Bearospace Sloop EMMA - Page 6 - RC Groups
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Jan 31, 2018, 08:43 AM
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Looking forward to seeing your video on your Emma winch system. Are there two types of winch servo pulleys, one that transfers the line from one groove to the next groove on the pulley and one that is more or less a continuous line that wraps around a single groove on the pulley? When using a sail arm, if you run the line threw a pulley on the sail arm and tie off one end to somewhere near where the other end of the line goes threw the deck and connects to the sail, does that double the line pull distance for the servo? I've seen where some people do use a pulley on the sail arm.
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Feb 01, 2018, 04:14 PM
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I found a couple of good web sites that explain some of the pro's and con's of sail arms vs winch setups. I believe that what I was referring to with the pulley on the sail arm is a "double purchase" setup that will almost double the amount of line pull length . Good websites https://www.theamya.org/hints/sailservo.php http://ec12.org/disc/viewtopic.php?f=2&t=1528
Feb 02, 2018, 01:41 AM
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robcrusoe's Avatar
Stephen

Your sites are good, explains a lot.

However you don't get twice the sheet travel for free. The effective power of the winch is reduced by 50%, but only noticeably under load.

In light airs it will look great, but when pushing hard through mounting seas and strengthening wind, very slow boom movement.

When my Maxine is fully operational I'll do a video of the two boats operating their respective winches. Bit hard to do on the water but on a stand I'll use weights to show what I'm on about.

In the standard Emma the arm winch is located centrally which is normal. But if you want a really long arm that will move unimpeded as much as possible, you could mount the arm servo right over to one side with the arm going almost to the other side. with the battery on the other side lateral balance should be reasonable.

But I wouldn't recommend anyone spending too much time on winch design, the standard Emma setup works really well as it is.

One of the main reasons for making a second Emma is to be able to test what happens with fully available boom travel. Up to now the standard rig seems to be achieving most of what is needed.
Have a look at this test sailing video I made yesterday in stronger conditions, in particular constant wavelets and occasional strong gusts.

The video is just edited to the better bits, not intended as a spiffy production. It also show show much water c an come over the bow.

Anna crusoe 2 (4 min 2 sec)
Last edited by robcrusoe; Feb 02, 2018 at 01:49 AM.
Feb 02, 2018, 02:48 PM
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another double ender


Looks half Emma, half Irene
Feb 02, 2018, 03:58 PM
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Zbip57's Avatar
Quote:
Originally Posted by g'n's
Looks half Emma, half Irene
This one even more.

Pinky Schooner (4 min 24 sec)
Feb 14, 2018, 02:16 AM
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robcrusoe's Avatar

Does an Emma ever get water over, or in her?


If you sail in weather like we had today. Yes, and yes.

To give you some idea of how and why..

Anna in the wet stuff (3 min 28 sec)
Feb 14, 2018, 02:23 AM
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robcrusoe's Avatar

And did the others see her


Not many got up close, that's for sure.

Rc sloop Anna with the hammer down (4 min 43 sec)


Wind was generally 20 - 30 knots with a few even harder gusts.. Other boats found it either impossible to sail or, difficult.

Overall she took on about one cup of water in 3 hours sailing. How? I don't really know but it was to be expected not a problem so long as it gets dried right out afterwards. You can see how the deck cops a lot. The waves very pretty big for our lake. See if you can spot her "planing".

Will she take even heavier conditions.? . Possibly.
Feb 14, 2018, 02:26 AM
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robcrusoe's Avatar

Study of an Emma moving through water.


I film is slow motion for this, it lets you see just how the two main elements interact with each other.

This is just a minute's duration of selected clips..

Anna SloMo (1 min 13 sec)
Feb 14, 2018, 07:02 AM
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Nice !! She took the waves very well for that kind of wind and waves. Do you have the deck on your Emma glued down or removable?
Feb 14, 2018, 02:52 PM
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robcrusoe's Avatar
All 3 decks are screwed down to 14 pine blocks around the perimeter. These must be stainless steel (or brass, if you can find any of a suitable size) but don't need to be very big.
I chose this method for my first boat, the Molly b, as I just couldn't bear the thought that as soon as the glue dried, and I test sailed it, I'd find I'd done something terribly wrong (happens) or more likely, eventual maintenance on waterproofing or the winch system. Truthfully, I can't see any of that becoming necessary, but it is just comforting to know the deck can come off.
But, no matter how close a fit ALL the way around you make the deck section (mine have improved with practice) it is very likely that in wet conditions, like yesterday, considerable water will get in. I must confess that in my boats I have thought the drain holes in the bulkheads unnecessary. Turns out they would indeed be helpful to have the water ingress collect at the lowest point, the bilge area? So, I employ a large plastic syringe with a length of plastic tuber attach and simply suck it up. Then the boat is left in the sunny breeze fort a few hours to be totally dried out. I intend to put those drain holes into the sloop Maxine as she is still under construction.
However, it is necessary to employ some sort of sealant in that seam between the deck and the hull. First, I lay masking tape along the deck edge and vertically on the hull surface where the two meets. then, using my fingers, squeeze acrylic based gap sealer in (take so very little and only needs a skin, really) then when it cures enough, wipe a damp rag Over it to smooth it flat (you find it slightly recessed, but that's OK0. then simply remove the masking tape which has kept the sealant off the paintwork.
Should you need to remove the decking it would only require a careful run around of a thin blade to enable you to carefully pry the deck off. That is also why you only want to use the minimum of sealant; gap filler is a surprisingly good adhesive if used in a heavy application. I know as I set up an experiment early on where I used two pieces of scrap ply, lain a thick bead of whatever compound I was testing for bulkhead fixing, left cure for a week and then tested each to destruction. The good stuff, like Sikaflex liquid nails tore the top ply away under destructive testing. But the gap filler also did an amazing job, if not quite so "attached".
Sorry for the lengthy reply, everything is relative, though.
Feb 26, 2018, 07:59 PM
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Alternative tiller


The tiller's D-shaped hole wasn't happening...I wanted a quicker,easier, and hopefully better way.
Ace Hardware provided a 1/4-inch locking collar. It's steel and comes with a tiny set screw that was replaced with a cap screw that takes a larger Allen wrench. Yes, steel, but I'm in fresh water country and the rudder assembly will be removed from the boat every day. Du-Bro makes 1/4-inch brass wheel collars but they're far over the mountains from here. The tiller assembly could be silver-soldered using brass parts.
The tiller was shaped from 6061-T6 aluminum about 3/32-inch thick. It was an R/C airplane landing gear. The collar was epoxied to the tiller.
It would have been much better to have glued the collar to the landing gear and then cut out the tiller. My tiller was slightly out-of-square to the rudder and was adjusted a bit while the glue was still soft.
The rudder shaft could have been filed much less, just a small flat for the collar's set screw. It could have been flatted only a short way on the length of the shaft, not all the way to its end.
This tiller locks onto the rudder shaft at a precise angle and with strength. A wing nut will be tightened over it for security.
This was quick and easy to do. The set screw will be shortened. Too bad I didn't finish caulking the hull before installing the rudder block
Feb 28, 2018, 03:06 AM
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Match Racing the two Aussie Emmas


Finally , Crossbones and I got together on a very windy late summer day to see how the two near identical boats would perform. Of course, we both know the individual skipper of the day also can be a vital factor.

Anyway, with a 10 -20 knot westerly (our best source of steadier wind) off we went. At first, he had the better of me (no surprise) but after some tweaking of the sheets and adjusting of the sprit I seemed to have reversed that.

Both of us of the mind that it would be handy to know we can remove the deck if ever the need arises, and as such we just screw it down into the deck support blocks. I had tried Anna like that but found that as she heeled water could get down into the hull, not a big concern but not desirable either. So, I worked acrylic gap sealer into the tiny crevice, just enough to form a water barrier. And my tests showed it works fine. But CB was a little unsure so thought to give it a “go” today, expecting maybe a cup full due to the conditions.

Well, have a look at this video of the race, as it was, and besides noting how well the boats performed manoeuvres in unison, whether his concern was over or under stated. I got about a cup full over an hour or so under sail,.
Rc Sloop Emma Match racing, first tryout (2 min 54 sec)

And Gary has already convinced me, for one, that the sprit is a top factor in setting the sails.
Today’s wind was around 15 -20 knots, but when the gusts arrived, and everything took off, it went over 25. At one stage neither boat could tack OR jibe and as that was only under the strongest gusts, you might well rate the Emma maxing out around 26 knots.
It would be awesome to have maybe 4 or 5 of these doing the same, the other group skippers can’t get over just how well these two race, and are envious to the extreme on how speedy and precise they tack.
While sailing any of these boats on one’s own is so enjoyable, sailing with, or against others, ramps that up a few notches.
The second video is 60 second of what it would be like to be have been hanging onto the tiller. You can see my trusty Mobius cam perched up high back there.
Rc Sloop romping in 15 - 25 knots. (1 min 1 sec)


I have a mod to stop water getting in around the mast, but no photo right now, it wasn’t on either of these two today, though.
Feb 28, 2018, 06:44 AM
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Very nice video. It is very interesting to see the view from your on-board camera. I am a little surprised that you got that much water in her since you did seal the deck to side seams. Do you think it is coming from the mast to deck joint or maybe a hatch? What material did you use for the sails? I really like the different colors for the main sail and jib. Also could you or Gary explain more about the sprit and how it should be set ............ should it be fairly loose or tight. Looking forward to my build.
Feb 28, 2018, 05:07 PM
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robcrusoe's Avatar
Thanks Stephen, good to get some feedback, let's you know it is worthwhile posting ,sometimes.

It definitely gets in via the mast/deck union, more so when under heavy going when everything is flexing and the decks are often awash.

I've had to rethink my attitude to water in the hull as I've just discovered that the ply that the deck cabin is made out of has started to de-laminate
I will have to open the hull after all and check everything out but I suspect that water VAPOUR, rather than just water, is the culprit. Water vapour is insidious stuff within a hull and will affect timbers and electronics in a way that you only find out when the problem is well entrenched.

As with any rc sailboat it is imperative that vapour gets removed sooner than later and in that respect I'm going to ventilate the hulls immediately after after sailing for the day. I'll do this with a PC cooling fan over an opened hatch, with the others also removed to allow free movement of the fresh air. Might seem a bit pedantic but it isn't. Gary will tell you, I'm sure, how even on a full sized sailboat that it is also a prime consideration.
As for the sails, they are just cotton poplin which is cheap and easy to sew up (with a machine, bit longer by hand ). Gary's instructions should be followed exactly although I have allowed 20mmk extra all round, rather than 12mm, as it makes it easier to fold over and sew. It also allows the seam to be flatter.
I'm currently making sails from light kite nylon ripstop and am yet to put that sloop on the water. I expect it to be no less effective than the cotton, but maybe even more so as it is wind proof and much lighter.

In the meantime I will check all boats out for any water damage.

Re the sail sprit. Yesterday was the first day I could actually see what happens, one way or the other, but rather than give my novice impression, leave it to Gary to explain. It is rather clever.
Feb 28, 2018, 06:16 PM
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Preventing water ingress via mast hole in deck


While I'm sure this idea could be bettered it seems an easy and highly effective way to keep water out.

The wooden block could be improved by making the block top slightly angled to allow water to be easily shed, maybe a flat narrow shoulder for the O ring to sit on. The O ring needs to be slightly under pressure to stay put. What water gets past this is of no consequence, and only then under heavy going.

The block need not be so large, but at least that high.

The central pin not only locks the mast fore and aft (should be done on Irene as well ) but allows the handler to use the mast ( with due care) as well as the hull, to lift the boat. This is only useful at venues like ours where launching is often a case of putting in or taking out the boat, and not yourself.


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