joachim
I don’t use the angel hair for structural… its a sacrificial layer for sanding/finishing purposes. It gives me a little bit of room to sand and finish with out hitting the good stuff…
I agree that the carbon and kevlar is HUGE overkill… but you can’t argue with the way it looks…
it is now fully off topics - sorry
Marc,
Why you are using glass in a sacrificial layer? It is enough to coat the laminate (before fully cured) with another epoxy layer, thickened with about 1-2% of thixo. Grind with mesh 400 or 600 paper. If the surface is still not smooth enough, repeat the whole process till you are satisfied. If you are grinding the glass away it makes no difference at all. The angel hair not at all a “protection” for the kevlar …
joachim
since I’m using a male plug. I don’t have the benefit of a nice smooth mold. Also, I’m not vaccum bagging. the closest I can come is using a heat activated shrink wrap. on the outside.
So, no matter what I have done I have always needed to sand. obviously if I intend to paint its much easier as then I can apply sacrificial layers of primer, sand, repeat.
if I want a a clear coat type finish, its much easier I think to have to only sand the hull to get desired finish and not have to keep adding layers of epoxy to prevent sanding through the structural layer of the hull.
fiber glass and kevlar and carbon, have a pretty aggressive weave pattern. since the weave pattern on the angel is so fine it seems to act as a primer to fill in the gaps of the larger weave
It works for me…I’d love to pop a hull out of a male plug and not have to do any sanding or finishing, but since I;m not bagging it I have to do the extra finishing…
Claudio
did you ever have a swing rig design for the esterel E…
I’ve been having some good results with the conventional rig, Won another regatta with it, but I’d like to experiment with a swing rig. I feel like I’m loosing some down wind performance. The boat points better than anything out there with the conventional rig, so I’d be willing to give up a bit of pointing for the added down wind performance of a swing rig or a una-rig…
Hi Marc,
here 3 configurations, one with a jib at 35%* of total area and the other with a smaller jib and larger main to get more power then pointing !
You may also try to move forward the jib boom anchoring point as such that once running a larger surface will be exposed to the wind under “butterfly” setting conditions.
Cherrs
ClaudioD
Thanks Claudio…
nice thing is that putting a tube in the deck to hold the rig isn’t a huge weight penalty
Key is getting the tube in the proper place.
the only problem I could see with moving the jib forward on the conventional rig would be opening up the slot too much…
going down wind is where I see the swing rig boats really making big gains on me. I can make them up going upwind, but it doesn’t leave any room for mistakes…
Marc:
I have used Frank Russel’s A-swing rig on my boat, positioning the mast tube center something like 3.5cm forward of the leading edge of the keel, with excellent results.
Claudio:
I did not follow your plans for keel/mast position. I just placed the keel where I thought it was better (a little aft of your plans, I think), and then tested various mast positions before settling on the 3.5cm distance. When I have some time this weekend I will do some measurements…
Yes, downwind sailing is a little better with swing-rigs, but upwind is better with sloop-rigs. At least that is the theory. In practice, someone here said to me the other day “races are won running downwind”, because there is not much you can do tactically to win when running; your boat has to do the work for you. When tacking upwind, you get the chance to influence results with good tactics… but running down on a straight line is up to the boats’s speed. I think this makes sense, so I favor swing over sloop.
For me, another BIG advantage of swing over sloop, is the weight savings. For sloop you need hull reinforcements at 5 points: mast base, forestay, backstay and two shrouders. For swing you need only for mast tube. This means a MUCH lighter hull overall. For comparison, my fully rigged hull (w/electronics & battery, wo/keel & rudder) weights less than 250gr. A Goth65 in similar conditions weights more than double!!
Hope this makes any sense to you…
Tarm,
yeah each rig has its plusses and minuses
I have found that going down wind has some tactical decisions and especially the last down wind leg. covering the person in front, staying on starboard and inside boat so you can control the mark rounding. for the final windward sprint to the finish…
I’ve never been able to build a “light” hull… my mast base support rests on the keel trunk so no real extra weight there with the carbon fiber deck I don’t have any extra reinforcement behind the deck points… but every little bit adds up…, rigging, turn buckles, ect
Hi Tarmstro,
here in attachment a schematic drawing describing my method to position the fin along the rocker.
In principle I use the major thickness point of the fin chord that is function of the profile chosen.
In my drawing I manage to position the fin as such that the LCB vertical line passes at 35% of the Fin chord. The same vertical line is joining the Bulb CG if the boat construction is well balanced. Not excluded that for centering reasons the bulb can be position a little backward in order to ensure that the LWL is keep horizontal during sailing !
This balance may induce ‘in static conditions’ to have the stern a little down. this condition will be compensated when the boat start sailing away.
The other vertical line is the one that shall reach the Sail Plan CE.
Nominally this vertical line shall be positioned in the first quarter of the Fin chord. Not excluded some variations around as the “tuning” will suggest.
Every sail plan has different characteristics ! Difficult to find two plans with the same.
From the CE is then possible to define the Mast step position and here again in accordance with the rig and sail shapes and during “tuning”.
For what concern the Running, it is important not to sail at 180° from wind but rather at an angle that will produce higher speed in spite of longer line.
This angle could be rather wide up to 25/30° !!!
Cheers
ClaudioD
Marc -
congrats on your recent win at Richmond. Sounds like you are getting Claudio’s design “dialed in” and now may only require minor adjustments (type of mast issue not included). I just pulled the deck off my own RG (2nd. time) and still haven’t settled on which type to use. One time the standard rig goes awesome, the next time the swing rig seems to be perfect. I may just add the second mast tube, close my eyes and grab a rig from back seat and simply race what I grabbed.
Besides - using this method of mast choice gives me additional excuses of why I didn’t sail well! :rolleyes:
Dick
I am considering cutting the foredeck off and making a peaked foredeck to help shed the water when the goes bow down in a puff, that way the boat, will track straight, even though it wants to be a submarine, easy enough to make a form out of cardboard and do a quick layup… but part of me doesn’t want to “screw up a good thing”
I’m considering the swing rig…easy enough to drill a hole and drop a couple tubes. Building the rig is the hardest part. Just gives me more options, especially when the air is light… the barn door nature of a swing rig going down wind is hard to beat…
Claudio. Yes I know going dead down wind is not the fastest VMG is often best done off wind quite a bit but sometimes you need to sail dead down wind as thats where the wind is…
Hi Marc,
happy for your winning !
Dead down is always a bad choice…
You remember america cup races ?
Dead down is also source for nose down !
You may also use a shorter mast while using the same surfaces
Cheers
Allright: there is the position of things in my Esterel65:
[ul]
[li]the keel slot is 335mm to 395mm from the bow (60mm in length)[/li][li]The center of mast tube for swing-rig is 292mm from the bow[/li][/ul]
So I was wrong: the distance from mast center to the front of the keel is 43mm! Now I understand why some people here were saying it was too much. But it works perfect in combination with the “A” swing-rig from Frank Russel.
Claudio: I did not measure anything to get these positions. I put the keel where I thought it was right, and then tested different mast positions until the boat felt right.
Tarmstro, a bit too short as statement, could you tell more about ?
This is my thought : the Fin shall satisfy two conditions :
A) be a counter action to the sail plan in order to create the forward movement.
B) be the support for the bulb
It may sound strange but the point B) is my leading parameter, mechanically speaking, unless I like getting in troubles!
Particularly with narrow Fin thickness, I choose the fin bottom wider point to insert the “bulb rod” and this is why generally this rod stay at 35% +/- 2% from the leading edge of the Fin. (see profile)
This is also why the Fin is centred at about the same position with respect to the LCB. In theory the LCB and CG (bulb) are on the same vertical position and the Fin is the linking object !
One can play with Fin ‘during Tuning’ for few mm only, therefore the most variable parameter is the mast step or the CE position of the sail plan.
Some times it happen that modellers are in troubles when the mast step is fixed in the wrong position and rarely they think that it is easier to modify the sail plan playing on the Main and Jib surfaces.
ClaudioD
You are right… that was vague from my part… lets see, your A & B items are the basic stuff… but I also thought of these:
C) Lateral resistance of hull+keel+rudder must counteract lateral force of CE (so that boat sails in straight line)
D) The more at the back your overall weight is, the less nose-diving you get when running.
I am no boat designer, I have no idea on how to put math into it, so based on D) I decided to move everything just a little back (no scientific method at all)… and based on C) I had to test different mast positions until happy. For me B) is a must (obviously) and A) is function of keel height and keel chord (in my case: keel is 400mm height, and chord is 60mm at the hull and 40mm at the bulb).
All in all, I just did everything using common sense and some good eye for things. And it worked! Ha.
Nose down is occurring most of the time unless the skipper is able to anticipate the occurrence by reducing the sail lift.
Point C is intrinsic with point B !
Point D is a long discussed argument, but …
A special hull is needed like the one used in the Van de Globe or VOR type (see sketch) where the water plan is producing a large displacement at the rear in order to sustain the weight. Here the mast is at 52% of the LWL.
This type of boat is a good performer except for Close Hauled sailing.
If that volume is not present, the boat will not perform hydrodynamically and will produce drag and loose speed.
Lowering the CE is probably the most efficient method other then thumbs training!
ClaudioD
mark you could possibly use a wave splitter on the bow its noting more then 2 carbon fiber tubes glued to the front of the boat and in big wind
you telescope the on tube out and it help sheds water off the foredeck. I use one on my venom us 1m and in 20 knots of wind with my c rig on it worked very
well. congratz on the Richmond classic win.
Mike
ktm…not sure I’m following got a pic?
The maximum tollerated by the RG65 Rules is 650mm. A “telescopic” device !!! vertical or longitudinal ? Extra servo needed ?
ClaudioD
Clearly not allowed under RG65 rules. Boat has maximum overall lenght, and only 2 control channels allowed.