Catamaran Trim Advice

[HabibiDah]

Anyone have any constructive advice on what I could do to trim this better?

On one hand, 8.2 knots on a beam reach in 19 Kts of wind doesn't seem bad. I feel like I am up against the hull speed (for you naval architect types out there), but I've got a 6 degree lee helm in. Yes, fighting a lee to windward flowing current, but still...I suspect the rotational force of the main while on the beam reach is causing this without and counteraction from the jib. (Again, because we are reaching and most force is longitudinal rather than lateral.

Still, I feel that sailing is a constant learning endeavor and I'm open to any suggestions.

Thanks!

[thinwater]

Originally Posted by HabibiDah

Anyone have any constructive advice on what I could do to trim this better?

On one hand, 8.2 knots on a beam reach in 19 Kts of wind doesn't seem bad. I feel like I am up against the hull speed (for you naval architect types out there), but I've got a 6 degree lee helm in. Yes, fighting a lee to windward flowing current, but still...I suspect the rotational force of the main while on the beam reach is causing this without and counteraction from the jib. (Again, because we are reaching and most force is longitudinal rather than lateral.

Still, I feel that sailing is a constant learning endeavor and I'm open to any suggestions.

Thanks!

a. Do you mean true or apparent wind on the beam?
b. What sails?
c. How are you trimmed?

Most obviously, reef the main. Lower the traveller. Are the sails stalled or are all of the telltales flowing? Though much depends on the keel position, off the wind you typically want bigger head sails and a smaller main.

You should be able to find all of this in a good book on sailing. I learned sailing dinghies 40 years ago--they are better teachers than a cruising cat.


http://sail-delmarva.blogspot.com/2010/10/balance.html

[catsketcher]

Thin water is on the money here - cats are great cruisers because they are so easy to sail, but lousy at making you a better sailor. Dinghies are your best friend at that, try not sheeting properly on a dinghy and you can't even bear away in over 12 knots.

I think you have weather helm - which means you have to steer the boat to leeward.

I like to trim my sails reaching by a simple method. Get going on my course and trim the jib so that the telltales 1/3 of the way up the luff are set - both flowing aft.

Then with after having eased the main off, trim it on until the telltale on the leech of the sail (about 1/3 of the way down the leech) starts to flicker and hide itself behind the leech.

You should drop the traveller on a reach to ensure you reduce twist and don't oversheet the bottom of the main.

This works on every boat I sail - skiffs, monos, cats.

Post some video or shots for better diagnosis.

[Sparx]

Cat sailor here.

8.2 knots in 19 TWS @ near 120 apparent wind is not bad. But I would not be surprised to get another knot or more with some tweaking. This is why you posted of course.

The boat is heading up because of more force in the main than jib, as you surmised. If you have dagger boards drop the leward board a bit. Also letting the traveler out may help. The next step is to reef the main. Don't be surprised if the boat is just as fast reefed and much more comfortable.

You are right on point with trying to make the helm neutral.

[Bobby Lex]

Originally Posted by HabibiDah

I feel like I am up against the hull speed (for you naval architect types out there)....

I don't think that the conventional "hull speed" formula even applies to your cat because it's probably not a true displacement hull.

On the other hand, I suppose what you are really asking is how to squeeze more speed out of your boat regardless of what category its hull type falls into.

IMO the "sail-a-small-boat" advocates here are right. As a general rule, the smaller the boat the more responsive it is to adjustments in sail trim. So a great way to develop a "feel" for proper sail trim is to sail boats that respond quickly to such changes.

The other thing about sailing small boats is that you generally don't have instruments to tell you how hard the wind is blowing, or from what direction; and you don't have an autopilot to steer for you. You actually learn to steer the boat over the waves by feel, and how to make small adjustments to keep her moving as efficiently as possible. You actually learn to feel where the wind is coming from and you learn to watch your telltales to guide you how to trim your sails perfectly.

When I was young and learning to sail, I owned Hobie Cats (16' and 18') and sailed them a LOT. You can really learn to sail on a boat that is as responsive as a Hobie. You, too, might want to spend some time practicing on a small catamaran and hone your sailing skills that way.

There's a lot of debate back and forth on these forums (and others like it) about which hull design is better and which boat is faster and fin keels vs full keels and the like. But you hardly hear anyone mentioning the sailing skill of the person at the helm of these boats.

A good sailor on a "slower" boat will likely be able to go faster than a poor sailor on a "faster" boat. The bottom line is that it's not about the boat, it's about the sailor. So wanting to improve your sailing skills is always a good thing -- and I applaud you for posting your desire to do just that.

Bob

[fxykty]

Originally Posted by Bobby Lex

I don't think that the conventional "hull speed" formula even applies to your cat because it's probably not a true displacement hull.



On the other hand, I suppose what you are really asking is how to squeeze more speed out of your boat regardless of what category its hull type falls into.



IMO the "sail-a-small-boat" advocates here are right. As a general rule, the smaller the boat the more responsive it is to adjustments in sail trim. So a great way to develop a "feel" for proper sail trim is to sail boats that respond quickly to such changes.



The other thing about sailing small boats is that you generally don't have instruments to tell you how hard the wind is blowing, or from what direction; and you don't have an autopilot to steer for you. You actually learn to steer the boat over the waves by feel, and how to make small adjustments to keep her moving as efficiently as possible. You actually learn to feel where the wind is coming from and you learn to watch your telltales to guide you how to trim your sails perfectly.



When I was young and learning to sail, I owned Hobie Cats (16' and 18') and sailed them a LOT. You can really learn to sail on a boat that is as responsive as a Hobie. You, too, might want to spend some time practicing on a small catamaran and hone your sailing skills that way.



There's a lot of debate back and forth on these forums (and others like it) about which hull design is better and which boat is faster and fin keels vs full keels and the like. But you hardly hear anyone mentioning the sailing skill of the person at the helm of these boats.



A good sailor on a "slower" boat will likely be able to go faster than a poor sailor on a "faster" boat. The bottom line is that it's not about the boat, it's about the sailor. So wanting to improve your sailing skills is always a good thing -- and I applaud you for posting your desire to do just that.



Bob

Conventional hull speed formula does apply to a relatively heavy and wide-hulled like the Lagoon that the OP has. There’s not quite the bow wave hole that an equivalent length monohull would have, but certainly still there on this kind of cat. So 8.2 knots is probably about right for just exceeding hull speed and you would need a bunch more power (more sail area) to go much faster in flat water (not counting surfing). A broad reach in 20 knots of wind should be ideal for attaining maximum speed.

[Redreuben]

@HabibeDah, Do you seriously expect useful advice without even mentioning the model of boat or heaven forbid a picture of the sails set on the course described ?

[fxykty]

Originally Posted by HabibiDah

Anyone have any constructive advice on what I could do to trim this better?



On one hand, 8.2 knots on a beam reach in 19 Kts of wind doesn't seem bad. I feel like I am up against the hull speed (for you naval architect types out there), but I've got a 6 degree lee helm in. Yes, fighting a lee to windward flowing current, but still...I suspect the rotational force of the main while on the beam reach is causing this without and counteraction from the jib. (Again, because we are reaching and most force is longitudinal rather than lateral.



Still, I feel that sailing is a constant learning endeavor and I'm open to any suggestions.



Thanks!

Please clarify what you mean by “6 degree lee helm in”; it seems that you mean that you are steering with a constant 6 degrees of rudder angle turning you to leeward. Is that the case? If so, that’s not a big deal on a broad reach with a fair bit of power, though as others have pointed out you could try easing the main sheet and/or moving the traveller closer to centreline to allow the top part of the main to twist off and generate less power. Do you have a square top main?

Is your jib properly trimmed - all luff telltales flowing aft and sheet lead forward to prevent the top twisting off? Can you unfurl the jib to make it bigger? Or you could set a gennaker - the larger size sail up forward will help counteract the force of the mainsail.

Note that the leeward to windward flowing current has no effect on your steering.

[Factor]

Originally Posted by Redreuben

@HabibeDah, Do you seriously expect useful advice without even mentioning the model of boat or heaven forbid a picture of the sails set on the course described ?

His profile thingy to the left of his post says Lagoon 46

[fxykty]

Another thing to check is your rudders’ alignment and your rudder angle indicator. Both rudders should be parallel to each other. It’s a good idea to mark the quadrant and shaft when each rudder is fore and aft centred.

Rudder angle indicator is usually taken on one side only. Confirm that it shows centred when the rudders are centred. Adjust as needed.

[django37]

Tie a block to the spring cleat and sheet the foresail out there when on a beam reach

[Snore]

First +1 on the snatch block mounted to the beam cleat. It will get the hook out of the jib.

Did you reef? At 19, most cats should have a single reef. Along the same line- how much rudder did it take to hold a course?

Finally, if the sails have tell tales (2-3 rows) you can check your trim. Unfortunately, most sailors never learn to use them. Suggest you Google Arvel Gentry for a few lessons on sail trim and tell tales.