Cant tack.

Hi. I have aquired a crest cat with a windrush sail, mast, boom and shallow rudders.
Im experienced in cat sailing but am struggling to tack. Its heavy on the helm and with the rudders hard it still wont bear downwind unless i ease the main alot. I tried adjusting the forstay tension without success.

Thanks

Has the rig got a little jib you can back wind? Makes a big difference with my cat

Throw the main sheet off so the main swings right out and tighten once tack is completed. Start by making bigger tacks than needed and bring them tighter as you get used to it. Also keep rudders over (sounds obvious but often half through tack helm position is lost).

Which way is it heavy on the helm? Does it want to swing upwind? Or downwind?

cats really aren't known for their ability to tack well in the first place, having two hulls and all.

strange that you're struggling to tack, as well as having trouble swinging offwind. The two symptoms don't usually go hand in hand.

As above. Mast rake is crucial, as are rudders, backwinding the job will help.

I'd add, is your weight too far back keep the hulls balanced fore and aft, are you trying to tack too sharply. It needs to be wide and smooth so the rudders don't dig in and act as brakes. If you're tacking smoothly at speed and still can't head into the wind then the rig is out of balance. Add rake, Windys had quite a lot. If that's not helping. Then the rudders are being overpowered.

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nswsailor said..
What rake do you have on your mast?

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Harb said..

lLiam said..
Hi. I have aquired a crest cat with a windrush sail, mast, boom and shallow rudders.
Im experienced in cat sailing but am struggling to tack. Its heavy on the helm and with the rudders hard it still wont bear downwind unless i ease the main alot. I tried adjusting the forstay tension without success.

Thanks

Its likely caused by the rudders acting like brakes when pushed hard, if you want it to tack make yourself a pair of naca profile deep blades or modify some from a Hobie 14 . A jib would also help a bit too.

Ill prob make some blades. Thanks. I tried with and without the jib without any significant difference. But the jib/forestay is too big for boat i think.

How much is "a lot". Many people try to keep the sails sheeted in too tight downwind. Is the front of the sail on the verge of luffing at all times? Unless you can see the front luffing if you ease about a foot of sheet, it's probably too tight.

My first sailing experience back in the seventies was memorable.
As QANTAS crew we arrive in Honolulu and a crew member Trevor Aldous suggested we hire a cat and go sailing.
Our third crew member was a flight hostess named Sharman Whitehead.
We were having a wonderful time running and reaching off Diamond Head.
Eventually our time was up and we decided to head back for the flight to San Fran a few hours later.
This was when our troubles started. We could not tack as our cat's hulls had been filling up with water.
If that was not bad enough Diamond Head was nowhere to be seen and these were the days before mobile phones.
Well would you believe another cat appeared from the boat shop looking for us.
We swapped cats and eventually got back in time for our flight.

If Trevor is out there I would like to make contact with him.
I understand he sails with the Drummoyne Sailing Club

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lLiam said..

Subsonic said..
Which way is it heavy on the helm? Does it want to swing upwind? Or downwind?

cats really aren't known for their ability to tack well in the first place, having two hulls and all.

strange that you're struggling to tack, as well as having trouble swinging offwind. The two symptoms don't usually go hand in hand.

It is odd.
It will go downwind only if i ease the main alot. If I dont ease it enough the rudders drag on an angle whilst I go straight.
Same as tacking although alot of thats probably operator error.

Thanks for help.

G'day Iliam,
Just an interesting point here, dragging rudders will force the boat to go the opposite way to which you intend it.
You're on starboard tack. You want to bear away to port.
You pull helm up to your chin to force the bear away, causing the rudders to drag.
The boat doesn't want to bear away to port, and so we pull even harder on the helm.
The boat will instinctively try to head to starboard, reversing your desired direction.

I'm exaggerating, but imagine grabbing a fistful of weather helm really quickly . This will cause the following to happen;
a) Pulling the them towards you causes the rudder to gain horizontal lifting force and and drive for the surface.
b) This rotates the transom up and to starboard.
b) The bow goes the opposite and digs in.
c) The heel of the bow to leeward also digs the bow in.
c) The mast rotates to leeward, which
d) This moves your wetted surface area forrard and to leeward. The sailplan is still where it was, so the drivng force is now behind the pivot point of the boat.

Result: Boat will try to sail to starboard. With full helm to port.
The opposite has the same result just inversely, pushing the tiller to leeward will drive the stern deep , mast rotates over the top of you to windward, and the boat goes nose high, the bow then falling away downwind. So, dragging a tiller to leeward forces the boat to want to bear away, not head up.

Try not to drag rudders, you're forcing the boat to do the opposite of what you want. .You're much better off giving them a violent shove in the opposite direction to regain control just at that moment before it all becomes too late

.




The above is a pic of the aforementioned starboard tack, and you're trying to bear away to port by dragging the rudders with a fistful of weather helm.
The more drag from the rudders the more pronounced this effect is eg: the boat instinctively trying to turn to starboard.

I don't know how much of this applies to cats mate, but they are still sailboats and follow the same laws of physics, so I assume it is the same thing. Smarter chaps than I might be able to explain if this is relevant still for cats?
Its interesting none the less to understand what the heel and rudder angle does to a boat, sometimes not what we think!
Cheers,
SB

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shaggybaxter said..

lLiam said..

Subsonic said..
Which way is it heavy on the helm? Does it want to swing upwind? Or downwind?

cats really aren't known for their ability to tack well in the first place, having two hulls and all.

strange that you're struggling to tack, as well as having trouble swinging offwind. The two symptoms don't usually go hand in hand.

It is odd.
It will go downwind only if i ease the main alot. If I dont ease it enough the rudders drag on an angle whilst I go straight.
Same as tacking although alot of thats probably operator error.

Thanks for help.

G'day Iliam,
And the problem is exactly what? I definitely can't go downwind either by using just the rudders only. In actual fact, they're useless without trim.
That's what good boats should be, or your rudders getting too big.
The correct way to bear away is to do exactly what you're doing, ie: ease sheets, not move the rudder, so you're doing it right!
The mainsheet is my first thing to ease to bear away. Done right, you're wickedly fast into the run that is waiting.
Use your weight and the lines to steer, the rudder is minimal input only. Don't blame the boat for actually being good at what it does :)

Makes sense. Thx. Sounds like something Ive just got to go practice.

Here's another way to look at it, the boat will also try and balance itself at the sail plan to its optimal wind angle.

Your punting to weather close hauled. Boat's tracking straight.
You try and steer the boat off the wind with the rudder, no sail ease. ,
You're increasing the angle of attack of your sails, and the boat is now unbalanced. Its overpowered.
The boat try's to restore its sense of balance, and fights you by driving back to weather, whilst your forcing it off the weather with the rudder.
Dragging.

Instead, don't touch the rudder, and ease the main. By easing the main, the boat will automatically bear away from the weather by itself to try and restore its balance point, or that optimal angle of attack, of the sail plan again. Do it slow and smooth, and the boat will obediently follow it around like a puppy dog.
And you didn't even touch the rudder to change direction.
Win win!