does various types of cruises (dinner, wedding, etc) in Vancouver.
     

    Attached Files:

    bajansailor likes this.
  2. bajansailor
    Joined: Oct 2007
    Posts: 3,595
    Likes: 1,560, Points: 113, Legacy Rep: 37
    Location: Barbados

    bajansailor Marine Surveyor

  3. ExileMoon
    Joined: Oct 2009
    Posts: 67
    Likes: 21, Points: 8, Legacy Rep: 45
    Location: Shanghai

    ExileMoon Junior Member

    I used to think that steel and aluminum have their own advantages. But now I have changed my opinion, and now I think there is no need to use steel for boats under 15m. There is no need to use steel even for cost reasons.

    Because of these small but well-equipped yachts, even if aluminum is used, the cost of hull materials only accounts for a small part of the entire yacht construction cost, to be precise, less than 10%. At this time, steel has no significant cost advantage. Only when the ship becomes larger, for example, more than 30m, the cost issue will become prominent. .

    However, if your boat is between 15~30m, then choose steel or aluminum, the choice is a little vacillating.

    Regarding the lack of skills of your welders, I am just as confused as others. This does not seem to be a very difficult problem. Generally, a good welder can basically master it after one week of professional knowledge training in aluminum welding.
    Maybe the argon gas supplied locally is not pure enough?

    In terms of corrosion resistance, aluminum boats have no particular advantages. To use an aluminum boat properly, careful maintenance is indispensable, and a large number of sacrificial anodes need to be replaced every year. This is the same as a steel boat. If these maintenances are not carried out, the aluminum boat will quickly corrode.

    The main problem with steel boats is not the outside but the inside of the hull.

    Condensed water (they are not sea water but fresh water, and aluminum has good resistance to them) is automatically generated inside the hull and gathered in the bilge. On some compact and exquisite yachts, these places are often covered by decoration materials, which makes inspection and maintenance impossible, resulting in catastrophic corrosion. However, those relatively crudely manufactured boats (such as fishing boats), because they have no coverings, are directly exposed and easy to inspect and maintain, they can be used well.

    I noticed that your boat will be used in Seychelles. I don't know the industrial supply situation in Seychelles, but it is estimated that it is difficult for the local area to have the ability to repair aluminum boats. This requires argon gas supply and MIG welding equipment and corresponding skilled workers. I guess Seychelles lacks these.

    In addition, local shipyards and mechanics may also lack good skills in maintaining aluminum boats. They may only know how to maintain steel boats but lack the knowledge of aluminum boats.

    If my guess is correct, coupled with your lack of aluminum welders, then I still recommend steel.
     
    Last edited: May 28, 2021

  4. JSL
    Joined: Nov 2012
    Posts: 811
    Likes: 64, Points: 28, Legacy Rep: 41
    Location: Delta BC

    JSL Senior Member

    Thanks ExileMoon - I pretty well agree 100% with your comments.
    Two features about using aluminum
    (a) the shop(s) can be a cleaner environment - less dust, etc.
    (b) less chance of sparking/ignition if flammable material is about (paint, cleaners, solvents, etc).
     
    Last edited: May 28, 2021
Loading...
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.