Blue Sky Skiff v2

Well … here she is …

400 g displacements
340 mm loa
128 mm beam

Still worried she doesn’t have enough volume up front … transom SHOULD stay out of the water … our composites guru, Mr Heron will bang out some copies as soon as I can get the plug over to him … foil against foil and rig against rig testing will commence sometime in spring …

blue-sky-skiff-002.jpg blue-sky-skiff-009.jpg blue-sky-skiff-030.jpg

Brett, I’d love to include your unirigs in the testing …
If there is anybody building foils they’d like to share, let me know …
Likewise, if there is anybody building 250 g bulbs they’d like to find a home for I’d love to hear from you …


PS … I’d love for Blue Sky to make the April Internet races but given my current workload there is no way I’m going to make it happen … therefore I’ll send a free Heron built hull to anyone who wishes to get a Blue Sky on the water for the event … (ummm … maybe I should limit the number … in any event … if there is a taker, let me know)

Isn’t it a little long (at 340mm) to be a Footy?

Shouldn’t be … this referenced from Intentions document …

B.1 The important intent was that a boat should be measured in racing trim, so that a 12" wide boat with its rig up and set for every course would not be able to fit sideways within the box. The intention was to permit a boat to be fitted with its axes at an angle to the box axes. Otherwise a tank measurement or some other complicated method would have be required to establish the waterline axis normally required by the ERS.

Thanks again to the tech committee for posting the clarifications and intentions piece … :slight_smile:


What do you think, for future postings like yours, about including a picture of the boat in the box, so others can see how it was measured?


No problem, here’s she is in the box and with her intended rig … the main is cut high to clear the sides of the box … it (the rig) travels 360 degrees without contact … what starts in the box stays in the box



You are too sneaky :graduate: :devil3:

i like it!!!:stuck_out_tongue:

Hi Trevor,
I don’t think you would be able to get the boat to mearsure with my rig.

Plug and design looks great,the whole execution of this design will revolve around the rig though.
Interesting concept and I wish you well with it.
I to have built a plug for a diagonal boat.I havn’t gone so transom down though.
I went corner to corner across the top with slight transom down.
Result is about 330mm long and 90mm beam.Your approach allows for greater beam but compromised rig.
My design has no comproimises with the rig,but limits beam.

I am not totaly sold on this design approach though as a 305mm hull with 51mm overhanging rudder is still longer and has the rudder quite a bit further aft than these diagonal designs.(quite a bit of displacment in a 6mm thick overhanging rudder if you want it)

Brett … in plan shape she reminds me a touch of the international canoes … there are none here that I know of, but if I’m not mistaken, there are a few on your side of the equator … there is also (now I’m stretching) a bit of international moth in her … what displacement is she?

Interesting comments about the rudder … blue sky is in fact intended to hang a rudder off the transom … given her angle there is in fact plenty of room to extend a rudder past 50 mm and still keep it in the box …

Blue Sky’s rig is sorted … i will try and show pics with it assembled and rotating … it may be worth noting that as shown above she is only loosely propped in the box and that the angle is steeper than what will actually be required … the box in that pic is also 10 mm narrow than what it should be due to my own lack of attention when gluing it together … add that to the fact that the rudder nib on the transom will fit through the slot flattens her out substantially.

As for your rig … you’re right, I don’t think the foot would be high enough … and would require some alteration … I am eagerly awaiting your drawings / pics however because I DO believe your uni-rig is an elegant simple approach … and I WILL want to cross-test an altered uni-rig against a blue-sky rig as pictured above …


ps … how may copies of your diagonal hull are you thinking of producing for testing ?

Hey Trevor - I’d be interested in a breakdown of the weights of the various r/c components, rigging, boat and ballast, that you plan to use to bring your good looking hull in at 400 gms. I’m sure we could all use your insights to trim down our boats! 14 ounces is very impressive.
Also, how will your rudder linkage fit with your diagonal placement?

Starting with what I can’t change …
[li]60 gms … 4 Lithium AA’s
[/li][li]15 gms … 1 Micro Servo for rudder
[/li][li]20 gms … 1 Adapted CD motor for sail winch
[/li][li]10 gms … 1 Micro Receiver
[/li][li]5 gms … Antennae, wiring harness, switch etc
Add targetted weights
[li]40 gms hull and appendages
[/li][li]20 gms rig
[ul]230 gms … lead bulb
It seems light I know, but guys like Nigel and Angus have both referred to components and weights within the range. Brett just a couple of days ago sugggest a uni-rig target of 10 gms. Nigel in a previous correspondence suggested a target hull weight substantially below what I’m suggesting. Electronics can be sourced lighter but would require greater engineering to function reliably (leverages or reducing gears to actually make them strong enough). Honestly, I don’t think it will be that hard to achieve …
… believe it or not they are actually flying a fully functional 7 gm infrared controlled helicopter!

My goal is to use 250 gm ballast which means having to trim even more grams.

As for the rudder … the idea is to run an internal tiller attached via an articulating linkage directly to the servo … I’ll post a pic in a few days when I can grab the time to actually draw it …

Regards, Trevor

what and where to get them lithium aa’s?

Can you post a diagram of the electronic controller for the CD motor?


Camera stores … maybe Radio Shack (The Source) … ebay

Yup and nope … the trick is not the controller but the reducing gears … the motor rotates at over 500 rpm which provides a huge punch when geared down by a ratio of 10 or more — sourcing light enough gears is the toughest part … try hacking an old dvd player or walkman

in any event next weekend i’ll take pics and post a wiring diagram


i just ripped apart a cd player today. looking for a micro switch.
i took the motor out too. if any body wants it, let me know, and i’'l mail it out.

4 x AA lithium cells is almost 15 Volts. Maybe you mean 2 x AAs? You can get then in 2400 mah size:

I like to gut & disassemble computers, hard drives, floppies, vcrs, about anything. There are some great motors, connetors, & gears there.


I found Energizer Lithium E2 at Radioshack for $22. 1.5V cells

I looked into those E2 cells. they weren’t very impresive, because they’re throwaways, so I just got some more NiMH cells. $22 can get you 22 regular alkaline cells.

question is, are the weight savings enough to spring for a 22 dollar set of nonrechargeable batts?