The volans hype just died, the joysway DF-Cat prototype gets some ‘ship shape’, so in between I though it is time to post something about my first RC-Sailboat.
I guess it’s one of the first multihull building kits you could purchase back in 1975. Luckily my father bought one for me and over the years I had periods with more or less sailing with this boat.
So you may call it a vintage catamaran and you won’t find wave piercing bows, foils or wings in this thread.
It’s and old fashioned catamaran, may be the oldest rc-cat and this thread is more about rig control.
lenght 96 cm (37.8 in)
beam 62 cm (24.4 in, one half multihull40)
The weight of the boat is about 2.2 kg. The hull is made of ABS.
The hulls handicap are these broad keels (1 inch? On the starboard I use these keels to place 5 eneloops AA R6 (2000 mAh) inside )
electrics:
5 eneloops AA R6 (2000 mAh)
main arm-winch servo hightec HS-815 BB; 1:1 ration, 180°
jib arm-winch servo new-power XL-37HB; 1:2 ratio, 100°
MPX-Mini HD rudderservo
A preseason shot with the c-rig:
closer look with b-rig
some tacking trainig with the a-rig
I build these rigs with four to six panels:
a-rig with 1.65 m mast height
b-rig with 1.50 m
c-rig with 1.35 m
A d-rig will follow soon.
mast: EXEL Extreme/Cruise 10 mm
boom: EXEL Extreme/Cruise 8 mm
It has a nice size for transportation:
Recent severe hobby-horsing in waves of hull size:
(I love this term I recently learned
In the mean time I use excessive rake at my cat rigs. I like a touch of weather helm and during a bear away everything is fine as long as the mast isn’t tilted forward. Maybe it’s a mental thing but I feel better when the thrust vectors are at least horizontally or pointing upwards.
An early vid with a single arm winch for both jib and main:
The rake is limited by the weight of the rig, when the stern gets wetted. So I modified the stern to get the stern easier free.
Maybe I could attach the jib closer to the waterline but with a flying windward hull the jib would get more disturbed air from the flying bow. This wouldn’t be nice because my jib should get full throttle all the time. Usually I reef down to a smaller rig too late so I use the main arm winch to depower the rig in a gust.
I tried different sail servos and made these experiences:
a:
drum winch with constant drum radius and endless sheet inside the hull:
[ul]
[li]not enough beef[/li][li]not precise and sensitive enought at a close hauled[/li][/ul]
b:
drum winch with exponential drum (with smaller radius near the close hauled):
[ul]
[li]more power at the close hauled[/li][li]better control near the close hauled[/li][li]but much to slow[/li][/ul]
c:
single arm winch (one for both sails)
[ul]
[li]enought power at the close hauled[/li][li]best control at the close hauled[/li][li]fast enought[/li][li]even sheeting in during a flying hull possible[/li][/ul]
d:
arm winches (one for each sail)
[ul]
[li]see above @‘single arm winch’[/li][li]trim option between both sails (jib slot)[/li][li]rig depower option (back winding, luffing main)[/li][li]supported manoevers by the sails (tack, bear away, main sheeted in during a gust at the running)[/li][/ul]
Thanks for posting these photos - and providing some info. Back about 2001 I managed to scratch-build a One Meter (MultiOne) trimaran. Photo shows a full size rig on it - but I also sailed it with a rig from a US 36/600 which was probably a B or C size rig for the 1 meter scale. Unfortunately I don’t have access to a bunch of build photos, and the hulls were given to a close friend. He doesn’t sail it much, so may ask for them back - restore/refurbish and sail it myself. It also has a Hitec 815 arm winch, but I was controlling both jib and main from it. At the time, multi-channel radios were too expensive so if I get it back, I may change to 2 channel rig control like you did.
Here is a photo of the boat with the full A size rig next to our old car. Gives a good idea for size.
Not yet, I use teflon grease. Capsized, when the cat is laying on it’s side, the servo is perhaps half way in the water. Next time I would place the main sail servo inwards, out of the hulls centerline.
I usually use a floating ball at the top of the mast. At my holidays at lake garda I don’t use it, I am a slow swimmer. Fortunately last year I had not one capsize at lake garda.
The step from b: to c: was a huge one to control the flying hull and to prevent capsizing
(although on a close hauled you have a little bit more time to prevent a capsize).
But sooner or later you have to tack and with a catamaran this isn’t funny anymore.
With only one sail winch for both sails I usually sheeted the jib too tight, hoping that the bow would be driven away to the new side during a tack.
But you could not rely on it and at a close hauled I got too much back winding at the main. Too often I was forced into a three point move during the tack and
being driven backwards is kind of annoying with such a fast sailboat.
So I took another arm winch on deck and now with the third servo I have got much more options to control the rig (d:).
The different sheeting is most needed during the tack.
The first half of the tack I usually sheet in the main and let out the jib to get more weather helm so I don’t need that much rudder during the tack.
The second half of the tack I sheet the jib in and let out the main a lot. As long as you don’t get any wind shifts or big waves during the tack it works quite well.
In stable light wind conditions I usually let out only the main to control the heeling.
It’s smoother and you don’t loose too much speed.
In high wind conditions I support the bear away with a fully let out main.
The jib keeps some speed in the boat and the luffing main won’t provoke a pitch pole.
My last vids were from wintertime and it was too cold for my windsurfing boots, not to mention bare foot
So I had limited access to the boat and didn’t change the sails’ trimm. But on those 4+ Bft conditions it was all too often nose-dive or capsize!
And with those waves I should have had more draft at the sails foot and more twist at the main sail.
So I hope my new d-rig is less critical,
just waiting for enought wind
the d-rig lever (mast lenght) seems to be too short.
so the good news are, I’ve got a d-rig that doesn’t need a floating ball (, because it’s useless ).
BTW:
with the small d-rig (and c-rig) I got my camera-app at it’s limits.
You don’t have an optical zoom and in bright sunshine you can’t see anything at the display.
While simultaniously sailing and capturing you’ll get blind shots most of the time
So actually the rigs are:
[INDENT]Main-Luff lenght/mast lenght:[/INDENT]
a-rig: [INDENT]145/165 cm (up to 2 Bft)[/INDENT]
b-rig: [INDENT]125/150 cm (up to 3 Bft)[/INDENT]
c-rig: [INDENT]108/135 cm (from 2 up to 4 Bft)[/INDENT]
d-rig: [INDENT] 80/100 cm (from 3 up to 4+ Bft)[/INDENT]
All sails are now multipaneled sails made with claudio’s gadget, battenfree and mounted with ‘heavy-duty’ 9 mm DS-tape.
)
