Rules for seaplanes

Discussion in 'Fiberglass and Composite Boat Building' started by vmeertens, Feb 15, 2012.

  1. vmeertens
    Joined: Mar 2009
    Posts: 11
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Belgium

    vmeertens Junior Member

    Dear all,

    Let me first introduce myself, since this is my first post:

    My name is Vincent M. and I currently work at a Dutch shipyard as researcher.

    A couple of years ago I obtained my diploma as an Industrial Engineer Electro mechanics at the KaHo St-Lieven. After these studies I opted for an additional degree in: Civil Engineering - Maritime Techniques, at the University of Ghent.

    Now I’m almost 26 years old and I started as a part time freelance Naval Architect. The first objective is to learn a lot and to be involved in a large amount of projects.

    One of these projects is the following:

    I have been asked to size the sandwich hull construction, stiffeners etc. Since I don’t have a lot of experience with composite hulls, I was wondering which rules are the best fitted for this type of calculations?

    Currently I’m comparing the ABS rules “High Speed Craft” vs loyd’s rules for composite hulls. My first opinion is that ABS is quite easy to use, but I’m more confident with Loyd’s.

    So I’m really interested in the opinion of experienced boat builders. Any kind of help and/or remarks is appreciated!


  2. fcfc
    Joined: Feb 2005
    Posts: 779
    Likes: 29, Points: 28, Legacy Rep: 399
    Location: france,europe

    fcfc Senior Member

  3. daiquiri
    Joined: May 2004
    Posts: 5,373
    Likes: 252, Points: 93, Legacy Rep: 3380
    Location: Italy (Garda Lake) and Croatia (Istria)

    daiquiri Engineering and Design

    It is an airplane, not a boat, so fcfc's advice is correct. The bottom loads have to be determined according to JAR 23 standard.
    You can download the JAR 23 from this page: . Check the page 72 of the document, you'll find the procedure for calculation of water loads on the plane's floats.

    Ooops, the pdfs on the JAA page don't contain the text of the standard. You can find it here, page 72 is of interest for you:
  4. Petros
    Joined: Oct 2007
    Posts: 2,936
    Likes: 148, Points: 63, Legacy Rep: 1593
    Location: Arlington, WA-USA

    Petros Senior Member

    I have worked in both aerospace and marine industries as an engineer, although the Lloyds standards are excellent for ship and yacht designs, they are not suitable for aircraft. Aircraft design and production is totally different process, if you used boat rules it would be way too heavy and would not create a viable aircraft. Likely it would not even be able to get off the water.

    Therefore you have to go with aircraft standards. Usually if you meet the US FAA standards, it will be recognized by other countries. You likely have a larger market in the US as well (especially if you intend to sell it as a kit). As a home-built "experimental" category aircraft, there are minimal requirements however using the FAA standards will make it suitable for full certification at a later date.

    The design and construction standards for aircraft are much more detailed, requiring a lot of detailed analysis, much tighter tolerances, higher quality materials. Also the maintenance standards are much higher as well. All this allows you to deign a much lighter structure than you would for a boat. Even small aircraft are usually designed by teams of specialists, unlike most boats. A lot of testing is required after the first one is built, even on an Experimental category aircraft. One of many reasons everything having to do with aircraft is so costly.

    I would go homebuilt or Light Sport Aircraft if the marketing plans fits that objective, otherwise very deep pockets will be required before you even get to the first launch/flight.

  5. vmeertens
    Joined: Mar 2009
    Posts: 11
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Belgium

    vmeertens Junior Member

    @ Fcfc, daiquiri and Petros:

    Thanks a lot for all your replies! I will follow the FAA for the construction of the hull.

    Maybe I have to clarify myself: I was speaking about the "wet hull" and thus not the whole fuselage. That's the reason why I opted for marine rules instead of aviation rules.

    But I assume this doesn't change a lot on the result of the discussion :)


    Vincent M.
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.