Just a thought, but when looking at NZL-20-6.pdf, I noticed that the position of the sail winch is offset to starboard and assume that the battery will be to port to counteract the weight. Would the weight distribution be better if the winch were rotated 90 degrees (when looking from above) and mounted centrally and then the battery either aft of winch, forward of mast/fin bridge or below the winch? I’m just thinking that with such a light displacement (as with all AC120’s) that keeping the weight as near to the centre line as possible and also as near to the designed vertical CoG line as possible might give improved handling characteristics. Also, for the sake of a few grams, could the rudder servo be brought further forward and then use longer connectors - thus keeping all ‘heavy’ ancillary equipment as near to vertical CoG as possible?
There may be good reason for your designed layout - I’m just interested to know if other layouts might work…
Further the bulb is just there to compensate the mass centering since his efficiency in term of mass is much higher !
Cheers
ClaudioD
PS:
For better understanding this drawing show my method to reach the masses equilibrium and avoidance of traveler sheet interferences. Of course any one can make his own choice and will be interesting to see other options !
Well done Claudio !!! I should be finished this evening and will post update tomorrow.
Unlike yourself using below deck sheeting circuit etc, I will be using above deck continous loop system for sheeting attachments, rudder horn & keel lock as I find more convinent from my experience, further I shall be running step-less jib pivot with Jib traveller bar.
I will also move the fore deck further back into the cockpit.
Claudio, can you share with us, why you have designed 15 mm keel & bulb adjustment, when you have never done this in other IACC 120 plans before ?
Hi Alan,
Your idea ’ above deck’ for the rudder may I copy it since it is easier to unscreew the rudder stok without the need to remove the self adesive cover. Some grease into the tubes may help to avoid water leakage inside. Thermo shrink tubes may added too. The winch and sheeting will remain “all inside” since I’m more familiar with my fairleads as described in the 43-900 or Azur treads.
About the shifting possibility of the Fin is coming from some thinking about the "idea"l position of the “couple RIG-FIN” along the Water Line.
Basically my view consist on recessing as much as reasonable the “couple” toward the stern in order to increase the distance from the bow and trying to fight against “'nose down”. Some one already tried on IOM class were it was mentioned having found some problems due to expected turbulence from fin to rudder. The true story in not clear yet.
This idea is not new since aleady introduced in the AC100-B project . Unfortunately I did’nt got time yet to test need in the water with various winds !
Actually the basic solution is with the fin trailing edge at 517mm from stern.
I’ve copied more ideas from you than you could ever copy from me Claudio albeit it’s not my idea, alot IACC 120 boats use the above deck rudder horn for the same reasons you wish too.
Planking job is finished ! party time for the boys :party:
On the weekend I shall fill gaps between planks with mud (filler to stop epoxy leaking through the balsa) on outside of the mould then coat inside with epoxy and then be ready to sanding for final finish.
Cheers Alan :zbeer:
P.S Just seen your redraw of my above deck sheeting…thanks !
Claudio, just after having second look at your redraw of the sheeting, I would highly recommend anyone wanting to have little extra rig tuning should use keel stepped mast with mast ram, controling the bottom 1/3rd of the mast bend with the ram makes quite a bit of difference.
You don’t see an IOM without one & they have shorter masts :rolleyes:
Further assembling the boat lake-side is lot easier when you just drop the the mast in it’s box and it stays upright, then you not trying to attach the stays and shrouds while holding the mast on the deck.
[QUOTE=Don;62454][QUOTE=K1W120;62450] I shall be running step-less jib pivot with Jib traveller bar.
Hi Guys, Is there a little more info on this somewhere? Thanks Don
Hi Don, The jib bar (in my opinion) is huge benefit in close hauled & close reach position as it holds the Jib boom in position and stops it from lifting in particularly in strong gusts, which causes loss of Jib tension & critical twist.
When sheeted out to mid to full reaching position the Jib moves the same as normal.
I always found with stepped pivot anchor on the deck I could never put my Jib where I wanted it, so I started thought up the idea to have a Step-less Jib slider that allows to move the pivot point to any position over 100 mm on the deck, have been playing around to having pivot down as low as 10% of the boom chord and works well.
Congratulations on the fully planked hulls - am watching the progress with a not insignificant amount of envy…
Alan, in your post where you refer to ‘mud’ for filling the planking gaps, is that another type of filler you’re using? It’s a term that I’ve come across on a lot of US posts/threads before & known it to be filler but what sort?
Why should we consider using a Servo-arm insted of a drum? What are the benefits vs the drawbacks of each approach? Speed? Precision? Price? Simplicity of realisation?
Hi Sylvain,
the servos used with the arm are more numerous on the market then the ones with a drum and several turns.
From power point of view the servo drum are generally limited to 12/14kgcm , while the other servos can go up 28kgcm and more, unless the expensive RMG servo drum is choosen.
From speed point of view the servo to be used with an Arm are much faster compared to the drum type.
The installation requires some precautions for the positioning inside the hull due to lenght of the arm than need to turn about 120° /140°. Most of the time the Arm can turn horizzontally, in the above diagramme is turning vertically because of the Cockpit recession below Deck.
Cheers
ClaudioD
PS : Typical settings of a servo arm when space available. In order to keep a centralized mass distribution, in this particular case, the Arm is turning above the Fin Box . Access to the retaining nut requires removal of the self adhesive protection:
Hi Row, I think the terminology “mud” is American slang for filler, in my case I use light weight modelling filler which has higher viscosity than the normal auto filler, with the consistency of runny peanut butter…if that makes sense, easier for those small gaps between planks.
Claudio, I had not thought about servo arm set-up but given the room inside this hull design it is a great candidate for servo arm instead of drum winch used traditionally in narrower hulls designs…should be lot less expensive too !
The support should like a box similar to the Fin box. The top will receive a perforated brass plate to position the Mast pin. Water entrance limited by a diaphragm fixed about 7mm below.
albeit it’s not my idea, alot IACC 120 boats use the above deck rudder horn for the same reasons you wish too.
