Becker rudder

[fonsie]

I am an Danish owner of af LM 27 - (1977) and I have an idea to put af Becker rudder on my boat. Are there some one with Pictures, drawings for this project?  will this rudder give the boat a better shift for sail,  tanks.

[jandane]

Nope....A Becker rudder or hinged rudder only gives you a higher degree of rudder angle. Normally the rudder can be turned to 30-40 degrees angle. A Becker rudder can due to the flap system give an angle of attack on up to 60 degrees thus giving the ship a faster turn rate. The system is mainly used on very big commersial ships as the cost of the rudder prevents it being used by normal sailors like us. If you install it on your LM27 you most likely will have a good effect on very low speeds forward. When reversing, the pressure on the rudder will be very high and my best guess is that the normal rudder mounts will be ripped off. You have to completely redesign the rear part making new calculations. Also be aware, that the Veritas approval of the LM 27 most likely will vanish as you have made constructional changes. If you want better handling under sail, the best way to to trim your rig and sail. Having done so, you will be able to steer the LM27 with two fingers on the tiller. If you want better maneuverbility at low speeds my proposal is you install a bow thruster It works both when forwarding and when reversing an will only cost you 10-15000Dkr. If you want a little more rudder action, I am aware pf one or two Danish LM27 owners have installed a bigger rudder with an extension in front of the rudder axle, meaning between rudder and screw, and they also have increased the area of the rudder upwards from the backpart up to the rearpart of the stern. See attached picture

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[fonsie]

hey jandane

thank you for your advice . I had a suspicion that it was not just to put the flap on the main rudder ... I have seen more pictures like those you have put in . I think I'll look me around on the ports here in the winter and find perhaps a LM27 with such rudder and therefore look the owner just over the shoulders

[pengwyn]

In case someone is still interested... I have a becker-rudder on my LM-27. Probably the one, that could be directly ordered from LM. Under sail it increases your turn-rate significantly , as long as you make at least approx. 2 knots - but at the price of acting like a brake, if used at max. rudder angle. at no speed also a becker rudder can't turn the ship. under motor the rudder behaves different. the water stream from the propeller will be deflected by the rudder flap in a way, the boat can be turned on a spot - no thrusters required. It also allows the LM-27 to do sharp bends, like a go-cart. going astern under motor takes a little practice and you have to make sure, you start with a straight ahead tiller position. But with a little practice going reverse can be smoothly controlled with predictable results. In my opinion its a real alternative to bow thrusters and reliefs stress while maneuvering in crowded marinas. under sail its less spectacular, but gives some additional options for sharp turns. A diy design seems feasible, but would require a well designed layout for the rudder / flap combination as well as appropriate mechanical layout of the lever-construction inducing the flap action. also use of tiller pilots may require additional attention.