"Laser Aligned Foils"

vox

Member
62
0
I see this comment sometimes on ads for boats. Can anyone explain to me like I'm five what this really means?

 

couchsurfer

Super Anarchist
18,322
134
NA westcoast
.

.....sometimes lasers come with the cb and/or rudder not being properly square to the boat,, ie measure fro gunnel to bottom tip is different side to side,,, or the cb twisted in position.

I once had a boat where the CB was canted in such a way to favor starboard tack,, it was helpful at a worlds qualifier in San Fran cityfront,, but usually it's better to be as square as possible.

.......adjustment..... legally, there's very little that can be done to the CB, 'cept measure before buying. If the cb is off square, the best yer can do is align the rudder with the canted cb.

The rudder can be easily squared up by adjusting a gudgeon.

 

WCB

Super Anarchist
4,405
863
Park City, UT
It's not just at the AC level, it's been done for years. An engineering buddy used a transit to align his 110 keel and rudder. I know of J24s that had this done years ago. I was planning on hiring an engineer to sight a keel and rudder from a rebuild I'm doing.

 

Rantifarian

Rantifarian
It's not just at the AC level, it's been done for years. An engineering buddy used a transit to align his 110 keel and rudder. I know of J24s that had this done years ago. I was planning on hiring an engineer to sight a keel and rudder from a rebuild I'm doing.
Pretty common for doing yachts too. Tape measure from the masthead is pretty error prone at long lengths,and the deck is more likely to have assymetric areas. If you get your rig base settings aligned with keel, and rudder aligned too, everything should be hunky dory.
 

olivers

Member
122
0
Take home builder's laser, remove some (boat) builder's tolerance associated with centerboard and rudder alignment and psyche yourself on the basis that you've done everything you can ...

 

JimC

Not actually an anarchist.
8,172
1,064
South East England
I suppose the "like I'm 5" summary comes to:

The foils on a boat need to be aligned, the more accurately the better. In the old days we used a piece of string as a reference to get a straight line. Nowadays most folk use cheap laser levels cause its easier to be more accurate.

 

Steve Clark

Super Anarchist
Do the foils really need to be aligned?

On multi hulls, certainly you like things not to be fighting each other, so if your dagger boards were toed in or out you might have a beef.

I usually sail with the rudders toed in just a bit so that the windward rudder is at ) angle of attack when the leeward rudder has enough helm to counter the weather helm of the rig. I do this by making sure the wave on the windward board is equal on both sides.

On a monohull:

Getting the centerline of the hull and centerboard aligned fore and aft is probably a good idea, but the notion of gybing boards suggests that a degree or two either way doesn't matter that much.

Being off axis will manifest itself as different amounts of weather helm on different tacks. If the weight of the helm is equal or close to it on each tack, you are fine.

The rudder turns, so it doesn't have to be aligned.

In a vertical axis,. it is somewhat dubious as well.

Bill Beaver once asked, "When was the last time your boat was straight up and down?"

The same logic applies to having the masthead centered above the hull. It probably matters some, but it isn't the kind of thing that rockets you to the head of the fleet. On a boat with head sails, the biggest difference will be manifested in the jib leads. The jib clew will be closer to the deck on one tack than the other, so if you see yourself having to put the leads in different places to make the jib set the same on either tack, it's likely your rig is tipped.

This is good fun stuff to measure and obsess about, but it isn't a magic bullet.

SHC

 

JimC

Not actually an anarchist.
8,172
1,064
South East England
This is good fun stuff to measure and obsess about, but it isn't a magic bullet.
No, but on the other hand having different settings on different tacks is the sort of thing that would really psych me out.

Another thing to bear in mind is that I've never worked on a boat that was truly symmettrical. Its always been a case of establishing the best datum I can and then working from that.

 

DRDNA

Anarchist
573
13
Ventucky
This is good fun stuff to measure and obsess about, but it isn't a magic bullet.
No, but on the other hand having different settings on different tacks is the sort of thing that would really psych me out.

Another thing to bear in mind is that I've never worked on a boat that was truly symmettrical. Its always been a case of establishing the best datum I can and then working from that.
I'm always setting everything differently on different tacks as I only sail in the ocean, and one tack is usually almost sideways to a swell, and the other tack is almost always into a swell(upwind)Of course, on a usual day, there are three or more swells engaged in destructive and constructive wave interference, and wind chop, powerboat wakes, and etc.

 
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cantp1

Anarchist
502
3
Montreal, QC
Do the foils really need to be aligned?

On multi hulls, certainly you like things not to be fighting each other, so if your dagger boards were toed in or out you might have a beef.

I usually sail with the rudders toed in just a bit so that the windward rudder is at ) angle of attack when the leeward rudder has enough helm to counter the weather helm of the rig. I do this by making sure the wave on the windward board is equal on both sides.

On a monohull:

Getting the centerline of the hull and centerboard aligned fore and aft is probably a good idea, but the notion of gybing boards suggests that a degree or two either way doesn't matter that much.

Being off axis will manifest itself as different amounts of weather helm on different tacks. If the weight of the helm is equal or close to it on each tack, you are fine.

The rudder turns, so it doesn't have to be aligned.

In a vertical axis,. it is somewhat dubious as well.

Bill Beaver once asked, "When was the last time your boat was straight up and down?"

The same logic applies to having the masthead centered above the hull. It probably matters some, but it isn't the kind of thing that rockets you to the head of the fleet. On a boat with head sails, the biggest difference will be manifested in the jib leads. The jib clew will be closer to the deck on one tack than the other, so if you see yourself having to put the leads in different places to make the jib set the same on either tack, it's likely your rig is tipped.

This is good fun stuff to measure and obsess about, but it isn't a magic bullet.

SHC
Well put, Steve.

I've seen LOTS and LOTS of 49er guys put a huge emphasis on centering boards, mast steps, chainplates, etc. Whole lot of good it's done them! I've had conversations with medalists who essentially say what you're saying - if you think you need it done to be fast, then you need it. So if you're a younger sailor wondering whether to do this or not, I'd say No! Just go sailing instead.

 

Reht

Super Anarchist
2,758
6
In the 9ers, I always figured I could eye-ball it. As long as it looked straight and with both boards in I couldn't see the rudder behind the daggerboard from the front or daggerboad behind the rudder from the back, I figured it was all perfectly acceptable. Having a twisted or tilted board can cause the boat to pull one way and cause more/less weather helm between tacks, but to notice you'd have to sail a lot, and compare almost back-to-back with other boats before the imbalance becomes apparent. If you're racing at the thin end of a fleet and need that extra 1% then maybe it's worth considering. After new sails, time tuning the rig, replacing aged lines, etc.

 




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