Questions about tacking a catamaran

Two years ago we bought a 35 years old sagitta, designed by Richard Woods. In the following time we sailed her with pleasure a vew times. But never needed to tack her trough the wind. First time for us was last Saturday. What should I say: we couldn't make any tack without the engines. Even when I thought, we had enough free space we later touched the rocks.
I called someone whosails a catamaran of the same size like ours to ask him, what we did wrong. And he said, we didn't anything wrong. It's really difficult to turn a catamaran trough the wind.
Later I had a call to another person and he said, his catamaran would tack trough also by jib or mainsail only and also in the waves.
What might be the goal about those two absolut different informations and what can we do, change to make the boat behave better?
Please excuse my poor english. I hope, you understand, what I mean?

 

I never had much issue with tacking my cat. Are you backing the jib to help?

 

Yes, we alsways did so, but were standing in the wind. At navionics tracking I could later see, that we always sailed back, before going trough. It might be different by boat, depending on sailplan and lateralplan?

 

I have found Richard Woods easy to talk to and willing to help with his boats. Perhaps email him? The address is on the website.

 

Thank you for your answer. When Richard designed the Sagitta he was thinking about pure sailing on a lightweight catamaran. But since our Sagitta becomes older and older, she is also becomes fat and fatter. And preowners made some changes. So in short, she is not the same, as originally designed. One of the preowners said, she wouldn't sail without jib. And I think, it's true. Why?

 

Hi Arbalete, If I'm sailing a cat which has trouble tacking, I usually go off the wind a bit more for a minute before the turn, to get more speed, then do a quick turn, not a forceful slamming turn which stresses the steering gear, but a smooth fast turn. If that fails, then a controlled gybe is the next option to resort to. Stalling and then going backwards sometimes happens, which is annoying. A long keel (or two) is slower to turn than centreboards. Maybe look at the weight you are carrying; you may have soggy foam, or too much gear on board. Sometimes trimming bow down a bit can help to get around.

 

We have a Woods Flica and we do as seasquirt does - gain some speed before turning and back the jib until through the wind.
If I thought I wasn't going to get the tack done and was heading for rocks I would just start a single engine in case I needed it but this is rare!

 

It's really hard to diagnose a boat from a distance, and impossible if one doesn't know how she was modified. Instead I'll try to list some of the most common problems that seem to fit your simptoms, and be aware that often it's a combination not a single thing.
Old streched sails. Even if they still "look good" they may have distorted enough that the CoE has shifted and the boat has excessive weather helm without a jib. Blown out sails also don't develop enough drive to windward and you lack speed to carry you trough the tack.
Mast rake. Same problem as above, CoE isn't where it's supposed to be. Happens often when boats change hands with the mast down and the new owner doesn't know the correct angle.
Overweight. Often the weight piles in the rear where the hull is wider, immersing more of the stern and adding submerged area. This can shift the CLR and balance is compromised.
Modifications to keels/daggerboards and rudder usually shift the CLR.

What can you do: first and foremost you should notice how the rudder feels. The boat should have a very light helm, almost neutral, without any significant weather helm. Depending on how it feels you can try raking the mast to balance the CoE to CLR.
You should compare the existing sailplan and underwater appendages to the designed ones, to see if there are significant differences. If there are you can make a plan on how to correct the issue, either by rolling back the modifications or by making new ones.
Mark the existing waterline then empty the boat completely (everything goes out, including the liquid in the tanks). Compare the new waterline to the old, then put the boat on a diet and adjust stowage so that she sits more evenly. You can also go for a sail empty and see how she behaves. Remember she was designed for a total payload of 900kg, that's not much, weigh everything that goes back into the boat.

 

I think that it was mentioned about sufficient speed. No boat will tack without sufficient speed, regardless of design.

 

This is an important distinction, because pushing the rudder hard over before the boat starts turning can act as a break instead of redirecting the flow of water. Smooth, easy, and quick but not too quick.

Adjusting the traveler inboard before a tack might also help.

-Will