1950's 16ft Petrel

Discussion in 'Sailboats' started by Burkie, May 29, 2010.

  1. PAR
    Joined: Nov 2003
    Posts: 19,133
    Likes: 473, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    I've performed several fastener pull out and shear loading tests over the years and dowels (and trunels) are the lowest on the list, excepts for a bright nail. Dowels rely solely on its frictional fit and in shear, the dramatically weaker dowel, compaired to metal simply fails, as soon as the hole starts to elongate under load. If installed properly, wedged and tight, their pull out rivals a ring shank or a very coarse thread wood screw (like a deck screw), but doesn't hold a candle to a machine thread screw. In fact, WoodenBoat Magazine did a test some years back, which showed that the machine screw thread was superior to all, which was a surprise to those that haven't conducted these types of tests. Once you introduce adhesives, everything changes, except for the winner, which is still the machine screw thread.

    As to the head type. A countersunk head has the best compression strength, mostly because of the surface area being larger than a pan, oval or conventional nail head. Yes, if over driven it does tend to bury easier than a flat bottom style of head, but simply menas it's installed improperly and not a fault of the fastener head type.

    I like the Core Sound series and have a built a few. It's a fine "raid" boat, but it's too stable (for my liking) and not especially close winded, given it's rig. The Scamp is okay, just not my cup of tea. I think it's trying to be way more boat than it is - a 5 pound boob in a 1 pound bra kind of deal.
     
  2. locksafe
    Joined: Apr 2009
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    Location: polokwane, south africa

    locksafe Junior Member

    Scamp and fasteners -

    I think you pretty well summed it up as far as both the Core Sound Rig and Scamp goes - IMHO the Scamp is a big little boat - big on Materials, Big on Plan price, big on construction time , big on weight and at the end of the day still a 11 ft boat . For the total outlay i think there is a lot of good (better)boats out there to be built - in its defense i can say that the design brief was for a safe dinghy that could be built in a very small space (By Flat or apartment dwellers). but as far as ballasted dinghies go , the Roamer dinghy - is without a doubt still the benchmark. - it does not have a cabin to sleep in though but uses a tent for camping but is imho a very good dinghy if one wants to go for a safe cruising dinghy.
    I thank you for your insights on the fastener issue - for me , highly loaded areas on a boat still need a Galvanized bolt with big washers and a nut through it as well as a good Marine glue such as Resorcinol or Epoxy with their respective fillers.
     
  3. PAR
    Joined: Nov 2003
    Posts: 19,133
    Likes: 473, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Many years ago I addressed the "ocean capable, micro" market with what I considered was the smallest, practical real passagemaker. I found I couldn't get enough stowage in less than 18' on deck, to make long passages (what they all are in small craft) can be possible. There's a lot more to it than being able to build it in your bedroom. It has to be able to carry on, without killing the crew. It has to be able to carry enough food and water so you're still alive at the end and though outboards work, in deep water on a short boat, they're useless, so a option for a real inboard is necessary. These things just aren't possible on an 11' boat.

    http://www.boatdesign.net/gallery/showphoto.php/photo/24528/ppuser/36616

    This is my smallest practical and it has several rig, cabin and draft options available.

    There's an old saying among most of the professionals, which is - if it has to be strong, use a through bolt. We've come to trust goo's, but the idea of a big hunk of metal restraining our best efforts to break stuff . . .
     
  4. locksafe
    Joined: Apr 2009
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    Location: polokwane, south africa

    locksafe Junior Member

    micro cruiser

    That looks like a very wholesome little cruiser Paul. and what you say about inboards makes sense. I know there is an Ultra long shaft outboard made by Tohatsu in 8 hp with charging module (to charge a boat batteries) wich might work in an engine well . I had a look at your 26 ft cruiser on your website as well and thought that that might make a very nice cruising boat as well . I addition to that , Vincent Reddish designed a Junk Rig for a 26 ft Vertue that uses something like 320 sq ft of sail that will be perfect for this boat on an unstayed rig which would be my preference for a cruising boat . It is a very easily build Junk rig and is used by a lady that cruises by herself on a Vertue 26.(google "Cruising on Speedwell of Hong Kong") she had a flat cut Sail made by Pete Hill and then some years later changed it for a Cambered Panel junk which she didnt like and later changed it back for a new flat cut junk sail of the same size - the same as the one Vincent Reddish used on his Vertue. - she made the last two Sails herself. I had a chat with Pete Hill and he was kind enough to send me the mast sizes for the wooden Mast that he built for her boat - I think that mast has been on her boat for the last 15 years or so without problems and is in a Tabernacle for lowering to service said mast.
    What is the 17 ft boat that you have on your plans list like ? Is it a fast boat similar to a Core Sound 17 or different ? I noticed that it has a V bottom wich i like and it looks like a capable boat . I can mention that i dont like the Bermuda rig and would rather go for something that you show on your plans or idealy a standing lug with jib or Balanced lug without jib.
    regards , Hannes
     

  5. PAR
    Joined: Nov 2003
    Posts: 19,133
    Likes: 473, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    The 17'er I'll assume is Murphy and it's was designed for heavy air work, so is a bit under area'd and and has more freeboard than typical of a day boat of this scale. She can plane off, though you'll need a fair bit of wind, but her buttocks are steep enough to force you to work hard at sustaining the plane, which is the point for a heavy air day boat. The CS-17 would accelerate quicker and get on plane in lighter wind strengths, but Murphy would out point the CS-17 and maneuverability would be about the same. Murphy would be more comfortable in stiffer winds, though boat are still day boats and the average sailor will be running for shore when SCA's go up. You could put a bigger rig on Murphy and she'd do well. She currently has 3 rigs available for her, the Bermudian sloop, which can be used as a cat, leaving the jib below deck and moving the mast to a forward step. Thee's also two gaff cat rigs. All the rigs are free standing and rotating, though the sloop benefits from shrouds at the jib head tang, for best windward effort. I'm not much on any of the lugs or the junk rig.
     
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