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Messing about with boats

Posted by Sandy 
Messing about with boats
January 14, 2016 11:11PM
Got back to the shop for the first time in a month. Yesterday and today. This is a first pass at putting 18' foot long panels onto a set of adjustable ribs. One side photo and one of the stem area. The stem shot shows how a notched block on the outside connects back to the middle with a wire and a turnbuckle, so I can pull the front back to the middle, which helps bulge out the middle. Same deal at the rear end where a turnbuckle connects the transom to the middle, thereby bulging out the middle some more.

Then I fiddle with widths and side angles until it looks right. This boat has a lot of side flare below the oarlocks. Lots of side flare has a tendency to make too much rocker. There are at least four things you can do to reduce rocker, all of which are in play here. One is to dish out the chine so the chine edge is not a straight line. This chine is curved from 4" inches up at a spot about 12" forward of dead middle to nothing at the front and rear ends. Second is to keep the boat as wide as possible in the middle, so the mid-section has almost but not quite parallel chines--and keeping that width as far forward and back as possible without breaking the plywood. Third is to warp the side sheets a little, so there is a lot of side flare in the middle but less fore and aft. Forth applies to the upstream end only. The wider the transom the less rear-end rocker the boat has.

This form is 63" wide in the middle. By the time Plascore goes on top of this form the widest distance across the bottom will be approximately 65" inches. With 30' degree side flare the oar locks will be approximately 7' feet apart. Exactly how high to place the rower's seat with 10' foot oars will have to get worked out on the fly, later on.

There are no set rules about rocker. Ray Heater once told me he likes to have 10" to 12" inches rocker at the transom, for a 15' foot boat, with either the same or a little bit less up front. This is a 17' foot boat so those numbers go up a bit. I currently have 13" inches rocker at each end ( I have a 20' foot board hanging from the ceiling, parallel to the floor as a reference ). I might live with that. I'll have to look at it for a few days before I'm ready to button it up, cover it with Visqueen and then attach Plascore on the outside of the form.

And do it to it.







...........I'm going to round off the lower edge of that transom some, perhaps on a 16" inch arc. Many of the molded fiberglass boats are built that way now and I give credit were credit is due. A sharp edge at the transom pushes water too often. A wide radius round off is better design.




Re: Messing about with boats
January 21, 2016 03:19AM
Sandy,
You are not getting much feedback because everyone is waiting patiently for your next move. This is an exciting boat build...!!! Chop-chop!! ;-)
Re: Messing about with boats
February 04, 2016 07:17PM
Spent yesterday back in the shop again. I'm almost ready to call it a hull. The way I work out a new design, using a full-size model with adjustable ribs that spline in the middle and hinge at the sides is a bit frustrating and time consuming. The idea is to fiddle with dimensions until it looks right and then call it a boat.

But when you have a hull shape (like the photo above) that is widths and side angles only the chine curve can still be wacky--because the adjustable ribs are not straightened to a center line yet and/or are not parallel to the floor. After you begin to straighten it all up you almost always find you have to go back to square one and make a few more adjustments.

Next time I do this I'll have it. 17' feet long. 63" inches wide under the oarlocks. Almost but not quite flat in the middle. Lots of side flare--under the oarlock pins anyway--and the width extends out to the ends as far as possible, which requires sharp last-minute side bends fore and aft, as much as the form plywood can stand without breaking. Cover it with Visqueen. Cover it with Plascore. Fiberglass it up.

This forum used to average 5-10 posts a day. There was a time when this was the only forum around. I started it in 1998. But then a dozen or more other boat building forums popped up. And then Facebook and Instagram came along. And then I largely retired. So I didn't have all that much to say anymore. And now I get 5-10 posts every three months or so. Inneresting. But we're not dead yet.

I go to California for ten days soon. When I get back I hope to get my ass in gear. It's not an easy thing to do.....to get me to actually work anymore. But I'll work at it.



Re: Messing about with boats
June 06, 2016 11:32PM
Why did you dish it out? Locks 7 feet apart? What is it that you are after? Is the goal to build something which can carry enough beer for you and Dave? That would be some quest.

What do you do with all these boats? Do you try them out a season then sell them to try another shape?
Re: Messing about with boats
June 07, 2016 02:01AM
Yes it's important to sell the damn boats so you can build another one. Doesn't that make sents?

This boat has a lot of side flare. A straight line chine on a boat like that would look like an extra-crooked banana. Side flare really juices the bottom rocker. I wanted to bring the rocker profile back to normal......................and still have all that side flare.

Is this boat really so wide? Or are most other dories too narrow? It is not all that wide compared to many a raft. It will float high. It is wide and flat in the middle so it will be stable. I'm a sure of it. And yet it will still turn easily. That's the goal anyway. Float high turn fast. And still be stable. No annoying constantly sea sick side-to-side tipping like on the Briggs.

The Briggs and many others have a 4' foot dead flat spot in the middle, with parallel chines. Don Hill was a big flat spot guy. This boat has very little rocker in the (four foot) middle. But it does have some. That helps make a well defined turning axis. Four feet of dead flat makes a boat that doesn't know where it's middle is.



Re: Messing about with boats
August 30, 2016 10:24PM
Sandy,

I haven't been on the board in quite a long time. I have been engaged in many non-boat related projects in the last 8 months, but I have finally cleared out my shop, re-surfaced my work-benches with plastic and actually epoxied my first scarf joint!

I am adding this post because I want to tell you how valuable I have found this board in the past in giving me the confidence to embark on this project. I actually started my project 2 years ago and it may, indeed, be a factor in my recent divorce (I'm a project person, I also built my ex-wife a barn and horse facilities and two garden/greenhouses, but she never considered those). The other main factor in my divorce, in reality, would likely be fly fishing, so you can see I was indeed married to the wrong person and now I am happily single, broke, unemployed and partially delinquent on my back taxes. This is the perfect time to complete my boat. Luckily, I have most all of the materials already purchased except for another 3 gallons of epoxy and whatever I end up using on the bottom of my wood (not plascore, sorry, long story there, but I read nearly every debate on this board about it and decided on wood).

I'm building a Kingfisher with plans purchased from Jason, but I may decide to drastically change the interior based on a few recent topics about wide gunnels and boats built with convertible decks that slant to the outside (Like old Lavros, brilliant). I can't wait to find your discussions of your 1-man dory project.

I plan to post photos of my project, after I find my original posts where I posted photos of my seat pedestals. I hope to receive some comments/suggestions, as I will likely be asking questions as well. I know most every question I could come up with is on this board, so maybe people will at least direct me to how to find a particular subject.

As to your current project, I love it! Yes, wider/flared more is better, that was the central design point of a dory I thought, more cargo, more stability, that and you had to be able to stack them on deck. Rocker would be an evolution we needed so the boats could be maneuverable enough to navigate shallow rivers. Of course, that sacrifices tracking ability, perhaps very important when fishing and needing to row upstream to keep fishers closer to their quarry or to allow more casts at the shore when enticing browns from the shallows...how about a sculling oar mounted on the transom that can be locked down/up, with a removable shaft for when you actually want to scull, or even better a yuloh, but that's a huge other discussion. A good oarsperson with open oar locks and no "oar-wrongs" can feather oars and keep straight anyway....

Wish me luck!




Me: Do they take that as a mayfly or a caddis?
Willie: I don't know, I never asked them.






Re: Messing about with boats
August 31, 2016 01:13PM
Interesting. So it looks like the Kingfisher has a substantial flat spot in the middle of the boat.
Re: Messing about with boats
September 01, 2016 03:19AM
I enjoy floating downstream with my upstream oar in the water and sculling to maintain my position. I think that a yuloh would be fun to try too.

Rick N
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