Hi all.
I'm a real beginner (not a year since I got my first cat) but started to race last week.
As expected we were last at the regatta. But enjoyed the race thing and noticed that there is full of room for improvement.
My question is regarding polars and VMG for catamarans (we sail an HC-16).

Do you have an idea as how close yo should sail to wind? (45 degrees?).

Do you have an idea of how differe the compass bearing from the true bearing (GPS)?

I know that the boat type, setup and handling will have tremendous effect on the recommended angle. I know also that wind and wave conditions have also a big effect.

I look for rules-of-thumb or personal preferences...

Thanks all.

with regards to sailing upwind....

Its really different for each boat. I've never sailed on a H16... but heres the rule of thumb for cats... NEVER PINCH.

If you're racing in a mixed bag with some monos on the same course and you see them pointed right at the weather mark, its tempting to try and show them up. It just wont happen. You relegate the greatest benefit of the catamaran when you pinch. Foot off, get that sail flat as possible, read your telltales and get speed. Plus it makes tacking so much easier when you're going fast

Ok. That far.

But is it 45 degrees a good angle?. Or in other words: Can i asume that layline is OK when the A mark is 90 degrees from current bearing. (that being easy to check).

How do you do when you are first to aproach the mark?.

Me, being after most of the fleet, I can see their guessed layline and tack when I see'em and the mark in line...

This is what I miss most about the old days!! If you had asked these questions on the beach back in the '70s, an expert sailor would have taken time, courteously, to explain you have the cart before the horse.

As a newcomer to the H16, you should first be aware of:
Weight distribution- skipper and crew
mast rake
batten tension and location of the "pocket"
and, probably rudder rake.

Come on! Some of you folks that are still doin' it, give this guy a hand!

Dont worry. I've already read and experimented with ALL that.

I know that i'll really improve by better handling. But that's something that takes time and time and time.

The question i firstly asked was completely independent. I ask out of curiosity and not hoping to get me a better final position in the next race.

Maybe you would get more responses if you post this on the Hobie 16 forum, as well. I know the Hobie 16 does not point as well as boats with boards, so it is going to be more than a 90-degree angle when you tack to go to the mark.

I also know that you are not going to learn much if you are using a compass for closed-course racing. Get the thing off your boat and watch what the other boats are doing.

Where do you sail?

Mary,

OK, so, a board cat tacks for a 90-degree.
(And for a h16 i should allow for a wider angle, 95? 100?)

The question was general, i'm also interested on comments for other cats.

What about the drifting angle? asuming no currents, no waves, ..., ...

Knowing about all these things will help me to decide if I've to buy the compass, the GPS, or neither.

Thanks,
aestela.

ps.: Mary, I sail in Valencia, Spain. Host of AC'97. Sunny and windy enough all year round.

don't buy either of them for round-the-can racing.

if you get it working, the compass will be a crutch that you rely on, you'll only be as good as your compass allows. You'll never be as successful than if you just learn to "eyeball" it

Dude - welcome to the game. It sounds like youve really got the bug, and that's cool. While I know my way around the front of a boat, I am a begginer-level skipper, too.

I have a small boardless boat also that sails very similarly to the H16. I'm guilty of often pinching unless I REALLY concentrate on how the boat is feeling. I always go past that 90-degree point until I need to almost look over my OTHER shoulder to see the upwind mark. I'd say this usually puts me in the 100-110 degree range. Assuming you have an accurate waypoint for your upwind mark, this would be when the VMG becomes a negative number after being zero for a few moments. I take a deep breath, focus on boatspeed, and make the best tack I can. I'd rather go a boatlength or two too far rather than rush it and have a bad tack.

I find beating upwind to be much more difficult than running, so this is where I need the most practice. Nothing feels better to me right now than getting upwind without a blown tack, stalling, and without drifting into the mark because I tried to pinch it off at the end of the leg.

Good luck!

ps - I have a hand-held GPS with an electronic compass. It has helped me a great deal. A lot of guys my age do better with anything in life that can be made to seem more like a video game.

Aestela
First I would recommend that you have a wind indicator on the bridle. The downwind rule of thumb on a Hobie 16 is to keep the apparent wind at 90 degrees. (if it’s windy and you want to de-power bear off)
Upwind is trickier. When there is good wind (double trapping) you want to make sure you bear off enough to get the boat going fast. Basically if you are slow first try bearing off and if that doesn’t work it’s a sail trim problem.
When it’s lighter air you do need to pinch a 16, but not too much. The ‘not too much’ part is the trick. If you pinch too much you slow down and never get going again. You need to develop an instinct so that you know when you’re going to slow down before you slow down. Just before you slow down you should ease the main a half inch and bear off three degrees.
A Hobie 16 tacks in about 100 deg when it's realy windy and realy light down to about 90 deg when it's full power conditions.

Found a polar diagram for ten knots, see attached.

http://www.west.net/~lpm/hobie/archives/v1-i3/feature3.htm

For Rhodysail: I cannot trust these polars. A bit too perfect values for 45, 60 and 75 degrees, if you know what I mean.

For all:
About the compass. I see very different points of view.

Asuming you're not for long distance trips, do you use a compass? Training? During the race to track windshifts?

Where I sail everybody has a compass on board. I'm now more busy trying to get speed and watching what the other boats are doing, but I guess that maybe in the future I'll have time to check the compass.
What for????

Thanks for your replies

It's difficult sometimes to realize a wind shift if you don't have a good stationary point of reference on nearby land. A compass can help you quickly identify that you are sailing a slightly different course due to a change in the wind direction. This might mean that it's time to tack. It can also help make sure that you are sailing the proper angles and are not footing or pinching too much by watching your tacking angles (although it would take a lot of experience to really understand what these angles are in different wind strengths).

I only glance at the compass once in a while. On my GPS, I have the speed, VMG and compass all on the same screen. The compass and VMG tell me when I've hit the corner and I'm on the layline. I use it more in the beginning of the season when I'm knocking the rust off, and less as I get comfortable with eyeballing it. Also is a good check for persistent shifts or major current effects.

I used a single Suunto compass with adjustable tacking bands for many years, and then switched to two Suunto jr compass's for reasons below. I found it worked great on flat water, but to confusing in the ocean. Basically, the tacking angle on flat water was 90 degrees, and in the ocean it was 110 degrees on a TheMightyHobie18.

It became confusing in the ocean when the waves would NOT come from the same direction on the race course as the wind during the day. The waves continually change their height, angle and spacing in relation to the boat's sailing angle throughout the day, making one tack's VMG appear on the compass better on the other tack constantly change. The sea state/angle changes during the race, the tacking angle can be 50 degrees off the nose on one tack, and 60 on the other, then as the waves build/change to 50 and 65 equals 115 degrees.

Sea state/wave angle affects your tacking angle. On the race course in the ocean with no land bearing, when your compass shows a 5-10 degree change you need to know if this change is due to the wind OR sea state/wave angle, because when you tack your compass reading will be WAY OFF due to sea state and wave angle on the other tack. The sea state/wave angle can change with proximity to the shore. The wave height and distance between waves can change due to depth of water which could vary over the race course.

For me, there were to many constantly changing variables involved adjusting the tacking angle in short course coastal racing trying to figure out why it changed from one tack to the other due to sea state/angle, OR did the wind change? A compass that can adjust the wind direction for each tack is needed to compenstate for the sea state/angle on each tack, or two compasses would be more accurate. I'm not saying it can not be done, but it takes a lot of racing PRACTICE, and to know when NOT to use the compass. As it has been said many times before, "keep you eyes out of boat".

To selfteach some things to look for when you keep your head out of the boat try a racing simulator such as at poseysail.com

For long distance sailing using a VMG reading (velocity made good) on a GPS is better tool to use when deciding which tack it more expeditious.

If your just starting.
Get a Telo-cat Bridle Vane (wind vane).
It has arms that you can line-up the windvane with
to help keep the same angle to the wind.
The arms have 3 adjustment slots.
If the water smooth use the inner holes.
If its rougher use the center holes. you
will foot more.
It will help to get you in the ballpark but
learn the telltails.
Got my 1st H-16 in 76. Now on #4. Like to race
but spend most of the time with the kids.
Just have fun. Lots of more tect boats out there.
Most bigger but....Sail a reach with the wind 18-20 knts and few of the newer boats will run with you.