Mac 26 M Rudder speed restriction

[pokerrick1]

50 miles offshore i would have spare rudders on board, and also master sailing on course without rudders ...not as difficult as it sounds......

I, on the other hand, would NOT go 50 miles offshore

Rick

[BoulderBob]

Don't think I was going as fast as 6 mph when my rudders lifted the boat up off the trailer as I was pulling it up the ramp after the second time I sailed, the rudders just had a few good scratches. I never forgot to tie them up after that.

I seem to remember the dealer telling me the speed restriction was very important when using the engine and rudders in combination. He said while you almost never have the rudders down when using the engine, sometimes on a windy day it helps in steering in tight places or getting into a slip. He emphasized that turning sharply while using the motor above 5 mph could break a rudder. Perhaps that's where the restriction comes in.

[Doupirate]

Exactly.

I re-read the manual and the restriction applies only when motoring.

My mistake

[mastreb]

Not Trying to de-rail this thread .. But I have heard of people doing this on purpose and gaining an edge... a little speed.. I "think" I have done this or very close heeling over and running the rail in the water.. ( wouldn't we all like to be part of the MadMen so our buds would film us??) So I ask Mastreb.. are you one of those who has done this? I have heard it said that running just one rudder at a time will turn her faster than with two.... when sailing "hard/fast"????

The has two rudders. It only takes one to steer the boat perfectly well under moderate heel. The outboard lower unit makes a reasonable emergency rudder as well. Worst case, I've got two dinghy oars that could be tied down to serve as a jury rigged tiller. This is not a failure I would be worried about given all the redundancy available.

I've only done it by accident. Asked the admiral to lower the rudders once, and then found out an hour later that only one was down. Didn't notice a thing, the boat handled perfectly well. It was light air and not much heeling.

[dlandersson]

That might explain my a X left rudder broke last summer - I was moving pretty fast - 5.5-6 knots.

There is a 6 miles per hour (5.2 knots) speed limit on the rudders use.

It is quite easy to exceed that limit under sails, downwind, keel up, surfing on a 5 feet wave at sea.

I am wondering if that limit is applicable on the rudders in the full down position, the boat listing 20/30 degrees, or if it is designed to protect the rudders attachments in shallow waters when the rudders are largely horizontal, or when the boat is excessively listing.

The stress on the rudders attachement looks about 5 times worse when the rudders are partially raised, so that 5.2 knots limit should be about 1 knot with the rudders raised to a horizontal position.

Thank you for clarifying.

[Doupirate]

Were you under sails or motoring?

Were your rudders in the full down position?

Were you listing a lot?

I remain sceptical about a speed restriction applying only when motoring....speed is speed, loads are loads....

[Crikey]

Were you under sails or motoring?

Were your rudders in the full down position?

Were you listing a lot?

I remain sceptical about a speed restriction applying only when motoring....speed is speed, loads are loads....

I would venture to offer - speed does equal load! I was surprised to read the rudders even survived WOT when accidentally left in the down position! I don't think, given that, that they would have agreed too well with a rapid turn at speed.
Sailing at any speed must surely fit within the designed failure specifications. Any position back from deployed-vertical, sail or power, is asking for it....

[dlandersson]

Under sail, with a 25 degree heel - quite an experience. Did not notice the rudder mount crack until I was heading home.

Were you under sails or motoring?

Were your rudders in the full down position?

Were you listing a lot?

I remain sceptical about a speed restriction applying only when motoring....speed is speed, loads are loads....

[4sail123]

I have owned a 1998 26x for two years and been sailing many types of sailboat for fourty years. I think the major problem with the rudders down at high speed is contributing to capsize if ballast tank is empty. I owned a windrider rave hydrofoil and the lifting foils were much smaller than the rudders on the 26x. If the Mac 26 leans, the rudders start to act as lifting foils and could cause the boat to capsize and if tanks is empty not recover. I use full power on my honda 50 to empty tank with rudders down {lazy} , but am very carful about capsize potential. I looked at the manual for the X and it says to lift when powering only over 6 mph . No mentioning about sailing above 6mph I think because they say sail only with the ballast tank full. The boat is very tender sailing and rounds up when overpwered and unloads the steering system. Also same problem with center board, if it drops while at high speeds the boat could flip and not recover. On the M I would put a bolt in the daggerboard to keep it up for this reason if you plan to motor above 6mph without ballast offshoare, no way easy to do it on a X. I am more worried about the boat fliping than breaking a rudder. I hate typing, but nobody had brought up capsizing and thougt it needed mentioning. Phillip

[mastreb]

The reason is similar to what 4sale123 points out.

The rudders do indeed act as foils, but in the case that you are planing at speed and turning, the lift they produce is in the opposition to the turn-induced planing roll and would contribute to a reduction in roll. Furthermore, they reduce the stern side-slip during a turn that is required to keep the proper degree of roll as well. This puts an enormous amount of force on the rudders, reduces the effectiveness of the planing for a turn (increasing the overall turn radius of the boat), and could contribute to stalling the roll and flipping the boat (although I don't think a Mac goes fast enough for the rudders alone to cause a flip). This effect is why you must not power with the dagger-board down--it is a big enough wing to flip the boat if you turn against it while powering at speed.

This has nothing to do with sailing at any speed because the center of effort and force vectors are entirely different. You can't flip against full sails.

ON EDIT: You must not **plane** under power with the daggerboard down. Powering with board and rudders down below the displacement speed of 6.4 knots is perfectly fine, as is the mythical planing under sail.

[Doupirate]

NOW I understand. Thank you !

[Crikey]

Good point about the daggerboard safety pin! I don't really trust the rope all that much and Mastreb makes an excellent point why deploying under power would be a bad idea. I wonder if Roger's structural engineers designed the breakage limit in this component with this in mind?
I had thought about putting a safety catch on the daggerboard after I make a planned mod of attaching a small skeg to the bottom of it. Before I do this, spring will have to happen, in order to do some reworking of the fit with fresh fiberglass. I think this would improve handling under power but not present a risk of capsize as a deployed DB would do. With the pin I could raise the whole assembly clear of the bottom for trailer transiting. The mast would have to be down in order to raise it the extra six inches, but not the end of the world.

Ross

[Doupirate]

Rick wrote:

I, on the other hand, would NOT go 50 miles offshore

Given a favorable weather window, you are much safer 50 miles offshore than 5 miles offshore which is safer than 1 mile offshore, which is much safer than 500 feet offshore.

Beyond 50 miles offshore, a crossing exceeds 100 miles and the weather risk increases as you are at sea for longer than the 24 hours weather forecasts almost perfect reliability.

Catigale wrote:

50 miles offshore i would have spare rudders on board, and also master sailing on course without rudders ...not as difficult as it sounds............

The rudders are always supposed to be in neutral position if you have a furler and if the apparent wind is constant. I usually sail solo on a lake and routinely leave the wheel under sails to go to the can.

At sea, however, the apparent wind varies as your speed varies depending on what side of the wave your are. The rudders are then needed to stay on course.

[dlandersson]

Isn't it simpler to simply stand on the stern and pi$$ off the rear like a European fountain?

I usually sail solo on a lake and routinely leave the wheel under sails to go to the can.

[K9Kampers]

Isn't it simpler to simply stand on the stern and pi$$ of the rear like a European fountain?

Yes! Easier on an than an , I'd say, and not stream all over the transom and motor!