Author Topic: BobC's build in Virginia  (Read 5505 times)

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BobC

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Re: BobC's build in Virginia
« Reply #15 on: January 20, 2016, 07:15:59 AM »
Starbright,

To accomplish adding the chine width I had to reloft from midship aft.  It really wasn't that big of a deal.  Same could be done for the bottom panels. When doing your layout on plywood it is pretty simple to nail a batten strip an inch out from the measurements given in the book and then bend it to the point midship that the bow begins to narrow and form up.  See that the curve is fair and parallels the original curve you have drawn on the plywood and you should be good.  No need to try and measure and get exact dimensions unless you are trying to build more than one.  Just let the curve of the batten be your guide. Trace the batten, cut it out on the line and flip it over on a new sheet to cut the other side the same.  stitch the bottom together and get it in position.  Then for the chine, you can scribe the inside line of the chine off the edge of the bottom to give you a matching curve and then use the batten again to draw the outside line of the chine.  As Brian has said several times, the objective here is to retain the bottom angle and shape.  As long as you don't alter that, you should be good. 

Although I understand the concept of increasing bouyancy by increasing bottom width, it also increases wetted surface.  My objective in making it wider at the chine rather than the bottom panel was to not only to slightly increase bouyancy when at rest but slightly increase lift when running at speed which can potentially decreases wetted surface.  Whether this will work or is just a figment of my imagination remains to be seen. ;D  I suppose another method would be to create functional lifting strakes on the bottom but that gets pretty complicated.

My point here is that the 2" addition to the bottom is very easy in practice to accomplish if you want to do it as Brian proposed, it just requires one additional step to what I have done.

I don't think you will see much change in the couple of degrees the dory flare changes.

Brian.Dixon

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Re: BobC's build in Virginia
« Reply #16 on: January 20, 2016, 07:30:26 AM »
By increasing the bottom panel width, the boat will also float higher (as described), which decreases wetted surface... so I think it's pretty much a wash, pardon the pun :).  You'd keep the original waterline only if you made the boat a lot heavier.  An additional benefit is that the pounds per inch immersion (PPI) of the boat goes up with increased bottom panel width as well (more than with chines alone), so the boat becomes less sensitive to adding more payload.  But... we're splititng hairs here.  Go put the boat in a bay somewhere and ask yourself if you can see or sense any difference between the 2 methods of increasing the waterline beam... I think not.  Do what's easiest.

Brian

Brian.Dixon

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BobC's build in Virginia
« Reply #17 on: January 24, 2016, 07:46:39 PM »
One thing you have to be careful of, is the width between fender wells on your trailer. You can't make the boat wider than about 2" more without possibly having to consider taller bunks etc.  2" wider is only a fine tune... Not a big deal.

And yeah... I'm gonna be short on time for a bit here ...

Brian


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BobC

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Re: BobC's build in Virginia
« Reply #18 on: January 25, 2016, 07:54:01 PM »
If these boats get much wider, it will be like hauling a donut down the road in front of the cops....  LOL.  They already look massive enough on a trailer to make them drool about pulling us over. 

Take care of your move Brian, we understand family comes first and you have to play scarce for a while.  The weather has me in hold pattern as I have spent the last 4 days digging out our vehicles and plowing our road.  Doesn;t leave much time or energy for boatbuilding.  Now they are saying more is on the way. >:(  Trying to convince the wife that we might as well move to AK if we have to put up with this snow every year.... ;D

In the meanwhile I am stockpiling my supplies and studying my plans.


Brian.Dixon

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Re: BobC's build in Virginia
« Reply #19 on: January 25, 2016, 09:24:28 PM »
Re move ...yeah, I haven't had a day off in a month.  You can't believe how much  work is generated by moving out of Alaska.  I start the new job a week from today and still have much "settling in" stuff to do at the house that we're renting... I'll need to go back to work just to get a break!!

Brian


BobC

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Re: BobC's build in Virginia
« Reply #20 on: April 08, 2016, 11:54:21 AM »
I figured I would post an update although progress has been very slow.  Apart from doing a lot of playing around with the shearline and visualizing different cabins on them using some temporary framing, I haven't checked off much on the progress list.  As it stands right now, I have the keel and chine seams taped and the bowstem shaped and fitted ready to be glued in.  I have the shelves cut.  As soon as I get my LVL's and get them cut and on the jig, I will be flipping it and finishing off the bottom.

I wanted to mock the sides up before flipping as it is hard to picture what it looks like rightside up when it is upside down :D.

I hope you can forgive me Brian for altering the shearline.  I know this is somewhat blasphemy to mess with a designers lines.  The GA is a fine looking boat as you have designed it, it is just a little less usual here on the East Coast so I am considering this as an alternate styling on my build and wanted to see what it looks like before committing anything to wood and epoxy.  I can't get a full straight on side profile picture do to space issues but perhaps this gives a general idea.


Brian.Dixon

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Re: BobC's build in Virginia
« Reply #21 on: April 10, 2016, 07:44:15 AM »
Wow... I've never seen someone go to that effort to mock up the sheer line! But it looks great, and no, I don't have any issues with you enjoying some latitude in making the  sheer line what you'd like.  That's what is called a "powderhorn sheer" and they're very popular...


Brian

starbright55

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Re: BobC's build in Virginia
« Reply #22 on: April 10, 2016, 09:43:25 AM »
Bob, it looks great.

How are you going document/memorialize that sheer so you can flip it over? Just frame/brace and flip it as one piece?

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BobC

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Re: BobC's build in Virginia
« Reply #23 on: April 11, 2016, 07:54:46 PM »
thanks guys. OK, so the framing is only temporary to hold the shape in the shear for visualization. Each location is marked using index markes on the chine and shelf and numbered as well as measurement taken and logged.  (I take these measurements on the shelf at diagonals from a fixed point at the tip of the bow so both sides are symmetrical)  It will be removed before the fairbody is flipped upside down.  After the fairbody is flipped , then the framing will get re-installed (just a single screw at the chine and the shelf on each point) which holds the shelf in place until the sides are hung, scribed cut and epoxied in place.  Then I will remove the screws and framing pieces. Then I can glass everything before flipping it back right side up and then put in the correct stiffeners.  Of course this is if everything goes according to plan... :)

Glad to know this is called a powderhorn shear.

Easygoing

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Re: BobC's build in Virginia
« Reply #24 on: April 14, 2016, 11:43:55 AM »
Looking good, Bob.  Thanks for posting...

Ed Snyder

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Re: BobC's build in Virginia
« Reply #25 on: April 15, 2016, 08:45:01 AM »
Love the sheer shape Bob!  :)
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BobC

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Re: BobC's build in Virginia
« Reply #26 on: May 05, 2016, 10:00:32 AM »
OK guys here is a little update and sneak peek at what I have been brewing.

I went ahead and cut out some side panels and put them on the mockup to see what it looked like.  I liked it pretty well but it screamed for just a litlle bit of flare and curve in the bow portion to go with the change in the shear. 

To achieve this, I cut the panels just a little large.  I snapped a chalk line from the bow to where the rise in the shear begins. Then I built out the edge of the shelves starting where the rise in the shear begins by laminating some strips of wood on in about 1/2" increments until it extended about 5" further than stock at the apex of the curve.  Then I made a series of vertical cuts in the top of the panels  to allow them to fan out as they are bent around the boat and to form the flare along the top edge.  I have a few adjustments to make at the bowstem and a little trimming to do after I scarf the panels together. Here is the result for the side I did the template on...
 This is not permanent, just trying on for size so I can stand back and look at it right side up, and see if I like it before I flip it upside down and do everything inverted.  My mind doesn't work well upside down.  My other thought on this is by using a template, I have reasonable insurance that both sides will be symmetrical.  I know this is a lot of bother for mostly just aesthetic purposes but I'm still a couple weeks out on having the funds to buy all the glass I need so this is filling time and keeping me busy.

starbright55

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Re: BobC's build in Virginia
« Reply #27 on: May 05, 2016, 10:55:58 PM »
The Carolina GA!

Are you going to adjust the bowstem at the top to account for the flare?

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Brian.Dixon

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Re: BobC's build in Virginia
« Reply #28 on: May 06, 2016, 05:36:52 AM »
Now that is cool!  Lots of ingenuity there...

Brian


BobC

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Re: BobC's build in Virginia
« Reply #29 on: May 06, 2016, 06:46:42 AM »
Starbright,

Yes, the bowstem gets adjusted.  It is leaning forward a little bit too much and is about 3/4" too short.  I need to angle it up a little steeper and then I will be putting a peice o 3/4" ply on top of the bowstem to fill the gap created there.  The ply will overlap the bowstem on both sides to provide additional surface for tying in the shelves and to reinforce the prow of the bow.  Putting the flare in the side places a lot of pressure on the shelves so they try to do squirrely stuff like twisting.  Increasing the glued surface area at the front will make everything go together easier and ensure a proper alignment. and strength.

Brian, I don't know if I would call it ingenuity or stupidity.  Some think I am making headaches for myself and destroying a perfectly good design while others think it is really cool looking.  I don't know if its right or wrong but it looks good to my eyes and I have never seen anything quite like this done on a S&G design or anything in the Tolman genre. Anything I have seen S&G is always flat simple curves. I have only seen compound curves using cold molded methods or plank on frame.  What I have done so far is very simple and seems to work very well.  I am planning to reinforce the backside of the cuts overlapping some strips of 1/4" ply, sort of like using the Ashcroft method.  This will hold the flare in the piece without the need for internal framing.  Then I can fill the small cuts on the outside with thickened epoxy making sure it is all fair before putting the glass skin over it. 

It's really tough to show what it truly looks like in photos as I can't get back far enough and my focal length is too short to show the curves without distorting it all.

At this point the only challenges I see are the number of screw holes I have created will require a lot of filling and it will be slightly more difficult to fair than if it were flat. ;D

If it doesn't work out, I can always cut it off with the Recip saw and go back to stock profile as everything to this point has been built up from stock and could be dropped back down.