Assymetrycal Semi-V Design

[swampwood]

Hello everyone,
Need your inputs as to how you might think this design will act in the water? (tracking, wind, paddling and stability)
I am fixing to start my cypress strip kayak ( 17' Endeavor by Bear Mountain ) build and will be working on this design (Piroque) after that.
I will be using stations 12" apart and building with cypress strips.
It will be a 16' length, semi veed starting 6' from the bow to the bow, 7' from the bow it will be 24"bottom, 36"beam and 10" depth. The sides will be 30 degrees at this point. 9' from the bow it will be 25 1/2" bottom. The boat will be pointed both ends and widest at 7-10' from the bow with the sides from 7' decreasing in degrees to the stern.
The rocker is 1" at the stern and 2 5/8" at bow.
The shape is like a piroque, (flat sides and bottom) the only difference will be the 6' of semi-vee in the front.
I plan to fiberglass the hull in and out. Don't plan to add ribs, unless needed for strength.

 

[Kayak Jack]

I didn't read anything about rocker, but it sounds like a strong tracking design. Probably will not maneuver well in a tight, winding river. Wind affect has some other variables. Anything lashed or bungeed to the top decks will catch wind and affect handling.

Stability can be more the paddler than the boat, but the boat has a strong effect too. A semi-vee bottom can act like a boat with two, narrow, flat bottoms. As you lean it to one side, a flat edge will provide a shelf of stability. Further lean will overcome it and it may step off that shelf abruptly, or not, according to how the sides blend into the bottom. Slant of he sides help provide a predictable lean and final point of lean. Width from centerline provides the length of lever arm of force for the boat to resist lean, or rolling. Location of the width is relatively unimportant; amount of width is more important.

 

[a Bald Cypress]

You are looking at 75-80 lbs. Not a lightweight.

It should be very stable and I agree [unfortunatly] :? with Jack. It will be hard to turn.

 

[swampwood]

Thanks for the replys, Kayak Jack & a Bald cypress
I added to the description and hope it clears up some of the confussion about the design.
I agree with Jack about the semi-vee. It will be like 2 flat bottoms untill it meets the bow, but I do not see it affect the stability because it is only 6' in length and at the front of the boat.
Hoping it does help the tracking?
The width is 1' forward of center and I am trying to keep it as wide as possible from that point to the stern.
Hopefully I can keep the weight around 50 lbs.

 

[Jimmy W]

Will it be decked or open?

 

[swampwood]

It will be open!
It will look like a piroque, except for the semi-vee in the front 6'.

 

[Kayak Jack]

A comment on asymmetrical rocker. I think it's a myth. Boats settle to their lowest point. Unless you load a boat asymmetrically, your rocker in the water will be symmetrical. If you want rocker to be asymmetrical, load a boat to trim our nose high or nose low. Not all will agree with me.

 

[jdupre']

Not that it would make a tremendous difference in the behavior of a boat, but I think assymetrical rocker can make a measurable difference. Take the average kayak, whatever that is. If you trim the bow down, past it's designed waterline, you increase the width at the waterline by a small amount dure to the flare of the sides. Same with the stern. Increased width at the waterline translates to more resistance. Not gonna make too much of a difference for the average tourer, but a racer would surely take that into consideration.

Joey

 

[Kayak Jack]

I agree, Joey. But, beam and flare are separate from rocker. Each one becomes related hydrodynamically, but each one can be varied separately by a designer.

 

[oldsparkey]

Not sure about all of the technical things you are saying...... It just appears to me that you have thought this process out and know how you want to do it.... Just like Joey did with his swamper he dreamed up and then built.

I say go for it and if it floats that is the ..... MAJOR ITEM ....Then if it is easy paddling , Even better....... and from there all it can do is to get better.

What we have in the back of our minds about the boats we want , only we know about and since none of us are boat designers ... we do enter into dark waters ..... The waters become Krystal clear when the boat does what we want , if not then back for some modifications to make it do what we want. All I can think of is an old saying ..... To Many Cooks tend to spoil the stew. :wink:

As I said at the beginning , Joey dreamed up his swamper , made it and is happy with it , his idea , his build and now his boat.

I do like the idea of a modified V in the front , it helps to cut the water in place of pushing it. Not wanting to be the odd man out on your ideas ....... All I can say is to go for it and do it your way , it will be your boat. If there is a problem ( I don't think there will be one ) then a boat designer might chime in and offer some help or even a drawing of what to do.

If you do proceed with your original idea , some decent size pictures on here would be nice. Just keep them reasonable so the dial up folks can enjoy the progress. viewtopic.php?f=1&t=3927

 

[swampwood]

I have been doing some thinking on this design and in my mind, I am thinking it should be pretty stable, old sparky and I are on the same thought pattern as too the semi-vee. I think it should cut the water better than a flat pointed bow. I see it as a keel of sorts, offering some lift and making it easier to turn than a traditional piroque. The width from front of center and running as wide as possible to the stern should give it stability.
I am not a designer by nature. This build will be a combination of things learned on this site and from things I have already learned from the build I am presently working on.
I love wood and have been working with it in one way our another for the last 40 years.
Appreciate all the info
Swampwood

 

[Kayak Jack]

Put your mind's eye vision into wood and paddle it.

 

[beekeeper]

You are looking at 75-80 lbs. Not a lightweight.

It should be very stable and I agree [unfortunatly] :? with Jack. It will be hard to turn.

Not disagreeing, but how did you calculate the weight?

beekeeper

 

[beekeeper]

 

[Kayak Jack]

It's a beautiful thing, watching a boat come into life. Curves and promises, adventures awaiting, sunsets and (if you're really desperate) a sunrise or two. Paddling distant waters, camping on far away shores, listening to catbirds, robins, chickadees, kingfishers, eagles, loons, and blue jays. Tasting a fish caught that day, sleeping nearby, ready to load up come morning and see other places. Coffee and bacon, jerky and lasagna - memories, some from already has beens, and others from tomorrows yet to be experienced.

Boats, coming to life.

 

[WDfrmTN]

It's a beautiful thing, watching a boat come into life. Curves and promises, adventures awaiting, sunsets and (if you're really desperate) a sunrise or two. Paddling distant waters, camping on far away shores, listening to catbirds, robins, chickadees, kingfishers, eagles, loons, and blue jays. Tasting a fish caught that day, sleeping nearby, ready to load up come morning and see other places. Coffee and bacon, jerky and lasagna - memories, some from already has beens, and others from tomorrows yet to be experienced.

Boats, coming to life.

Well, now....ain't you just the philos'pher! :wink:

 

[Kayak Jack]

Have cracker barrel, will travel. :wink:

BTW -a precautionary warning to all paddlers. Speaking of a cracker barrel, if you ever go to a Cracker Barrel Restaurant with Jimmy Dorazio (Yakus Appetiticus) do NOT get between him and a strawberry sundae. You'll be severely injured in the stampede - (whether or not the sundae is asymmetrical and has a vee bottom)

 

[oldyaker]

And..... If'n ya sleep in the same tent with Cat Five Jackus Blowholeicus..... Tie yer sleeping bag down with hurricane anchors! Wondering what direction the wind comes from ? BOTH! :shock:

 

[Kayak Jack]

And..... If'n ya sleep in the same tent with Cat Five Jackus Blowholeicus..... Tie yer sleeping bag down with hurricane anchors! Wondering what direction the wind comes from ? BOTH! :shock:

That's mean, Jimmy; that's cold. Santa will remember that in a few months - you just wait and see. Coal and straw for you.

 

[beekeeper]

Looking like a boat:

beekeeper