rudders down over 6 knts ????

[geocat]

Hi to all.
When the waves are coming sideways with motor and rudders up with speed over 6 knts my M26 needs heavy steering (autopilot is out of the question).
So my idea is to by a new set of rudders and cut them in half or leave the 3/4 of them I have not decide yet.
Any opinion or advice will be appreciated.
Thanks, George.

[tangentair]

Wow, first I assume you do not sail this boat, because you will need all the rudder length and then some when it heels if you do. Many people have replaced the stock rudders for this reason.
Second, you might post this question on the powersailer board, I almost didn't read it here.
Third, I am not very big on taking waves sideways, but I do not know your conditions and I have heard that they are different from what I am used to in the Caribbean. Still with the shallow draft of the MAC I would think that this is more than just a steering problem.

[NiceAft]

geocat said:

with motor and rudders up with speed over 6 knts

I don't undestand the statement How are you stearing


Ray

[RickJ]

I take it you mean motoring (not sailing) over 6 kts with rudders up?

First thing that will increase stability a lot is to lower a small amount of centerboard/daggerboard. That may be all you need.

How fast are you actually moving? There have been reports here of powering with rudders down at speeds up to 10 kts without ill effects. It seems the recommended 6 kts max. is very conservative, and 8 at least is not a problem - I've done that myself. I dont' think I'd risk faster than 10, but by that speed the steering is much more stable anyway even without rudders.

HTH, Rick

[March]

Why not pull the rudders half-way up, if the length of the rudderds seem like an issue? It shouldn't be though. The 6 mile limit, as Rick pointed out, is a conventional number. The idea is, if the boat is going fast, you don't need fine-tuning in terms of steering. Therefore, rudders might as well be up and you steer by using the motor. When you need fine-tuning (going into a marina, for instance) you will be going slow anyways, so the rudders may be down.
I use only one rudder when getting back on the trailer and it works pretty well

[Kelly Hanson East]

THe forces on the steering linkage and plates go way up, past the design limit, when the rudders are swung away from the brackets - unlike daggerboard-type rudders which are lifted straight up and down.

You will break something (probably steering gearbox) if you do this. Should be a couple of threads on the Fora about this IIRC.

[phil kelly]

Be very carefull if you use your rudders halfway down, I tested this and they hit the propellor when I turned either way.

[live2shift]

Agreed; you should never run with rudders in any position but full up or down due to the forces that would be exerted on them in the other positions that thee steering system is not designed for, but running with partial daggerboard causes no problem whatsoever

[March]

Phil.
You're right, if the rudders are not in a completely down position, or if they are not secured in a down position, they will hit the propeller when you turn hard right or left. It looks like they would clear the propeller if they are half way up, but they would strain the brackets, as Kelly pointed out--in case you make a hard turn under more than 8-10KTS of power. But why would you want to do that, with full rudders, or midget rudders, or rudders half down, in the first place? The rudders are designed to give optimal performance the size they are. IDA rudders reputedly perform better, but not because they are shorter.
I guess the only scenario where mini-rudders might perform better is if geocat wants to do a lot of power motoring and very little sailing--in which case he will miss more than half of the Macfun.
I shudder at the thought of changing rudders underway, but hey, it's a challenge.

[geocat]

Thank you all for replying.
The concisions of the problem are when motoring or under sails and motor in the area of 10 knts. I tried to lower a small amount of centerboard/daggerboard but nothing happened.
I do sail the boat but often I need to go faster. So I thought that with shorter rudders I will reduce the pressure to the rudders when powering without loosing completely the very good steering of the m26. Its all related write?
Anyway from your replys I realize that I was a bit conservative with the use of rudders only up to 6knts Since I don't need more speed than 10knts I will try 10knts with rudders down.
Thank you all.

[Bawgy]

Go ahead and order a new rack and pinion and cable for your steering as you will need it

[geocat]

Bawgy You clearly disagree. Why? You tried to power to 10 knts with rudders down and suffer a damage or your objection is more like <<leave it as it is>>?
To all:
I feel that the steering system of the M26 is suffering from the continuous steering. Also being in the sea with a lot of boats bigger and smaller I think that with waves coming sideways with rudders up the performance of the steering is poor.
Everybody in this topic writes that cutting a bit the rudders is wrong.
My questions is this:
Has anyone tried it?
Why cutting 1 foot (33cm) or a bit more will be a disaster?
In my mind when powering the shorter rudders will suffer less pressure and when sailing there will be enough surface in the water to steer

[March]

I would still think that Roger, the designer of this boat, knew what hewas doing. If he could have gotten the same results with shorter rudders, he would have certainly made them shorter. Less material, and less effort to pull them out of the water.

The rudders are mostly effective when it comes to sailing. That's why powerboars don't commonly have double rudders. The motor is enough to push the stern one way (forcing the nose to swing into the opposite direction). That may be confusing at times and may result in "oversteerring"--something you seem to mention in your message, too. If you have your rudders down, you will certainly have more control and will be able to fine-tune your trajectory. That is why most people here prefer the rudders down when returning to the trailer, or when docking.

Okay, so when you motor at 10 KTs, you shouldn't be needing all that "finesse". The larger and smaller boats are there in plain view to see. You have plenty of time to avoid them, even at lower speeds that put no extra strain on the rudders, brackets, cables, etc. So the idea of shorter rudders may be very helpful in cases where you won't be need them all. I don't think that you will find anybody who has cut their rudders just to see if the boat will steer better. It may steer better at 10 kts under power and perform much worse under sail. So why do it?

It's easy to cut your rudders, but putting back together again might be a bit of a challenge

[Alex]

O my God, ones again
Power "on" Rudders 'UP" This is a Law........
During the motoring, You can't steer your boat over 10knts with rudders down !!!!

Everybody in this topic writes that cutting a bit the rudders is wrong.
My questions is this:
Has anyone tried it?

Yes, tried to buy another, more longer for better performance !!!

[Hamin' X]

Geocat, While under sail, the rudder performs much more than just a steering function. It is designed to develop lift, which helps reduce heeling and provides resistance to making leeway. The rudders act in concert with the keel (dagger board/center board) and the water, to balance the boat against the wind on the sails. You can not shorten, or lengthen the rudders without affecting performance. The length of the rudders is just as much a part of the design of the boat as the length of your dagger board. If you shorten the the rudders you will have less pointing ability and possibly even develop more weather helm and round-up earlier, as the center of resistance will be moved forward.

Rich---Hamin' X---N7ZH