Lightning Sailboat 19' build

Discussion in 'Boat Design' started by FirstLight, Aug 21, 2012.

  1. FirstLight
    Joined: Sep 2007
    Posts: 75
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    Location: North Carolina

    FirstLight Junior Member

    Have always loves this classic design from the board of Sparkman and Stevens. There's a small fleet here in our area. For a winter project I want to build one. There are several sets of offsets with the fast design that I've brought into Rhino.

    I'm trying to determine what the strongest\lightest build technique would be (no foam) for a one off lightning. Cold molding would seem the answer however the hard chine doesn't seem to fit the process as well. Then there is the frame method the Gougeon boys outline in their big blue bible.

    Any thoughts or ideas??

  2. gonzo
    Joined: Aug 2002
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    Location: Milwaukee, WI

    gonzo Senior Member

    Balsa planks core composite should be the lightest and stiffest. That design was made for carvel construction and has very easy lines.
  3. DCockey
    Joined: Oct 2009
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    Location: Midcoast Maine

    DCockey Senior Member

    Do you plan to have the boat measured and certified as a class boat? Looks like you need to start with a set of official plans even if you are using someone's offsets which fit withing the class tolerances:

    The boat would also need to meet the rules:
    Some excerpts from the rules:

    1.The purpose of the Plans and Specifications for the Lightning is to insure to as great a degree possible that all hulls and sails are equal on the racecourse. It is impossible to write every single variation that may become apparent in the future, and also impossible to set out detailed Specifications that would preclude a challenge at sometime in the future to obtain a racing advantage. Therefore, any boat or sail having features which are not consistent with this purpose will be disapproved and will not race even though there may not be a Specification directly dealing with the item in question. If in doubt, request a ruling from the Measurement Committee before proceeding.
    Sounds like anything considered to different than normal might be disallowed. Best to check before building the boat.

    Carbon fiber construction or carbon fiber components are strictly prohibited except for cam cleats, blocks, pulleys, rudder reinforcement, and hiking sticks. August 1998) (November 1999)(March 2001)

    14.The Lightning shall be constructed of woods generally used in yacht construction, such as marine grade plywood, cedar, mahogany, spruce or fir, or glass reinforced plastic, or a combination of these materials.

    Only professional builders whose building techniques have been certified by the Measurement Committee will be permitted to build glass reinforced plastic Lightnings.

    An amateur built Lightening would have to be wood construction

    Glass-reinforced plastic bottom construction shall have a skin thickness of 1/16" (1.587 mm) minimum; core thickness of 3/8" (9.525 mm); core density of 4 lb./cu.ft. (64.103 kg/cubic meter) minimum; inner skin thickness 1/16" (1.587 mm); and five frames minimum in the station 3-1/2 to station 7-1/2 area.
    Glass-reinforced plastic side construction shall have a skin thickness of 1/16" (1.587 mm) minimum; core thickness of 1/4" (6.350 mm); core density of 4 lb./cu.ft. (64.103 kg/cubic meter) minimum; inner skin thickness 1/16" (1.587 mm) minimum.

    Wood construction techniques shall be equivalent in strength to the frames, planking, timbers, etc. as shown in the original plans to insure a rigid hull structure, and shall be of a uniform thickness, in order to hold its shape and specifications while racing.

    Frames - There shall be a minimum of twelve frames per side, located at stations 1 through 9 and stations 3-1/2, 5-1/2, and 8-1/2.

    Frames shall be a minimum of 6.35 mm (1/4") thick and a maximum of 101.60 mm (4") deep, and be typical of accepted construction technique.

    Frames at stations 3, 3 1/2 and 4 shall consist of or shall be reinforced at minimum dimensions of 22.225 mm (7/8") thick and 50.80 mm (2") deep along the entire hull bottom and sides.
    Keel, Chine and Sheer stringers - minimum thickness 19.05 mm x 38.1 mm (3/4" x 1 1/2").

    Hull skin stringers - minimum thickness 12.70 mm x 19.05 mm (1/2" x 3/4") - minimum quantity three per side.

    Bottom stringers - minimum thickness 12.70 mm x 19.05 mm (1/2" x 3/4") - minimum quantity running parallel to the keel will be five per side.

    Deck stringers - minimum thickness 12.70 mm x 19.05 mm (1/2" x 3/4") - minimum quantity running parallel to the centerline will be five per side.

    16.Sides and Bottom shall not be thinner than:
    Solid wood - 15.875 mm (5/8")
    Plywood - 7.9375 mm (5/16")

    17.Deck shall be well braced so that it will not flex under the weight of the crew, and shall not be thinner than:
    Solid wood - 11.1125 mm (7/16")
    Plywood - 6.35 mm (1/4")

    Glass reinforced plastic construction of the fore and aft deck shall have a skin thickness of 1/16" (1.587 mm) minimum; core thickness of 1/2" (12.70 mm) minimum; core density of 4 lb./cu.ft (64.103 kg/cubic meter) minimum; and inner skin thickness of 1/16" (1.587 mm) minimum.

    18.Wood transoms shall have a minimum thickness of 12.70 mm (1/2"). Fiberglass transoms shall have a minimum thickness of 3.175 mm (1/8").

    There may be a maximum of two transom ports, and they shall not exceed 32 sq. inches area per port.

    19.The centerboard trunk shall be constructed of glass reinforced plastic not less than 4.7625 mm (3/16") thick, or 12.70 mm (1/2") solid wood. The centerboard trunk shall be braced so that it will not flex. The hull number as assigned by the ILCA shall be permanently fixed by indentation, plaque or separate numbers (decals) molded under clear resin at least 50.80 mm (2") high in the starboard side of the trunk.

    20.Should there be a question as to thickness or uniformity of a boat, the Measurement Committee may require that a plug or plugs be taken to determine same at no cost to the Association. The Measurement Committee may test for moment-of-inertia or center-of-gravity for equality of weight distribution for any boat and set standards should M-O-I testing be required in the opinion of the Committee.

    21. It is permissible for the wood boat builder to add a layer of glass reinforced plastic cloth saturated with polyester or epoxy resins. However, the boat will comply under these Specifications as a wood boat.

    22.Weight of the hull and rigging shall not be less than 317.5179 kg (700 lbs.). The boat shall be weighed with spars, standing rigging, halyards, main, jib and one set of spinnaker sheets, boom vang gear, rudder, tiller, hiking stick, centerboard, one spinnaker pole, hiking straps, attached compasses, built-in non-removable drawers or compartments of reasonable size and construction, and automatic bailers. Weight does not include sails, paddle, boom crutch, removable drawers, loose equipment, containers, life preservers, tools, anchors, anchor lines and other miscellaneous lines.

    Looks like your options are limited if you want to be measured and accepted as a class boat.
  4. Petros
    Joined: Oct 2007
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    Location: Arlington, WA-USA

    Petros Senior Member

    I would recommend sticking with the rules, if you do not, not only will you not be allowed to sail in the races, it will not have much resale value when you are done with it.

    It appears there is no advantage to a lightweight build since rules require a 700 lb hull anyway.

    You might consider finding a used one and refurbish it, it will cost less and get you on the water faster.
  5. tunnels

    tunnels Previous Member

    Are you into compatition or just playing about ??
    Like has been said buy a second hand boat and refurbish it like new do a 100% strip of all and everything and scrape the paint off and respray etc etc But if the boat has a balsa cored hull you can bet 100% that it will be wet and heavy so theres you chance to do a rebuild rather than start from scratch !!
    To SAVE IN WEIGHT if you do a rebuild use balsa and what ever glass and then infuse it !!! will never be able to make it any lighter than that , use paints and not gelcoats
    Pick you glass carefully !!woven glass materials are thicker and so used more resin , differant cloths for differant uses ,also the type of glass ask and choose wisely , use epoxy resin and make sure you speak to the chemist if possible and get the strongest with a little flex . (Not all resins are born equal ).
    save weight every where possible . there could be raised eyebrows of you under weight but han always screw a lead block ti the middle to bring it to the minimum weight and as the boat gets older get it re weighed and change the lead block !
    You not breaking the rules just bending them a little !!
    But, what do i know !:(
  6. sonosail
    Joined: Mar 2008
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    Location: CT USA

    sonosail SONOSAIL

    Lightning class plans

    About 20 years ago the Lightning class created a new set of plans/rules for plywood contruction. I think one boat boat was built using the WEST system.

  7. philSweet
    Joined: May 2008
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    Location: Beaufort, SC and H'ville, NC

    philSweet Senior Member

    They are wonderful boats but you should be aware that some of the top small boat builders in the country have built these things. Expectations for a wooden hulled Lightning will be very high among class members, and not just among the elite racers. The woodies used to have a very slight rules advantage over the glass boats and most of the national champs went with woodies. There is a ballast allowance of twenty pounds on the centerline. Any extra has to be distributed elsewhere. If I recall, the object of the game is to come in exactly twenty pounds light at 680 in measurement trim and then max out the centerline ballast allowance. So basically, you assemble your rig, lines, hardware kit,CB, and rudder and weigh that. Then build the whole thing with temp fasteners and carefully weigh it again. Then take it all apart and put it together permanently after any adjustments allowing for glue and paint and fairing putty. Am I dreaming or were the old hulls all double diagonal planked on the bottom. I used to sail on one until I was five. I soloed it on the Chesapeake. My parents were more than a little annoyed I took the boat out. But all I remember was the fun I had and Mr Keck coming out and asking me to please return to the dock. Then he motored back to the dock and let me sail her in. Mr Keck gets lots of points for letting me do that and not towing me in. I've sailed on them once or twice since then.

    Keep all of your reciepts and document the build as you go and ask lots of questions of the association members.
  8. tunnels

    tunnels Previous Member

    Have you ever seen the differance in weight of sheets of ply wood out of one pellet . go through a stack sometime with a set of digital scales !! you will be amazed i promiss !!:confused:

  9. FirstLight
    Joined: Sep 2007
    Posts: 75
    Likes: 1, Points: 8, Legacy Rep: 21
    Location: North Carolina

    FirstLight Junior Member

    Old Boat..

    Guys.. Great information!!! After looking through the options and debating building from scratch I opted against it. You guys made some good points. Thank you so much. A few weeks back I picked up a 1970's Lightning for $100. I figured I would see if it was worth rebuilding to have some fun with it.

    I posted a new link since I am down to the outer skin in one section. I am probably crazy for giving this a shot but if all goes bad I'll have about $300 invested and that's all. And if the hull goes away I have a brand new mast, new boom, new spinnaker, good set of practice sails and about $500 in Harken hardware, a trailer in great shape and a SST centerboard.

    I figured I'd try removing the foam core in one area and stiffening to see what I get. Here is the link. Once again. Any and all information greatly appreciated!!!

    Here is the link:
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