Split mast

Discussion in 'Boat Design' started by AdrienJousset, Jul 13, 2010.

  1. AdrienJousset
    Joined: Nov 2008
    Posts: 23
    Likes: 1, Points: 0, Legacy Rep: 31
    Location: Southampton

    AdrienJousset Junior Member

    Still for my 26 footer sport boat. I would like to have any ideas, thoughts or solutions to be able to fit a 12.32m mast into a 30ft container of internal length of 8.93m. What about a mast that splits into two parts, the top one fitting over the bottom one. This fitting probably located at the spreaders level.

    How bad it would affect the stiffness of the mast? Would it be that heavier? Any major risk of mast failure?

    ???
     
  2. alan white
    Joined: Mar 2007
    Posts: 3,731
    Likes: 122, Points: 0, Legacy Rep: 1404
    Location: maine

    alan white Senior Member

    What material?
     
  3. AdrienJousset
    Joined: Nov 2008
    Posts: 23
    Likes: 1, Points: 0, Legacy Rep: 31
    Location: Southampton

    AdrienJousset Junior Member

    Aluminum... idealy.... or carbon
     
  4. Paul B

    Paul B Previous Member

    Why a 30 foot container?

    Many masts have a spice in them, almost all with a total length of over 40 feet. In most you don't see it because it is a welded splice and ground down and painted over.

    It is very possible for you to add a screw splice into either an alum of carbon rig. I would position it as low as possible, in the through-deck or gooseneck area would be good. That way the extra stiffness is doing some good, whereas extra stiffness at the spreader area would add weight where you don't want it and would put a hard spot in your mast bend.
     
  5. AdrienJousset
    Joined: Nov 2008
    Posts: 23
    Likes: 1, Points: 0, Legacy Rep: 31
    Location: Southampton

    AdrienJousset Junior Member

    Because the hull fits in a 30ft container...

    Thanks for the reply... I am going to contact mast builder to see what solution they can have. I wanted to make sure my idea was not crazy!!!:)
     
  6. tom28571
    Joined: Dec 2001
    Posts: 2,474
    Likes: 116, Points: 63, Legacy Rep: 1728
    Location: Oriental, NC

    tom28571 Senior Member

    Lots of unstayed two piece masts around and they do fine. A stayed mast should be even more stable. The top section fits inside the lower in the same manner as the Laser mast with collars made of fiberglass. The joint is just above the spreaders to avoid interference problems with spreader fittings. The sail track or luff groove fitting will bridge the step in the joint with no problem if its fitted carefully.

    Paul types faster. You can use his suggestion and many masts are built that way. This is preferred if the mast section is an extruded one with luff groove included. My suggested method is for simple round section (home made) masts. Hard spots are a non issue.
     
    Last edited: Jul 13, 2010

  7. jg451
    Joined: Jul 2010
    Posts: 17
    Likes: 1, Points: 0, Legacy Rep: 34
    Location: portland,oregon,usa

    jg451 Junior Member

    Hi Adrien,
    Obviously you wish to be able to demount and disassemble the mast for storage. I assume the trailing edge of the mast has either a track or groove for the sail. I remember in my misbegotten youth wooden masts with hinges! In all seriousness broken masts bigger and more expensive and harder used than yours are spliced for repair with no great problem. Ergo a pinned splice for your application should be fine, gravity will work in your favor. Many masts fail at stress points, the spreaders are certainly a stress point. With a hollow aluminum extrusion there exists a ready made section (with modification best done by professionals) for a splice. My only concern is wracking and wear at the pin locks and perhaps moisture in the mast.

    Regards, Jon
     
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.