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Choosing A Boat/Plans

Posted by ozarkdrifter 
Choosing A Boat/Plans
June 17, 2019 02:05AM
I'm at the absolute beginning, trying to sort through the research stage, and figured I'd get some guidance right from the start in choosing the right plans for me. This will be my first boat build, and will be aided by my dad, and my thankfully (and hopefully) more qualified engineer brother. I'm based in Arkansas and spend all my free time fly fishing our tailwaters and small creeks/rivers for trout and smallmouth bass. 95% of the boat's life will be Class I/II water - a fishing boat first and foremost. I suspect I might pull it west at times, but generally wouldn't challenge water more than Class III and with that rarely. I've browsed the forum for a while now, and there's a few things that have become evident as "general consensus" I plan to heed. I want to use proven design ideas, as this is likely to be a long term project with long term use. I suspect with regards to consensus I'll try to use 3/4" Plascore for the bottom of the hull and 3/8" Meranti Hydrotek for the side panels. Our tailwaters in low flow, as well as our small creeks/rivers are shallow, slow-medium in speed, and do contain a fair bit of rocks. I currently row a Hog Island skiff with a Yamaha jet outboard. I'll be keeping this as it's an ideal set up for our tailwaters, but for low flow days and overnight smallmouth trips I'm interested in building my own boat that would be lighter with a shallower draft. And I smash quite a few rocks in the Hog..... While a skiff such as a Freestone would seem to make sense, I'm drawn to the lines of a more traditional drift boat, as well as we fish standing up 100% of the time and casting braces will be part of the plan. Looking through plans, the Kingfisher (or in Recurve style) is beautiful but a bit large for our smaller waters (maybe a second build.....). The Beavertail seems to be the right choice for me in that we will almost always fish with 3 (2 anglers/oarsman). I have looked at Cajune's Classic Guide, which appears to be similar in length but widened to 55" or so. I guess my question is this: "general consensus" also seems to be wider is more stable - should I choose a wider design such as the Classic Guide? I'm not sure if it's more of a design akin to the HD that won't trim well with a rear seated angler. If that's the case should an attempt be made to widen the Beavertail? I suspect that would distort the design and rocker and could get over my head. My dad is prone to enthusiastic casting....so having the wide bottom (54" on the Hog) has been handy. I have no doubt I'm overthinking things I know nothing about, but bottom line am in search of a stable not too heavy drift boat capable of rowing well with fore and aft anglers - you know, the Holy Grail! Thanks in advance for any advice, I'm excited!
Re: Choosing A Boat/Plans
June 17, 2019 12:25PM
RE "If that's the case should an attempt be made to widen the Beavertail? "

That would be fun project. I design all boats using adjustable ribs that hinge at the corners and spline in and out at the middle.

Make side panels with layout lines are regular intervals, with one such station in dead middle.

Make a stem.

Make a transom.

Fiddle with it until it looks right.

Straighten it up. Don't miss the straighten step. It is critical.

Put a square edged bottom panel (with center line top and bottom matching vertical centerlines on the trapezoid formers) on it and weight it down with buckets and tools. Trace out the edges. Take the bottom panel off the plug and cut to the line with a slightly slanted angle on the skill saw.

This is a blurry cell phone photo but it does show a typical adjustable rib-like former. Made from flake board.






If you made the middle rib-like trapezoid 56" inches or so wide (make that fixed trapezoid from chip board) the rest is just messing with it.

Designing with software is useful but you still don't know what hull will really look like until you mock it up full size. So software isn't worth that much. I'm a retired programmer. I did 3D data modeling with OpenInventor and OpenGL on expensive Silicon Graphics machines so I'm not intimidated by software. For me, for boat hulls it just isn't worth the hassle because I know I'm going to mock it up full size anyway, so I can REALLY see what it actually looks like. I always tweak it repeatedly. Walk away. Think about it. Mess with it some more.

Then one day I look at my full-size mockup and say "That's it." And then I make a boat out of it. Software be damned.
Re: Choosing A Boat/Plans
June 17, 2019 06:12PM
I require assistance for faxing......so I'm with you on the software vs. mock up. I guess if I were to widen the Beavertail to 56", the side panels would need to be lengthened or dished out to keep the rocker from becoming too steep and shortening the boat considerably. That's where the mock up and adjustments would come in handy, adjust here & there and see. Would like to keep the panels to 16' so probably means a little dishing out and transom widening. So with the "Classic Guide" on Jason Cajune's website, is that basically what he's already done or is that more of a Honky Dory / MacKenzie style boat that won't row as well with an aft-seated angler? I'm not opposed to some experimentation, but as a first time builder and long time dummy I need all the help I can get!!
Re: Choosing A Boat/Plans
June 17, 2019 07:42PM
Jason's a cool guy who makes excellent boats. But I've never actually rowed any of his boats so I can't answer any questions about them.

The Beavertail as it is does not have a dished out chine. It does have a symmetrical bottom so it does trim well with a rear-seated fisherman.

If you kept it the same length but widened it mostly in the middle it would be a new boat, new design. You probably would have to dish the chine some. For a first time builder you might be better off building from fixed dimensions. I built my first boat from plans. And then went to DIY from there after.
Re: Choosing A Boat/Plans
June 17, 2019 08:47PM
Much appreciated Sandy. That's where my head was too, building from set plans as to not get into a new design element and get in over my head. The Beavertail continues to sound like the right boat for me considering the proven design to accommodate the aft-seated fisherman, as that's critical for how I typically fish. Thanks again for all the advice!
Re: Choosing A Boat/Plans
August 19, 2019 01:03AM
I've spent the last two months "building" the boat in my head....so I've taken the next step and have constructed a full size model. Made some practice scarfs (ugly but functional) and actually got a boat out of it! Will have to get some pics up soon of the model. I built a full size 15' (14' 6") beavertail side panel + transom which gave a nice shape, and still is a likely final landing spot. Playing with the model I expanded the midsection from 48" to 54", and proportionally increased the beam as well. Around 78" I kept the same transom and stem angle, again just playing with different widths. This led to the discovery of the limits of my scarfing - and math abilities. Cracked the top of the scarf on one side. As expected the rocker shot up on either end, by 4" at the stem and 3" at the transom. My plan to play with the design further is as follows: Dish the chine for the full length of the panel, 2" at the mid-point. I'll have to start with taller side panels I suppose if I end up dishing them much more than that just to keep oar lock height (?). Widen the transom up a bit, and steepen the stem angle slightly. My thought is this should reduce some of the strain on the (relative to width) short side panel and allow for the wider mid section. Shooting for a symmetric enough bottom to fish a rear seated angler well and keep the transom out of the water - the beavertail's absolute claim to fame.

I suppose this is the time to ask - am I barking up the right tree? Logically this seems to make sense, but in practice it may be another thing all together. Very open to any suggestions for ideas of what to tinker with next.

Another question on rocker, a reduced rocker seems to be in order for mostly flat Class I-II water which is the bulk of what I fish. Some is fast and skinny with lots of rocks, so floating high is paramount. In my head I seem to think, the less rocker the more surface area, the shallower the draft, but is there a minimum rocker height at the transom to keep it out of the water and back-rowing well? My logic says this is based on boat weight, hull shape, total rocker profile, etc and will vary boat to boat.....but worth asking I suppose. An altered chine dish allowing for a flat middle section and more rocker at the stem & transom might remedy that, not really sure.

Sandy I appreciate your previous instruction - I put down the calculator and tape measure so to speak. The boat can be as long and as wide as you want it to be - it's all just a matter of playing around with the profile, and it's fun!

Thanks,

Brad
Re: Choosing A Boat/Plans
August 19, 2019 12:10PM
Wow. I just got up and my brains are not switched on yet. I'll respond more eloquently later today. What you've done is great.
Re: Choosing A Boat/Plans
August 19, 2019 12:44PM
In this case, with the rocker being increased, could it be that you have the option to lower the sides and the rocker by 2 or 3" each? I wonder if that would be better for your milder AR rivers and off season breezes.........sort of a western looking boat but with midwestern side height and less rocker?
Re: Choosing A Boat/Plans
August 19, 2019 01:09PM
That's the plan. The super pronounced rocker angles were expected, just toying with the model. Next step will be to maintain the extra width and find an appropriate rocker profile for the ozarks, but keep the caboose out of the water with 3 dudes, a dog, and enough gear wage a trout war!
Re: Choosing A Boat/Plans
August 19, 2019 01:18PM
Actually Ill watch the dog for you, lol. one of the main reasons I don't care for Kayak fishing is that my best buddy can't be with me in comfort.


I'm quite interested in how you make out, the seating choices, knee braces, type of oars and locks and rocker profile. Watching!
Re: Choosing A Boat/Plans
August 19, 2019 06:13PM
RE> minimum rocker

The flatter the boat is the higher it floats and the harder it is to turn.

You also need enough rear end (upstream end) rocker to keep the transom out of the water no matter how it is loaded. If the flat part of the transom sinks down far enough the current pushes up against that flat transom and then you cannot slow the boat down.

Ray Heater used to say you needed at least 10" inches rocker at the rear end, as in 10" inches to the bottom of the transom when the boat was sitting on concrete in approximately the same posture as it floats. For Ozark rivers you might get away with 8" but not less I don't think. 8 - 10" inches isn't the whole story however. How flat is the boat in the middle? Does it rise up quickly, near the rear end, to attain that 10" inches or does curve gain gradually from the middle out? I like almost but not quite flat in the middle 3 to 4 ' of the boat with gradual rocker, while maintaining as much width as possible, all the way out to the ends, with sharp bends at the end, creating lots of rocker far away from the middle. Looking at a full size model tells you a lot. It's one thing to write sentences about how it all should work. When you look at a full size model sometimes the corners of your mouth go down because it just doesn't look right. Other times you find yourself smiling. That's how I design. My goal is to smile twice: once at the model and one more time when I first row it.

You need some downstream rocker too but you don't need as much. Less front end or downstream end rocker does not have the adverse side effect of making the boat impossible to slow down. But you do need some rocker, else the boat is slow as molasses to turn, which can be a safety hazard in a boney rock garden with fast water in between the rocks.

How much front end rocker is just right? That's hard to answer. When you are designing a new boat nobody has ever built before you have to take some chances. Risky behavior sets real boat designers apart. :=)) We are a reckless lot.
Re: Choosing A Boat/Plans
August 20, 2019 01:17PM
Still fiddling with attaching pics, but on my "by the book" Beavertail model it had a lovely gradual rocker beginning right from the center balance point, about 10" at the transom (upstream). It looked balanced as if it would turn on a dime, without much "flat spot" to speak of. Any recommendations to building in the almost flat spot in the model? A modified dish comes to mind, in that either it doesn't run end to end, or is flattened out a bit (but not completely) over the middle 4 feet?
Re: Choosing A Boat/Plans
August 20, 2019 02:27PM
Attaching photos with this forum software often fails, usually because the images are too big. If you have an image editor scale them down to 500 or at most 700 pixels wide and try again.

Or send your images to me as email attachments and I'll put them into the thread. You are doing interesting work. I want to see it. One way or another.
Re: Choosing A Boat/Plans
August 20, 2019 03:06PM
Fancy boat hull design software like Rhino can do lots of cool things. You can make a 3D model on screen and spin it around. Look from below. Look from the side etc. It will show the water line without load. It can calculate the boat's center of gravity. I wish I had Rhino. But it's close to a thousand bazucks.

You can guess the center of gravity, close enough, by staring at a full size model long enough. The placement of rower and the oarlocks should be made so the rower's attempt to spin the boat naturally coincides with the boat's center of gravity. That center of gravity changes with different loads (two people? three? camping gear?) so this isn't an exact science. But it's useful.

I have a 12 year old boat I built with a relatively flat bottom. It was an experiment. I wanted a flat bottomed boat I could use with my 20hp two stroke 1981 Mercury outboard. And also row on the river. And also so it had the pointed end facing downstream. It was a failure. Bad experiment. I should have built a Rapid Robert, where a large square transom faces downstream when you row (like a Buffalo Boat) and where you turn it around 180 degrees and put the outboard on the big flat transom, when you want to motor.

Failed experiments are useful. You live and you learn. It's still a good boat. I use it a lot, although mostly with the motor. On rivers, because of its flat profile (It does rise up 10" at the transom end, but is relatively flat the rest of the way), it has too much chine in the water and it's very slow to turn. One interesting side effect, however, is that of all the boats I've ever built it is the easiest to slow down in a current. The transom does rise up out of the water, so the downstream push from the current slants down under the boat instead of pushing hard on the transom. The relatively flat profile the rest of the way creates minimal drag or friction in the water. On tailwater rivers where there is no need to turn quickly it's a great boat, because I can dead stop it anywhere I want, while someone else pounds a holding spot. In fast boney water it's a liability. It's too hard not to crash into the rocks.

Everything is a tradeoff. Optimized here means not so good there. The perfect boat for you amounts to the best compromise set for your particular goals and priorities.
Re: Choosing A Boat/Plans
August 20, 2019 06:20PM
I'm gonna send you some pics via email. More to come after Wednesday evening. Will play with transom dimensions, maybe side panel dishing then.
Re: Choosing A Boat/Plans
August 20, 2019 09:00PM
This damned forum software seems to be broken. It would not attach these images even after I made them smaller.
I'll work on it. In the mean time I added Dan's photos in a more manual way.






Re: Choosing A Boat/Plans
August 20, 2019 09:05PM
What I notice:

You only have one set of spreaders in the middle, which makes a nice gentle dory-like shape with stem and transom tacked on too.

If you add two more spreaders either side of the middle you can warp that curve a lot, so for instance it might be a lot more flat in the middle (by maintaining most of the width for at least 2 feet either side of the middle). Then it would bend inward and upward sharply at the ends.

That would make a better boat, especially for the semi-placid Ozark waters you want to drift.
Re: Choosing A Boat/Plans
August 20, 2019 11:16PM
Extra wide up front is particularly important for white water, which isn't your context. I know. But it is worth mentioning.

My HD is extra extra wide as far forward as possible. It is that way so much it's actually a bit tricky to make the plywood bend. A few builders have tried to make the Honky Dory with 3/8" inch side panels and broke them trying to force that radical bend up front. The way to make 3/8" bend that much is to wet it first. Put wet towels on the plywood over night, before bending it on. That isn't necessary with 1/4" side panels but it is with 3/8" panels.

Anyway that much width way up front makes a boat that climbs up on the waves instead of punching into them. Larry Hedrick built a custom boat based on the HD. He stretched it out longer without making it wider. And he pulled the stem angle in, which made it easier to bend the sides on but he got extra rocker up front because of it, and lost a bit of width up there too. He's got a very cool boat. I've rowed it. I've gone river tripping with Larry, several times. Larry has done the Grand Canyon in that boat. And he is quick to say he wishes he could have that extra front end width back. He'd rather have the boat walk up on a wave, rather than knife into it.
Re: Choosing A Boat/Plans
August 21, 2019 02:37AM
Thanks for getting the pics up! Great point about the additional spreaders/formers to modify the shape, will tinker with that a bit and see how she looks. Makes sense how to maintain similar shape for mid section to flatten things out. I recall reading a thread here about the front of Larry's boat and how it handled differently. Will toy with shape via more formers first. May try a slightly upsized/widened transom too just to see what we get. Then fool around with chines. Very good insights as always. Thanks, will see how it goes tomorrow night.

Brad
Re: Choosing A Boat/Plans
August 21, 2019 01:45PM
What plywood is that? It looks like something better than AC construction plywood. Where did you get it?
Re: Choosing A Boat/Plans
August 21, 2019 02:07PM
Sandy I found that if I sized them to 800-900 KB they will always attach. Once I go 1 or 1.1 they won't.


Here are building questions:

-Why not use more regularly spaced frames......say every two feet?

-And why not incorporate a Sternpost? A sternpost that carries into a keelson would allow you to incorporate a veebottom. A vee bottom of only 2-5degrees wouldn't change the draft much and along with the rocker, which goes the other way, would help you spin faster and make the hull stiffer and stronger.
Re: Choosing A Boat/Plans
August 21, 2019 03:50PM
Some of my designs go back to the early 1980s. When I design now I start with a former dead middle of the side panel layout and then work left and right on 2' foot centers. Former locations are arbitrary.

I don't know what a sternpost is.

A slight keel warped or even sharply formed into a dory bottom is something I've wondered about, but never fiddled with.
Re: Choosing A Boat/Plans
August 21, 2019 06:08PM
Will be adding more formers this evening for modeling. This was rapid tinkering for proof of concept and "baseline measurements." Plywood from our local hardware shop. Finished one side not on the other, $20 per sheet. 3/8"
Re: Choosing A Boat/Plans
August 21, 2019 07:12PM
That cheap plytanium 3/8 is what I built this whole boat out of. Keep going.
Re: Choosing A Boat/Plans
August 22, 2019 03:27AM
Model update: Beavertail side panels & transom standard dimensions, stretched at middle to bottom width of 54", beam of 74". Two more spreaders placed 2 feet either side of middle. Was not able to bend the 3/8" ply at the stem with additional spreader set proportionally larger from original Beavertail former dimensions, will take some custom tweaking. This left me with a WIDE hull shape for length and a mostly flat center section. 11" of rocker at stem and transom, 14' 2" in centerline length. Looks mostly good, but not quite there. Some tweaking of spreader dimensions a bit more. I like the "curves" of the shape in the rear half better than the forward half - so will be tweaking to obtain some semblance of symmetry - though I realize it won't be symmetrical. At this point question to answer is do I bother dishing the chine with that rocker profile or call it good and run with it? Betting I keep tweaking it.......

Sent some pics via email to you Sandy. Even tried 40kb, wouldn't attach for me - this is no doubt operator error on my part and I'll be seeking IT counsel tomorrow.
Re: Choosing A Boat/Plans
August 22, 2019 03:54AM
Perhaps not kpetator error. Some is busted with this forum softwear
Re: Choosing A Boat/Plans
August 22, 2019 11:01AM
"Seeking Counsel", you're suing? lol.
I'll be interested in how you reduce rocker. Specifically that is. Are you doing it on paper or tracing lines on the model? how do you arrive at the final rocker?
It would seem that in operating drift boats that the rocker isn't needed until its needed and by then it is really needed. I really like some of the very low-sided, low-rocker boats I've seen but when conditions worsen there appears to be nothing in reserve. My only experience with this shortcoming is with canoeing in which case a deck would have saved the day but instead I went swimming.
Re: Choosing A Boat/Plans
August 22, 2019 11:06AM
Would 1/4" ply bend easier. I saw on set of plans that allowed the use of birch ply. I'd have to be sure what glue is used before I'd try that.
Re: Choosing A Boat/Plans
August 22, 2019 11:37AM
Re: Choosing A Boat/Plans
August 22, 2019 01:32PM
Counsel. Council? I dunno. 1/4" would bend more easily, but considering the strikes on my current boat I thought 3/8" a tad better. I may not end up reducing much. 11" not too bad in the back. Would like a little reduction up front. Currently like a wind sail. I see your point with low sided boats without as much reserve, however not much of an issue here, plus wouldn't likely float afar with it on anything more than class 2 waters. We utilize low sided skiffs here often with no issue. Though an eye to safety is never a bad idea. I may still have to dish it some, will see.
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