Finishing a new boat kit

Discussion in 'Boat Design' started by reelpleasure, Feb 24, 2013.

  1. reelpleasure
    Joined: Feb 2013
    Posts: 27
    Likes: 1, Points: 0, Legacy Rep: 12
    Location: Massachusetts USA

    reelpleasure Junior Member

    Hello,

    I am new to this forum. I am contemplating having built and then finishing a boat kit this coming year.

    30 footer, solid glass hull, cored top and wash rails. Engine/transmission shaft rudder install.

    Finishing the boat will include fuel tanks, steering, wiring lights, exhaust all the mechanical stuff. I have many years of experience in installing the mechanical stuff but what I have NOT done is finish work.

    I have two ways to complete the boat. BTW, the boat will be a lobster/cruiser day boat, nothing fancy.

    I'll have to build an enclosed head up front with a door. Frame in a very small fridge. Build the helm dash, decks, etc. There will be glassing, shaping fairing, rolled gel coat, nothing fancy.

    I can build out the boat two ways.
    1. Using marine plywood, resins, tape, sand, lightly fair and roll on gel coat...
    or
    2. Use composite panels such as Coosa board, Divinycell, Nidacore and the like.

    I'd guess 80% or more of the Maine lobster boats are finished out of wood with mat/resin/gel coat skins.

    Boating is a passion/hobby of mine. I have the time and help to do the project.

    I've never worked with deck putty, fiberglass mat, tape, fairing compounds or gel coat applications.

    I want to do a "small project" or "piece" to get a sense of what's involved to do it right and get a "decent commercial grade pleasing to the eye durable finish that my kids are not ripping out and redoing 10 years from now.

    I've read as much as I could find on weight savings of composites vs plywood,
    maybe 1/3 when completed.

    Attached are a few pictures of what I'm asking about.
    The pics are various.
    Wood composite mix.
    100% composite panels taped with roll on gelcoat or sprayed.

    Ideally what I want are 4X8 light weight non-wood panels to cut and putty together. Tab in the corners with fiberlass and resin. Round the edges, fair smooth as need be.
    On the finished side roll on gel coat fairly smooth that will wipe up and clean easily and of course be durable.

    Where do I begin? Or not ???

    Thank you,

    ReelPleasure
     

    Attached Files:

  2. PAR
    Joined: Nov 2003
    Posts: 19,133
    Likes: 494, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    The major reason you're going to see sheathed plywood a lot, is cost versus strength/stiffness. Yep, there's lots of choices, but none rival sheathed plywood in strength and stiffness when you care about cost. If you have more money than you know what to do with, you can look into pre-finished NidaCore.

    [​IMG]

    It's already got 'glass on both sides and it's ready to cut and tape into a shape or structure. A 5/8" thick, 4'x8' sheet (just like plywood) is about $350 bucks (ouch). A 1/2" sheet of quality marine plywood is about $85 bucks (BS-1088 meranti - Hydrotech). Toss a 4-6 ounce 'glass sheath on it and you'll add, maybe another $30 bucks in materials. Yes, the plywood will be heavier, but it'll be strong, stiff and it's easy to screw an antenna bracket (or whatever) to it, if necessary, which isn't the case with a honeycomb core (or foam).

    Look around, you'll find all sorts of stuff, some good, some really expensive, other less desirable, but still all will cost a lot more.
     
  3. sean9c
    Joined: Jan 2011
    Posts: 289
    Likes: 4, Points: 18, Legacy Rep: 35
    Location: Anacortes,WA

    sean9c Senior Member

    I agree with PAR, you're not likely going to beat the economy and utility of ply. It'll end up a little heavier but unless weight is a big concern this might not be an issue. Another thing to remember if using Nida Core is that if you are going to have exposed panel edges you need to cut back the honeycomb core and then back fill the edges with putty. Down side of using ply is that it seems to be just about impossible to find ply that's flat and stays that way.
    One thing I might think about doing is use Coosa board for all the under cockpit floor framing. It's nice that it's waterproof and if you have to drill holes to run wires etc you don't have to worry about sealing the edges
     
  4. reelpleasure
    Joined: Feb 2013
    Posts: 27
    Likes: 1, Points: 0, Legacy Rep: 12
    Location: Massachusetts USA

    reelpleasure Junior Member

    Thanks for getting back to me.
    I keep coming back to the same conclusion as you.

    I have not added up the total sq feet of material I'll need.

    As I stated, the boat will be a day boat. Pull some lobster traps, fish with the grand kids and some cruising.

    What would be the "step process" using say 3/8" marine plywood to say build a helm dash and finish it with rolled gel coat as in these pictures?

    I will have to "contour" the the helm dash a bit. I do I bend or sculpt plywood panels "just a bit" ??
     
  5. michael pierzga
    Joined: Dec 2008
    Posts: 4,862
    Likes: 115, Points: 0, Legacy Rep: 1180
    Location: spain

    michael pierzga Senior Member

    I dont understand what Im looking at ?

    The watertight engine room in the fourth picture is very worthwhile. Added sound insulation is required .... blower ventilation is needed...the space allocated for the engine looks good. the raised Hatch cover detailing will be important .

    The engine room ventilation in the sixth picture will make for a very noisy wheelhouse.

    The Chase tubes on the outboard rig are poorly designed. If water enters the tubes the electric or control cables inside will spend thier life in stagnant water. Run tubes under side decks and be certain that a drain is placed somewhere in the tube to shed water into a bilge. .

    The household carpentry in the third picture should be avoided.

    A seaworthy boat has several waterproof compartments under the cockpit sole isolating the shaft tube stuffing box , rudder gear , fuel tanks

    Nothing wrong with marine ply, epoxy, glass.

    Since you are not carrying cargo weight is not so critical.

    Foam core products are nice...and expensive.

    Diesel tanks should be removable for service...this means access hatchs in the deck .

    Interior fit out is your choice. Foam core ply is often used. Coosa could be a choice.
    All cored work requires good engineering.

    Nidacore is also worth investigating for sole material.

    I dont see many uses for gelcoat.

    Suggest you refine your design and post drawings.
    Also worthwhile to visit the shipyard, get on your hands and knees with a camera and investigate detailing on similar boats.
     
  6. reelpleasure
    Joined: Feb 2013
    Posts: 27
    Likes: 1, Points: 0, Legacy Rep: 12
    Location: Massachusetts USA

    reelpleasure Junior Member

    Thank you for the critique of the pics.
    They are representations of the way some down east boats are built.

    OK, let me try to keep the questions I'm asking more simple.

    I want to do a project to prove or disprove my ability for "fiberglass and finish work".:p

    Cutting panels, fastening together with deck putty. Shaping the edges, taping the edges and corners, covering with cloth and vinylesther resin, covering the panels with cloth with resin, fairing sanding and rolling on gel coat.

    For comparison I'll give a go two ways.

    I"ll pickup 2 panels 1/2" marine plywood, and the other a lightweight 1/2" Nidacore, Coosa, Penske or Divinycell panel.

    I'll build a box for a seat, the outside with a smooth shiny gel coat finish.

    The box has to be strong enough for a seat, 400 lb capacity.

    What do I need for tools and products?

    What is the process ?

    Thanks, Reelpleasure
     
  7. PAR
    Joined: Nov 2003
    Posts: 19,133
    Likes: 494, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    The major reason you're going to see sheathed plywood a lot, is cost versus strength/stiffness. Yep, there's lots of choices, but none rival sheathed plywood in strength and stiffness when you care about cost. If you have more money than you know what to do with, you can look into pre-finished NidaCore.

    [​IMG]

    It's already got 'glass on both sides and it's ready to cut and tape into a shape or structure. A 5/8" thick, 4'x8' sheet (just like plywood) is about $350 bucks (ouch). A 1/2" sheet of quality marine plywood is about $85 bucks (BS-1088 meranti - Hydrotech). Toss a 4-6 ounce 'glass sheath on it and you'll add, maybe another $30 bucks in materials. Yes, the plywood will be heavier, but it'll be strong, stiff and it's easy to screw an antenna bracket (or whatever) to it, if necessary, which isn't the case with a honeycomb core (or foam).

    Look around, you'll find all sorts of stuff, some good, some really expensive, other less desirable, but still all will cost a lot more.
     
  8. michael pierzga
    Joined: Dec 2008
    Posts: 4,862
    Likes: 115, Points: 0, Legacy Rep: 1180
    Location: spain

    michael pierzga Senior Member

    Epoxy is superior. Epoxy , eglass and marine plywood are the cheapest combination and are proven to produce a superior product.

    Before you begin you should work up a Bill of Materials and solicit a few bids.

    Construction grade marine ply is called Meranti 6555. A 12 mm sheet costs about 75 dollars and weights about 50 lbs. Construction grade timber..... Douglas fir, is about 5 dollars per board foot. Epoxy runs about 75 dollars per gallon.



    The most valuable tool for building boats is a work bench...a big one 16 x 4 , to handle sheet goods.

    Components are built off the boat..then installed.

    Since you are in the North climate control is important.

    A dust control system is highly recommended.
     

  9. viking north
    Joined: Dec 2010
    Posts: 1,868
    Likes: 92, Points: 48, Legacy Rep: 1146
    Location: Newfoundland & Nova Scotia

    viking north VINLAND

    Reelpleasure -- Seek out the local areas boat handy man carpenters. There's always a few older self taught guys that are dam good at their trade but semi retired and just want to work a bit of part time. Also check the boat building /repair shops, times are slow and they might be more than happy to supply an employee on a part time basis at a good rate just to keep them. Either situation will get the the project set up and going, get you started, drop by for a few hours work as required and direct you as to what to do until their next visit. I've been personally employeed on many ocassions as such.Wish I were closer I'd fit you in with work on my own build. I'm not that far north maybe you can fly me back and forth in your private jet for a couple of days a week. :) -- Good luck -- keep on the forum with any questions and lots of photos ---
    P.S. Also a good idea to hire a designer to do you up a general layout of the project and to detail those tricky build areas. I'm primarly a builder and this approach worked really well for me. Be the best money you ever spent as it gives direction and keeps the project moving in efficient steps. I.E. less of those " Oh I should have installed the galley here that would have allowed me full bunk length there" We've all been thru it --
     
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