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Thread: John Henry... Easy scarfing and glueup

  1. #1
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    Default John Henry... Easy scarfing and glueup

    A good friend is starting a new build with my help.... and I thought photos of the John Henry scarfer attachment for a power planer might be of interest to those who have not had the chance to see one. I originally bought this sweet jig/tool for my first boat several years ago. The particular unit I have fits the smallest Makita power planer and scarfs plywood up to 3/8" thick. John Henry also has a larger scarfer jig that fits the next size up Makita power planer (4 3/8" width) and will scarf ply up to 1/2" thick. THIS THREAD WILL DOCUMENT THE ENTIRE BUILD OF A MAVERICK STYLE FLATS SKIFF OVER 6 PAGES ...

    Heres the John Henry scarfer attachment installed on the smaller Makita power planer. All you have to do is remove the metal base of the planer and replace it with the scarfer attachment. Its drilled and ready to screw on.



    Heres the basic setup for using the JHS attachment, two sheets of the stock to be scarfed, clamped down. The scarfer attachment only cuts the top sheet resulting in a 3" scarf cut to a fine feather edge at the top of the bottom ply panel. The bottom panel is just a guide for the jig.



    Heres the bottom of the scarfer attachment, showing the basic jig and how it works.





    The power planer and attachment set up ready for the first pass...



    Ply edge after one pass of the planer....



    Continued...
    Last edited by RodB; 04-07-2013 at 11:04 PM.

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    Default Re: John Henry... Easy scarfing and glueup

    Here showing the final pass, note: depending on how you set up the spacers on the up side of the edges, you can get the scarfer to leave a small shoulder at the top of the scarf cut, and with the feathered edge left as thick as the shoulder dropoff, you can end up with scarfs that line up and click together easily because of the shoulder. On average, it takes at least four passes with the planer to cut the scarf, and the final pass cuts very little material and the planer moves ever so easily...



    Here you can see the shoulder at the top of the scarf, which I prefer for ease of fitting the joints together.



    Many stitch and glue designs simply recommend using 4x8 ply panels cut the long way to fabricate bottom and side panels from 8 foot sections. Some designers recommend cross cutting 4x8 sheets of ply and scarfing enough 48" long panels together to achieve the required length of your boats bottom or side panel. This construction technique results in a much a stiffer panel and is much superior in most applications, even though it does require a bit more work. The following shows the breakdown of 3 4x8' panels so that a bottom panel can be glued together with 5 separate smaller panels of ply... You can see you end up with the required total length at the required width in a much stiffer overall panel.


    Edited to add clearer explanation 3/2/2010: by Rod B
    I have not really explained this properly above. The multi-scarfed panels that have been rotated are really an engineering method of optimizing the natural bend of the panels to fit the panel shape in the construction of the hull. The Designer of my first flats skiff and this current design, Tracy Obrien, told me long ago about this technique of fabricating panels. I think he pretty much recommends it most of the time in stitch and glue construction but it depends on the hull in question. The hull sections of the longer panels are "stiffened" from side to side across the hull with the 90 degree rotation. If you build a hull such as this with just longer sections of ply (ply sections cut along the 8 foot axis of the panel), the panels actually "cup" because of their increased flexability across the panel compared to the greater stiffness on the longer orientation.

    As you know, plywood sheets are stiffer in their longer orientation. Rotating the crosscut panels 90 degrees allows the panels to bend easier fore and aft...thus making for easier fitting of the panels to the shape of the hull. The resulting glued up panels are stiffer across their short side (sheer to sheer), but flex easier fore and aft to fit in their intended shape. According to Tracy, this is just taking advantage of the natural bend and flexability of the materials in an engineering sense to attain the shape of the hull easier
    .




    Here you see the basic setup of scarfed panels ready for glueup. Note the first, third, and fifth panels are laid down on the 2x6's (with polyethylene sheets between) with bevel up....so that only the 2nd and 4th panels are the only ones that have to be handled during clamping (bevels down). Just laying down panel #2 and #4 in place makes the operation much easier to accomplish with wet epoxy in play. Note: working inside sure beats the cold weather...



    As usual, all surfaces are coated with unthickened epoxy prior to applying thickened epoxy on one side of each joint before clamping.



    Here, after applying the thickened epoxy to the bevels of panel #1, #3, and #5, the 2nd and 4th panels are laid on top and stapled in place with only two staples (to be removed later), then the top plastic is laid in place and the top clamping piece of 1/2" ply is screwed down to the underlying 2x6 and plastic... for strong even clamping pressure.



    This particular stock is Merranti and will be the bottom of this 17 foot hull. The glueup will be left clamped at least over night.

    Continued... RB
    Last edited by RodB; 03-02-2010 at 09:02 PM.

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    Default Re: John Henry... Easy scarfing and glueup

    Another pic from another angle...



    A closeup of one of the clamped joints. I think this simple sheet rock screw clamp up system is hard to beat. I also like using polyethylene sheeting rather than wax paper because it offers more protection and always pulls away from any epoxy better than wax paper.



    Here, the clamping materials have been removed leaving very little epoxy cleanup/sanding/scraping/planing to be done. The majority of the excess epoxy can be removed with a sharp paint scraper... but for the thicker stuff... a sharp low angle block plane is hard to beat.



    A closer shot of a glued up joint. Note the small areas of squeezed out epoxy. These will be removed with a scraper and a block plane followed with a 6"ROS with 80 grit. If necessary a good belt sander is used to clean up the joints. Next step, drawing up the panel shape from the plans ... followed by cutting out the panel shape and then glassing both sides of the panel.



    RodB
    Last edited by RodB; 02-27-2010 at 11:39 PM.

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    Default Re: John Henry... Easy scarfing and glueup

    Thanks Rod , a very useful jig !
    '' You ain't gonna learn what you don't want to know. ''
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    Default Re: John Henry... Easy scarfing and glueup

    Thanks for the post.

    Is there any competative tool?

    Seems like this is a great tool.

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    Default Re: John Henry... Easy scarfing and glueup

    West Scarffer.
    I have used one for thirty years, just leave it attached to an old 7 1/4" skill saw.

    http://www.duckworksmagazine.com/05/...ffer/index.cfm

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    Default Re: John Henry... Easy scarfing and glueup

    I have been fiddling on something similar. It looks surprisingly similar, I have to say, but still a tad different....
    When you're chewing on life's gristle
    Don't grumble, give a whistle...

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    Default Re: John Henry... Easy scarfing and glueup

    Quote Originally Posted by RodB View Post

    Here, the clamping materials have been removed leaving very little epoxy cleanup/sanding/scraping/planing to be done. The majority of the excess epoxy can be removed with a sharp paint scraper... but for the thicker stuff. a sharp low angle block plane is hard to beat.



    A closer shot of a glued up joint. Note the small areas of squeezed out epoxy. These will be removed with a scraper and a block plane followed with a 6"ROS with 80 grit.


    RodB

    Great post, Rod. But I don't see a heat gun mentioned here. It would make this clean up step much easier.

    Steven

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    Default Re: John Henry... Easy scarfing and glueup

    Thanks for the photos Rod .I've never had that good a look at the John Henry ,although I've read about it for years .What slope of scarf ?

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    Default Re: John Henry... Easy scarfing and glueup

    Looks great. I have found that it helps to put a piece of "sacrificial" wood to each side of the board being scarfed. That helps with the entry and exit of the planer. However, with this attachment it may not be necessary.

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    Default Re: John Henry... Easy scarfing and glueup

    Heres an alternative, the circular saw jig you can make yourself... with a 7 degree jig angle... which works out for any thickness of stock. Courtesy of Tracy Obrien.



    A bit more elaborate... a ply scarfing table if you have a mind to build it. Both the jig above or this table allow more versatility with a larger circular saw blade...such as 8" etc. Note the angle of the face board is seven degrees.



    I understand the circular saw jig from the Gougeon Brothers is a good tool.

    Great post, Rod. But I don't see a heat gun mentioned here. It would make this clean up step much easier.
    I haven't used heat...but with a sharp paint scraper and a low angle block plane... followed with a sander... its only minutes to fix... I may try heat before applying the paint scraper, but it cuts the epoxy very nicely with a low angle pull of the handle... very simple and effective. I tend to use my Red Devil 2" paint scraper a lot on epoxy to avoid sanding. It works like a charm.

    Thanks for the photos Rod .I've never had that good a look at the John Henry ,although I've read about it for years .What slope of scarf ?
    The John Henry scarfer adjusts the angle of the scarf depending on the material thickness. As I said above, this jig fitted to the smallest Makita planer will do up to 3/8" ply with an 8:1 scarf. The larger Makita Planer jig will do up to 1/2" ply thickness with an 8:1 scarf. Naturally, if you scarf thinner materials then mentioned, you get a larger than 8:1 scarf. Its just a matter of the width of the planer blade and the angle you set the jig on with the spacers provided. The directions say to use the appropriate spacers for the different thicknesses of plywood.

    RodB
    Last edited by RodB; 02-27-2010 at 10:01 PM.

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    Default Re: John Henry... Easy scarfing and glueup

    Looks great. I have found that it helps to put a piece of "sacrificial" wood to each side of the board being scarfed. That helps with the entry and exit of the planer. However, with this attachment it may not be necessary.
    Yes, you are right, it is not necessary with the John Henry Scarfer attachment.

    By the way, the manufacturer of the John Henry SA used to supply this jig for other planers, I'm not sure if he still does. I know he has made them for the Makita 3 3/8", 4 3/8" and 6" power planers.

    It sure makes a nice scarf...



    RodB
    Last edited by RodB; 03-02-2010 at 08:51 PM.

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    Default Re: John Henry... Easy scarfing and glueup

    As usual, a great photo essay, Rod.

    Are you going to continue this on to show the rest of the build?
    Last edited by SMARTINSEN; 03-19-2010 at 12:01 AM. Reason: Misspelled Rod's name which I had thought I had previously corrected. Apologies
    Steve Martinsen

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    Default Re: John Henry... Easy scarfing and glueup

    Sure, why not?

    R

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    Default Re: John Henry... Easy scarfing and glueup

    Great stuff. Thanks Rob.

    BTW, I just showed this thread to my wife, because my living room is exactly the right size to build anything up to 16 ft. She just gave me "the look". You guys know "the look", right?

    - Norm

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    Default Re: John Henry... Easy scarfing and glueup

    We were lucky the atrium doors will lets us get it out of the house... and we gain at least a couple of months not waiting for warm weather...

    R

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    Default Re: John Henry... Easy scarfing and glueup

    Thanks for posting, I have always wondered how this jig worked. Was leery about buying one because it only did up to 3/8 ply. I guess the one for the larger Makita will have to wait because I have the same planer you have.
    Very interesting panel layout, nice work...

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    Default Re: John Henry... Easy scarfing and glueup

    I use a somewhat similar jib with a router...clean as a whistle....I used the skil saw method for quite a while, but I am not fond of skil saws and found the router easier to work with.
    Wakan Tanka Kici Un
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    Default Re: John Henry... Easy scarfing and glueup

    Great info/tutorial. Thank You.
    BTW Whats the boat?
    There are two kinds of boaters: those who have run aground, and those who lie about it.

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    Default Re: John Henry... Easy scarfing and glueup

    Lets just say the design is a compilation of features of some of the best flats boats made today... number one criteria... poles well in windy conditions... always points into the wind... and handles rough water with ease... will have trim tabs. A nice large deck with side decks for complete walk around. Light in weight, poles quietly when sight casting for fish (Tarpon, Reds, Specks, etc).

    We had the plans developed so that we own the plans... it should end up being around 500 lbs in dry weight, an approx 17 foot V hull.


    Thanks for posting, I have always wondered how this jig worked. Was leery about buying one because it only did up to 3/8 ply. I guess the one for the larger Makita will have to wait because I have the same planer you have.
    Very interesting panel layout, nice work...
    The 4 3/8" power planer from Makita ( the next larger one) is a better rig because it can scarf anything up to 1/2" ply. The negatives are this tool costs at least $200 and the carbide blades for it are quite expensive. I also have this planer and use it for general power planer use...but I was lucky and found it in a pawn shop for $60. I have long planned on getting the John Henry scarfer attachment for it, just haven't needed to scarf 1/2" stock yet. I also like having an extra power planer around for general work, like taking off 1/8" from the edge of a transom, etc.

    The John Henry Planer-Scarffer Attachment is easily installed on the Makita 1900B, Makita 1912B, and the Porter-Cable Model 9125 planers. The attachment is not limited to these particular models.

    Availability
    The John Henry Planer-Scarffer Attachment is available for the 3 1/4" and 4 3/8" planers or can be purchased as a unit with the planer and attachment. Carbide blades are highly recommended and are also available.
    Heres the Makita power planers available... I think they are really quality tools...

    http://www.makita.com/en-us/Modules/....aspx?CatID=32

    RodB
    Last edited by RodB; 03-01-2010 at 05:12 PM.

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    Default Re: John Henry... Easy scarfing and glueup

    Not to hijack but would this scarphing technique work well for deck joins?

    Where do ya get the jig? I searched the web and didn't find a source.
    Last edited by CharlieCobra; 02-27-2010 at 08:06 PM.

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    Default Re: John Henry... Easy scarfing and glueup

    This is a very easy way to scarf any panels less than 1/2" in thickness if you have the larger 4 3/8" wide Makita planer. The smallest Makita planer will only do up to 3/8" ply. The Makita 6" planer can do about anything....

    Here are the links to the John Henry Planer scarfer attachment.

    John Henry, Inc.
    P. O. Box 7473
    Spanish Fort, AL 36577
    (251) 626-2288
    information@johnhenryinc.com

    http://johnhenryinc.com/index.html

    http://johnhenryinc.com/2.html

    http://johnhenryinc.com/3.html

    RodB
    Last edited by RodB; 03-01-2010 at 05:13 PM.

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    Default Re: John Henry... Easy scarfing and glueup

    Setup for cutting out the side panels. Its important to have both panel blanks clamped together at each end... and then cut both panels simultaneously for exact mirror images. Keeping the panels on 2 X 6's on a level floor is a very good way to cut out the panels. Heres the panels ready for cutting... Naturally, the basic panels are fabricated slightly oversized... a chalk line is popped... and the measurements from the plans are all marked... and of course a nice 12 foot batten is used to connect the dots.



    This is one of the premier situations where a worm drive circular saw excels as the tool of choice. I like the Makita Hypoid saw because it is the lightest saw of this type with plenty of power and easy to handle. The magnesium model is even lighter yet. The Dewalt framing circular saw is also on the smaller side and handles well. I tend to use the Hypoid for most general circular saw cutting because of its smooth power and the easy to see "left" blade. I use my sidewinder circular mostly for panel work with the Eurekazone smart guide system.

    Of special note here is the ease of control of worm drive saws because of their "Gyro" effect stemming from the fact that the motor and the blade are spinning on two separate planes. This two plane geometry results is a very nice "Gyro" effect which makes the worm drive saw very very easy to control. You can follow a line with precision and plenty of control using one hand... where a standard "sidewinder" circular saw can "self steer" with a carbide blade and is more difficult to control.

    I was able to cut both the bottom and side panels for this design with one hand and I pretty much stayed within 1/16" or less... away from the lines drawn. Be sure to adjust the depth of cut of your saw blade to just past the thickness of the two ply panels clamped together... so you won't waste energy in cutting too deep in the sacrificial 2 X 6's underneath. DON'T FORGET YOUR KNEE PADS... THEY ARE GREAT FOR US OLDER GUYS!



    The Hypoid saw also does a great job in cutting gentle curves like shown here on the side panels.



    Heres the side panels pretty much cut out except for the bow end which is a quick straight cut at the other end. Note all clamps are strictly for holding both panels together so that you end up with two identical panels. Only use "C" clamps on the ends and across from the side you are cutting... as they have a much stronger hold on the panels and are much better than the spring clamps.



    Naturally, after a reasonably close cut to the "lines"... the low angle block plane is used to "plane to the line" precisely... for very accurate panels. If you leave too much gap between the line and your cut... you will learn quickly that you only make more work for yourself... using the low angle block plane to get to the line. It is well worth the effort to cut slow and methodical keeping your saw blade close to the lines. Also, a nice sharp carbide blade is well worth the expense.



    Heres the bottom panels cut out, almost ready for glassing. I like to take both panels still clamped together and lift them up on top of three saw horses with 2X6's laid on top of them... for easy access to the edges with my belt sander for a quick smoothing of all edges.



    More to come later... Next... filling screw holes and fairing of panels and then glassing both sides of each panel with 6 oz fiberglass cloth prior to "stitching up in the cradles". Note: the panels are cut out on the nice level floor simply due to keeping the two panels tight together is easier without any twist. The next steps of glassing the hull surfaces will be done atop of saw horses with 2 X 6's laid atop them... for an easy working height during the glassing operation.

    RodB
    Last edited by RodB; 03-01-2010 at 04:54 PM.

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    Default Re: John Henry... Easy scarfing and glueup

    Heres the side panel just about ready for glassing... the bow end forward...



    My favorite scraper on a panel joint... Never underestimate the value of a good sharp 2" scraper. I especially like this one because you can pull it almost parallel with the plywood you are working on... and it cuts clean like it was a "road grater" on soft dirt. When used on epoxy that is still a bit green (not completely cured) you can cut off the obstrusive epoxy quite easily and pretty much avoid most sanding where the sharp scraper blade has gone over the epoxy. The more epoxy work I do the more I reaize how valuable the paint scraper is. I especially use it alot on fiberglass boat repair. If you epoxy some glass over a repair, the scraper flattens everything PDQ and minimizes sanding. Note: you can sharpen this scraper it in a minute or two with a small bastard file and its ready to go right on cutting clean. Always keep that file handy, cause a sharp scraper performs the best.



    A smooth sanded joint only needing the screw holes filled before glassing... I use a small straight edge laid across the joint to insure I do not creat a "dished out area"... ie., keeping the panels flat.



    Side panel ready for glassing...



    My friend, Marik, holding his bottom panel for size reference...[ Mark helped me alot on my first boat]... Reminder... the bottom panels are fabricated from Merranti, the side panels from Okoume... all from World Panel in Miami.



    All the panels of the boat waiting for glassing later this week. Waiting on a few gallons of System Three...



    More to follow soon...

    RodB
    Last edited by RodB; 03-01-2010 at 05:01 PM.

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    Default Re: John Henry... Easy scarfing and glueup

    I hope you will keep your photo essay going to completion, sounds like a very interesting design and your doing a great job.

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    Default Re: John Henry... Easy scarfing and glueup

    Thanks... more to come soon.

    R

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    Default Re: John Henry... Easy scarfing and glueup

    Quote Originally Posted by RodB View Post

    Many stitch and glue designs simply recommend using 4x8 ply panels cut the long way to fabricate bottom and side panels from 8 foot sections. Some designers recommend cross cutting 4x8 sheets of ply and scarfing enough 48" long panels together to achieve the required length of your boats bottom or side panel. This construction technique results in a much a stiffer panel and is much superior in most applications, even though it does require a bit more work. The following shows the breakdown of 3 4x8' panels so that a bottom panel can be glued together with 5 separate smaller panels of ply... You can see you end up with the required total length at the required width in a much stiffer overall panel.

    I wonder about this. Isn't plywood stronger in its lengthwise direction? So this technique would be twice as much work and the panels would actually be less stiff not stiffer.

    Steven

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    Default Re: John Henry... Easy scarfing and glueup

    I can see that the cross grain on the bottom might be an advantage for some boats, but I too can't see how that would make better sides ,assuming we want to maximize fore and aft stiffness.

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    Default Re: John Henry... Easy scarfing and glueup

    Bill and Steven...You know, I have not really explained this properly. Its more complicated than just making the panels stiffer in one orientation. I have made this edit also in the beginning of this thread.

    The multi-scarfed panels that have been rotated are really an engineering method of optimizing the natural bend of the panels to fit the panel shape in the construction of the hull. The Designer of my first flats skiff and this design, Tracy Obrien, told me long ago about this technique of fabricating panels. I think he pretty much recommends it most of the time in stitch and glue construction but it depends on the hull in question. The hull sections of the longer panels are "stiffened" from side to side across the hull with the 90 degree rotation . If you build a hull such as this with just longer sections of ply (like cutting ply panels along their 8 foot length)... the panels actually "cup" because of their increased flexability across the panel.

    As you know, plywood sheets are stiffer in their longer orientation. Rotating the crosscut panels 90 degrees allows the panels to bend easier fore and aft...thus making for easier fitting of the panels to the shape of the hull. The resulting glued up panels are stiffer across their short side (sheer to sheer), but flex easier fore and aft to fit in their intended shape. According to Tracy, this is just taking advantage of the natural bend and flexability of the materials in an engineering sense to attain the shape of the hull easier.

    Other construction techniques of interest...
    Additionally, the basic hull concept Tracy uses is a stiff panel stitch and glue hull with laminated sheer decks (with ply knees supporting the sheer decks) that "close the box" so to speak and make for very strong rigid hulls that do not torque. . . and are much lighter and stiffer than many many stitch and glue designs on the market... A most common failure point of Dorys for example, according to Tracy, was the connection between the side decks and the front deck... called a "stress riser" in engineering terms. Early in his design career, he began building continuous laminated sheer decks.... actually a "built in place glu lam beam" in order to produce a rigid hull that was able to minimize torque and "twisting stresses" very well.

    The pic below is from my first flats/bay skiff design, where I wanted 12" sheer decks... but many boats do not require such wide sheer decks... and even with say 8" wide sheer decks (as in Tracy's "Predator") ... still maintain extreme rigidity by virtue of such construction. So here is the built in place...glued laminated beam.



    After completing the sheer decks, I was simply amazed at the lightweight rigid structure of this hull... as it was turned over for additional bottom work. It was so light and rigid... truly impressive. Here, the sheer decks require about one more strip to be complete. Note, the sheer decks are laminated with 8 penny galvanized nails on four inch centers. The original strips were about 7/8" thick (Honduras Mahogany) upon installation, but were belt sanded down at least 1/8" for leveling and uniformity. H Mahogany is fantastic in how it is to work with .... no splitting, so easy to work with tools.



    How she looks now.



    The current boat my friend is building on this thread... will have sheer decks 5/8" thick (or there abouts) with 3/8" sides and bottom panels... and 1/4" panels for the rest of the bulkheads, etc. 1/4" Okoume ply will be the final layer on the decks, then 6 oz fiberglass. As mentioned earlier, the bottom panels are fabricated from Merranti so that they are stiffer and stronger simply by virtue of the material used. The side panels are Okoume 3/8". We are trying to keep the weight down on this model for ease of poling and overall reduced mass.

    Here are some rough lines... of the boat in this build.



    RodB
    Last edited by RodB; 03-03-2010 at 01:51 PM.

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    Default Re: John Henry... Easy scarfing and glueup

    Good thread,, enjoy the build.
    My take is that if you poke someone with a sharp stick they'll get annoyed, if you smile and shake their hand they will be your friends.

    John Welsford

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    Default Re: John Henry... Easy scarfing and glueup

    Heres a quick rough start of a model with the panel shapes wired together showing the shape of the hull to some degree.



    and a bit more progress... should give you an idea... Note the female cradles for the construction.



    R
    Last edited by RodB; 03-02-2010 at 05:53 PM.

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    Default Re: John Henry... Easy scarfing and glueup

    Technical construction comments added to post #29

    RodB

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    Default Re: John Henry... Easy scarfing and glueup

    Thanks, Rob. It's all clear now. Looking forward to following the build.


    Steven

  34. #34
    Join Date
    Aug 2008
    Location
    The Netherlands
    Posts
    527

    Default Re: John Henry... Easy scarfing and glueup

    Quote Originally Posted by Bill Perkins View Post
    I can see that the cross grain on the bottom might be an advantage for some boats, but I too can't see how that would make better sides ,assuming we want to maximize fore and aft stiffness.
    Quote Originally Posted by RodB View Post
    Bill and Steven...You know, I have not really explained this properly. Its more complicated than just making the panels stiffer in one orientation. I have made this edit also in the beginning of this thread.

    The multi-scarfed panels that have been rotated are really an engineering method of optimizing the natural bend of the panels to fit the panel shape in the construction of the hull. The Designer of my first flats skiff and this design, Tracy Obrien, told me long ago about this technique of fabricating panels. I think he pretty much recommends it most of the time in stitch and glue construction but it depends on the hull in question. The hull sections of the longer panels are "stiffened" from side to side across the hull with the 90 degree rotation . If you build a hull such as this with just longer sections of ply (like cutting ply panels along their 8 foot length)... the panels actually "cup" because of their increased flexability across the panel.

    As you know, plywood sheets are stiffer in their longer orientation. Rotating the crosscut panels 90 degrees allows the panels to bend easier fore and aft...thus making for easier fitting of the panels to the shape of the hull. The resulting glued up panels are stiffer across their short side (sheer to sheer), but flex easier fore and aft to fit in their intended shape. According to Tracy, this is just taking advantage of the natural bend and flexability of the materials in an engineering sense to attain the shape of the hull easier.
    Aha, so it was in the assumption maximizing of fore and aft stiffness versus maximizing "vertical stiffness". Another good example of why wooden boat building never gets boring
    When you're chewing on life's gristle
    Don't grumble, give a whistle...

  35. #35
    Join Date
    Nov 2007
    Posts
    4,992

    Default Re: John Henry... Easy scarfing and glueup

    Has anyone considered cutting on the 45 degree axis? Bias cutting...

    No seriously...I'm sure in plywood aircraft construction they use alot of plywood cut on 45 degrees. A different application I know but, and might wasteful or alot of scarfing would be needed for boat planks but interesting none the less. Anyone know much about this?

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