ThistleDew's AB23

[peter-curacao]

Thistle,

Sorry I missed this post earlier must be my vacation intoxication , but I'm also glad you're doing okay now, hope you didn't lost your sense of humor with that pneumonia, I'm also exited you are starting on that AB 23 can't wait to see her come together.

[ThistleDewDayDreamin]

Hey gang!

Well this is turning out to be a very serious bit of wisdom.

Looking forward also to the scale model idea, it is a time tested tactic from the old days to build half models to get a feel for boat construction of a new design, so you are walking down a well trod path.

I am missing something in the stack up of dimensions using the optional bracket for the outboard. ( more on that later ) but as I was cutting molds and stringers I realized the complex geometry of these hulls when you go from 2D plans to a 3D build-up. Working with balsa HAS to be different from full scale full size sheets of marine plywood. The strength or lack thereof of the stations and the bow mold make it impossible to use them as you really do when building full size. The balsa for the hull panels won't bend to conform to the molds without cracking and splitting with the grain. I'm fiddling with moistening the balsa and setting it in a "jig" made of household items to try to get it close enough to the mold shape to be able to glue it all up.

I'll post pictures when I get that figured out. But for now, suffice it to say I'm glad I had this chance ( whatever the circumstances ) to work with the design on a scaled down size. I'm certain it's gonna save me time and $$ when I start the real build.

The "Some Day, Wait and See!" deck layout is as shown here, but maybe with the console extended a bit forward for some sort of head.



The model looks like this so far today.



Notice the wide gap between the motor well bulkhead and the next frame forward. This is how the plans show the layout using a bracket for the motor and a full transom. That wide span is a question mark in my mind. for now I'm going strictly by the plans, but I may want to go back and ad a frame forward of the motor well bulkhead later. On a full sized boat, that long span is right where people will be moving around and jumping up and down with a fish on.



While holding the side hull pannel in my hands and warping it to conform to the shape of the molds it became very obvious how important and how tough that bow mold needs to be to achieve that twist and bend around the molds forward of station "C" to the bow mold. You would never be able to "feel" with your hands the torque that panel needs to take to conform to the molds. Working with the model gave me an insight there I wouldn't have had otherwise. I won't be skimping on the bow mold or the "A" station reinforcements of the the strongback when I get to the real build, that is for certain.

[Bowmovement]

Looks cool TD,
I want to do that myself. Was planning on building a model of the OD18 and then didnt. Not sure why. Now would be a good time to do that seeing as I dont have the time, space or money to build a big boat.

Matt

[topwater]

What are you useing for your frames and stingers? From the pictures it looks like all balsa.
They do have lite modeling ply in different thickness that would work great for frames and stringers
and would stiffen up the jig quite abit. Would also be much stronger when you cut out your finnished
frames after roll over How did you make those nice scale patterns for cutting

[Spokaloo]

By scale, your sheathing wood needs to be like 1/32 or less. Remember with 1/16" balsa you are making what in full size would be 1" thick ply or better, which isn't the case.

See what the thinnest stock they have available is.

Secondly, you might be able (checking with Jacques) to cut down the top of that frame and scoot it back to make the dance floor bigger aft. Also consider a bait tank if it needs to be there, as that would be a sweet spot for a live bait tank, a few tuna tubes, and some tackle stations.

E

[ksm330]

I used door skin to make a model of the FS14. I took the inches on the plan, multiplied by 4 then divided by 10 then used that number in centimeters to get my scale (i.e. 24" becomes 9.6 centimeters). It came out to be the right scale to get the door skin to make the bends. I ended up with a model that is roughly 24" or so in length so yours on the same scale would be roughly 110 centimeters or roughly 4'. You will have much more complex curves in your model, but maybe a few strategically placed scores with a razor knife will help with the bends. When the panels are installed, you can cover up the slits with a putty or thickened epoxy. I have made many models of sport-fishers & Yachts to show customers how we can change deck configurations and cabin layout when refitting / remodeling. Door skin is definitely my wood of choice for the modeling. Especially the hull planks.

Hope this helps...

[ThistleDewDayDreamin]

What are you useing for your frames and stingers? From the pictures it looks like all balsa.

I did use 1/16 balsa for the stringers and the frames / station molds. The thinnest basswood ply was way too thick for my scale.

How did you make those nice scale patterns for cutting

A little no frills illustrater package called "Canvas" It's by a company named Deniba (sp?) out of south FL, I've had it for years. It's not a true cad package, it's really just a drafting aid.

By scale, your sheathing wood needs to be like 1/32 or less. Remember with 1/16" balsa you are making what in full size would be 1" thick ply or better, which isn't the case.
See what the thinnest stock they have available is.

This is where my problems with the shaping the balsa hull panels started. I did use 1/16 balsa for the frames and stringers. Tried to use the same to bend the side hull panel. It's just to thick to form without steam or hot water, and you can imagine what that does to thin balsa, 10 seconds too long and you are working with wet newspaper!

You're right about the scaling. My 23+ foot AB 23 is coming out as scaled to about 24 inches over all ( without the engine bracket ) The scale IS somewhat arbitrary. I do not have a plotter at home so all my patterns have to be printed on regular letter sized paper. That was part of my selection for scale. The other part was the available balsa stock. It tends to be 1/16" x 4" x 36" stock sheets as sold at the local hobby stores. So I wanted to use a scale that would allow me to get the bigger hull shapes out of one sheet of balsa. Yes it's intended to be to a scale, but I'm not OCD enough to "make" scale 4x8 sheets of plywood to build from true scale components from the keel up. The scale came out to be something on the order of 2.800" = 32.000". Odd? yes. Convenient for the printer and balsa stock? Yes. -- I'm gonna try a piece of 3/32 for a hull panel, spacifically the hull side panel. The chine, and bottom could be made from 1/16. There isn't the torquing on those sections, but that side hull panel won't work with the 1/16.

Secondly, you might be able (checking with Jacques) to cut down the top of that frame and scoot it back to make the dance floor bigger aft. Also consider a bait tank if it needs to be there, as that would be a sweet spot for a live bait tank, a few tuna tubes, and some tackle stations.

Yes. The motor well bulkhead ( formerly station G ) has already been moved back some 13+ inches. It leaves about 11 1/2 inches behind that bulk head to the transom. That's also where the big span I noted earlier comes from. It could end up acting more like a trampoline than a dance floor with that much span, I intend to ask Jacques about it sooner or later, at this point, it isn't holding up a real build so I'm not gonna bug him with it.

I'm torn between a big bait well - rigging station right behind the leaning post ( that's sort of shown in the cartoon deck layout above) with rocket launchers over head on the back of the top, or moving that motor well bulk head back forward and putting the live well in the transom. I kinda like the idea of having the room back there for batteries, wet storage and other out of sight "stuff". 50 gal bait well full of water might be better located more forward for balance. This is all just academic at this point, but it is a good way to play "what if".

I used door skin to make a model of the FS14. I took the inches on the plan, multiplied by 4 then divided by 10 then used that number in centimeters to get my scale (i.e. 24" becomes 9.6 centimeters). It came out to be the right scale to get the door skin to make the bends. I ended up with a model that is roughly 24" or so in length so yours on the same scale would be roughly 110 centimeters or roughly 4'

I'm not sure at all that I know what you are refuring to when you say "door skin", could you elaborate?

[bwd3]

When I try to bend thin balsa into hull shapes, it very often splits.
Have used posterboard and cardboard with ok results, and really thin -1/32 to 1/16- plywood.
The plywood works and looks good, but costs more.
Order it from a airplane/model airplane house (for example, aircraft sprcue) if you want to try it.
AB23 looks cool, enjoy!
And take it easy in your recovery, sometimes people find they get their "strength" back in a month or so
but stamina/resilience tends to take longer.....

[tech_support]

we made an FS17 model and for the hull panels we used very thing fiberglass. We laid a few layers of 6 oz cloth on waxed surfaces, then wet them out with pigmented (white epoxy). We cut the panels out with a razor knife.

I have to admit though, Im not a fan of models in general. Unless its purpose is to demonstrate how the boat goes together (helpful to someone who cant see it on a computer screen). We took the model with us to some boat shows so we could quickly give people the idea of how the panels bend to make a hull shape. One can readily see real boats going together on the forum

[Spokaloo]

Don't discount cereal box cardboard, it is the right thickness, has similar properties, and the price is right!

E