lots of yaw at high speed under power

[Hamin' X]

No instability on my 2001 X at any speed. WOT, 6k RPM gives me 18 kts w/boards up and at that speed, I can crank the helm from lock to to lock and she just leans into the turn and goes where I point her. This is with the mast up and the foresail furled and mainsail flaked on the boom. No problems. I think that I am on plane. If I am accelerating with the ballast tank full, she plows for awhile, although straight as an arrow, then as the tank empties, you can feel her drop in the nose and get up and go.

Oh yeah, 50 hp Suzuki.

~Rich

[mastreb]

No instability on my 2001 X at any speed. WOT, 6k RPM gives me 18 kts w/boards up and at that speed, I can crank the helm from lock to to lock and she just leans into the turn and goes where I point her. This is with the mast up and the foresail furled and mainsail flaked on the boom. No problems. I think that I am on plane. If I am accelerating with the ballast tank full, she plows for awhile, although straight as an arrow, then as the tank empties, you can feel her drop in the nose and get up and go.

Oh yeah, 50 hp Suzuki.

~Rich

Irrespective of arguments about what constitutes planing, you're definitely operating in planing mode. As for ballasted speeds above 7 below 13, the boat only oscillates in turns. On straight runs it would be perfectly fine.

[RobertB]

Yeah, hearin that. But I think it's going to be a while before my Admiral authorizes those kinds of boat-bucks. I still think there could be some improvements to be had. When I put small skegs on brackets on my M I could easily steer better, with better pointing (under power of course...). I'd like to upsize 6X and angle out diagonally somewhat. Maybe 30 deg.

Based on what you just said - there's good scope for some 30% bubble reduction.

Nice picture - looks like you are using the motor to plow a furrow. What grows best in driveway gravel?

How do the skegs work to affect the steering? Always looking for clever mods that do not require refinancing. Would dipping the rudders a bit do the same?

[BOAT]

Dipping the rudders is a no no. If the rudders drag in the water they can break - Roger said that they are not strong enough to be deployed partially. They must be all the way down or all the way up.

[Crikey]

Nice picture - looks like you are using the motor to plow a furrow. What grows best in driveway gravel?
How do the skegs work to affect the steering? Always looking for clever mods that do not require refinancing. Would dipping the rudders a bit do the same?

I've done both.



The last image shows how small the skegs really are, and imbalanced due to the mirror rudder brackets. It was a quick (not really) and dirty mod. They were grabbing water coming under the stern and turned with the outboard when connected. Straight lining and responsiveness improved over stock (none).
I'm making new brackets now for a truly symmetrical pair using half a Doel fin, angled outward so it can help with sailing as well. One of the reasons I lowered is to put a second bearing in for greater strength with this.
Ross

[Crikey]

Dipping the rudders is a no no. If the rudders drag in the water they can break - Roger said that they are not strong enough to be deployed partially. They must be all the way down or all the way up.

Absolutely! It will also bend the brackets, or get chewed by the propellor.

[Crikey]

Something approximating this.

R.

[BOAT]

Yeah, they do that on the big boats because there is so much lift on the rudder at that angle and the boat is so heavy that it puts a lot of pressure on the helm.

The MACS are really too light to need this kind of adjustment to the rudders. At least in my experience I have not noticed any lift caused by the rudders when I heel - I mean NONE - the wheel just stays in the same spot. I suppose if the steering cable broke the rudders might move.

In a really heavy boat the heel angle makes the rudder go though the water at and angle and creates a lifting effect on the part of the rudder that is now facing up, thus turning the rudder into a wing. It can really put a lot of pressure back on the wheel.

It's more of a problem on big boats (well HEAVY boats) and some even have HUGE wheels so big they go down below the cockpit or dual helms so on any tack the pilot can keep standing "on the keel" as they say while he is steering the boat - the angled rudders really help a lot and the dual helm makes it a lot easier to feel the effects of lift coming from under the boat. (You can feel it in the soles of your feet).

It's a neat feeling.

[Crikey]

I'm planning this as a power mode addition. Rudders up. Although having said that, when heeled while sailing, which is most of the time, one rudder is possibly partially exited and the other is angled well away from vertical as well as in the direction of slippage. When a conventional rudder is turned, at heel, it will also impart a rotation into its attachment point, as well as resulting in the desired change of direction. A rudder biased outward will effectively be vertical when the boat is heeled, and have more control even if one of them is out of the water. Many newer duals sport angled rudders, regardless of weight.
Mine will be too small, by comparison, with the primary rudders to show any large change while sailing. Just mainly while powering, I'm hoping. Because they're to be out all the time I have to be prepared to sacrifice them, just like a prop. Doels are about $35 a pair.
R.

[capncarp]

#1 he's talking about an X guy's. Different animal. #Dlanderson mentions that the board is suppose to be up over 5-6Kts. This is true. But, lets think this thru. The reason the board is there in the first place is to counter sideways movement. At hi speed the lift on the board would be so great the boat would list dangerously. If not break the board. This is not the case with the board down 3-4 inches. At that amount it just streamlines the hull and adds steering controllability. As I mentioned earlier, I don't sail anymore. I only power. The boat handles fine at hi speed with no wallow.
capncarp,
99

[BOAT]

I sailed a friends boat with those angles rudders and dual helm - man, that was a real nice ride! The helm is really light on the heel, and you can feel the boat turn around the keel when you change direction - it's really neat. Your feet on the deck are getting a totally different ride than the rest of your body because they are planted squarely on the deck. You can really feel what the boat is doing and what it's going to do.

The MAC is a strange beast - the rudders are HUGE! I mean they extend WAY down there!

I must assume the reason for that is because the boat is SO light. It just needs all that to keep the boat on a track. Once you get used to it it's not bad, but it's always a PITA in a following sea.

That's the sailing configuration that is the worst for those rudders - a following sea - I just don't know any answers to fix that problem. (Not yet)

[fouz]

No instability on my 2001 X at any speed. WOT, 6k RPM gives me 18 kts w/boards up and at that speed, I can crank the helm from lock to to lock and she just leans into the turn and goes where I point her. This is with the mast up and the foresail furled and mainsail flaked on the boom. No problems. I think that I am on plane. If I am accelerating with the ballast tank full, she plows for awhile, although straight as an arrow, then as the tank empties, you can feel her drop in the nose and get up and go.

Oh yeah, 50 hp Suzuki.

~Rich

What prop you using?

[Hamin' X]

No instability on my 2001 X at any speed. WOT, 6k RPM gives me 18 kts w/boards up and at that speed, I can crank the helm from lock to to lock and she just leans into the turn and goes where I point her. This is with the mast up and the foresail furled and mainsail flaked on the boom. No problems. I think that I am on plane. If I am accelerating with the ballast tank full, she plows for awhile, although straight as an arrow, then as the tank empties, you can feel her drop in the nose and get up and go.

Oh yeah, 50 hp Suzuki.

~Rich

What prop you using?

I honestly don't have a clue. It has three blades and it is black.

~Rich

[fouz]

No instability on my 2001 X at any speed. WOT, 6k RPM gives me 18 kts w/boards up and at that speed, I can crank the helm from lock to to lock and she just leans into the turn and goes where I point her. This is with the mast up and the foresail furled and mainsail flaked on the boom. No problems. I think that I am on plane. If I am accelerating with the ballast tank full, she plows for awhile, although straight as an arrow, then as the tank empties, you can feel her drop in the nose and get up and go.

Oh yeah, 50 hp Suzuki.

~Rich

What prop you using?

I honestly don't have a clue. It has three blades and it is black.

~Rich

Hmm. I got the same prop too! Just my rpms are different.

[Hamin' X]

#1 he's talking about an X guy's. Different animal. #Dlanderson mentions that the board is suppose to be up over 5-6Kts. This is true. But, lets think this thru. The reason the board is there in the first place is to counter sideways movement. At hi speed the lift on the board would be so great the boat would list dangerously. If not break the board. This is not the case with the board down 3-4 inches. At that amount it just streamlines the hull and adds steering controllability. As I mentioned earlier, I don't sail anymore. I only power. The boat handles fine at hi speed with no wallow.
capncarp,
99

The danger with having the rudders partially down, whether under sail, or power, is the increased load on the brackets and steering gear. The loads are huge with the leverage of the rudders extending straight behind the boat and you risk breaking something. Anyone that has had a rudder float up while under way because they forgot to cleat the down line (don't ask how I know ) can attest to this.

~Rich