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[Glyn Roberts]

I am going to build the huntsman that DM is featuring in model boat mag. and I thought I might as well also build one 200% of the 590mm boat.
Doubling the size brings up some queries, such as do I double the thickness of the ply from 3mm to 6mm and are the chine stringers doubled up in size.
By up scaling the plans to 1/8 means that the cutouts on former's will be doubled as well.

Do anyone have any thoughts about this, I would love to hear from you.

Regards Glyn

[Arrow5]

Not "liteply" , go for birch from an aeromodelling supplier.   Sizes from the more experienced, but my guess is 150% at most,  never 200%

[dreadnought72]

I wouldn't bother doubling the skin thickness.


The original boats were made of laminated mahogany. 6x2.5mm in the Huntress, 'more' (8? 10? I'm not sure) in the somewhat larger Huntsman. At its thickest, that's under an inch.


My dinghy (13'6", and people standing in it) used 9mm and 6mm marine ply. There's no way, in your model, you structurally need 6mm ply if the ply is well-bonded to stringers and if you don't aim on driving it into concrete objects.


Stringers? On a four-foot boat? 6mm would be plenty. 4mm would work. If the shape's sweet then it's the monocoque hull that's taking the load/doing the work.


(We vastly over-engineer model hulls. You, however, want a light, fast, planing hull.)


Andy

[canabus]

Hi
I am building a Sea Raven, which is a mix of a Sea Commander, Rover, Huntsman, Huntress, Swordsman.
It's 37 and1/2 inches(950mm), I used 10 square each side of the heel, 4mm stringers on the bottom and 3 x 6mm(doubled) on the sides(bottom and deck corners).
Frames 3mm marine plywood and skinned with 1.5mm marine plywood.
Floor stringers I used 6mm.
I am coating the inside with fibreglass resin.
Motor is a 1900kv brushless with a 60A ESC and a 3S 5800mah battery.
You will need to steam the stringers and plywood at the bow end.
I use an electric kettle with the auto cut of disabled.
If you set up a board with a bit curve in the pieces you are steaming, when dry the extra curve is easier to clamp onto the hull.
The strength of the hull with the stringers will be strong as an OX, but, not over heavy.

[inertia]

Below are some diagrams from the original Modav 47" Huntsman manual (hand-drawn in 1972!). All of the ply parts were marine-grade birch plywood. Decks and interior side parts 1/8"; keel 3 x 1/4"; sides, transom and bottom skins 1/16". I would now increase the size of the chine stringers to 2 x 3/16" x 3/8" and use balsa blocks between the chine stringers and deck forward of frame #8 (which is frame #2 on the smaller model plans) to get the correct compound curve to the sides. For a model of this size liteply has limited use because it's not as strong as marine ply. I use SLEC as suppliers for all of my wood these days.
DM

[Glyn Roberts]

Thanks to all who shared their thoughts on the subject, therein lies food for thought.   Thanks to inertia for the drawings and  also for making it possible for old reprobates like me build the huntsman in the first place.  I use SLEC for all my timber needs and am lucky in that they are only 20 miles from my house.
I will have to redraw the cutouts for the chine stringer to fit the timber used.

Regards Glyn

[FsASTSyd1]

Might be worth your while to see if you can contact the King Lear MBC for at the 2014 IMBS they had both a Huntsman and a Swordsman at 1/5 scale

[Glyn Roberts]

thanks for that lead FsASTSyd1

Regards Glyn