Trimaran “Buddy” abandoned north of Bermuda

[oldsurfer]

^^^^^^

 

[Russell Brown]

I know, Oldsurfer. A kick-up rudder in a case works on small and big boats alike. If it's pulled down with a string (like that familiar one in the photo), it can just be pulled back down after you hit something.
I like the thread drift because I'm learning things about rudders, but it's funny how far we have come from the thread topic...

 

[Russell Brown]

Well…nobody uses a transom hung rudder at sea …for a dozen reasons

and that home made stuff..is well…homemade..I’m not impressed

Dude, There's nothing crazier than a shaft-hung rudder that can break off, bend over, tear a big hole in the bottom of the boat, etc.. You need to look around.
You dissing home made? Lots of home built boats of much higher quality than production boats. Stop being such a know-it-all snob. There.

 

[SolGato]

Someone check the rudder on this thread, I suspect it kicked up a few pages ago and we are drifting off course 😂

I’m partly guilty, but I think it was decided that we are probably unlikely to learn what exactly happened to Buddy, however the news of the event has many of us agreeing that the potential for damage from a strike and the need to design and plan for it is important.

Big or small vessel, ocean or lake, the potential for a ruined day, or worse the total loss of a vessel or a life is a concern shared by all.

These hazard and design challenge issues aren not new, but seem to be ever increasing for a number of reasons, and discussing possible ideas and solutions while studying and sharing experiences and examples of solutions from the past is a helpful exercise and a worthy drift IMO.

On that note, and to bring a little innovation and tech into the design challenge, Russell have you seen the new electronic remote steering controls for outboard motors? Thinking about these in relation to your proposed rudder design challenge.

They are quite compact and built to withstand a marine environment, and I wonder if one could be used in place of a traditional quadrant and cable steering setup in conjunction with a self contained plug type kick-up rudder box.

With the unit mounted atop a rudder shaft housing, the whole assembly in theory could easily be swung up and over until vertical since the only connection point would be the pivot point and a wiring harness, so there would be no worry of fouling of steering cables, etc..

What I’m not so sure about is if they even provide enough steerage lock to lock for a rudder application.

Personally I’m not a big fan of steering wheels on sailing vessels, but it could be an interesting way to create a compact easily articulating self contained remote steering system.

 

[bushsailor]

Yes Kick up rudders of good design are essential.
The ideal would be mini keels(plus daggerboards if a cruiser really wants to sail around the world the wrong way), kick up rudders, shaft drive and racked bows.
Then when cruising a strike will not create a major problem.

 

[Ravenswing]

Well…nobody uses a transom hung rudder at sea …for a dozen reasons

and that home made stuff..is well…homemade..I’m not impressed

What the hell, slug zitski??? How do you know my home-made crappy transom hung rudder isn’t up to the task of the past 5,000 miles at sea? You wanna come inspect the engineer-specified 20 layers of carbon & glass built into the cassette? Do you actually sail multihulls on the ocean?
… I’m not impressed by lack of experience typing

 

[he b gb]

I say ‘let the thread drift’, there hasn’t been this much interesting discussion on MA for a long time! (except for that slug guy)

 

[boardhead]

Certainly did take off on a tangent - meanwhile Buddy drifts off to the northeast taking the evidence of the cause of her demise with her while we keep guessing.

 

[boardhead]

There's Buddy! Mini keel with kick up centerboard buried in it and is that a spade rudder?

 

[harryproa]

Based on my experience with kick up rudders, not yet.

I am not sure how you ever argue that this is lighter or easier to build however than glassing a rudder tube inside the hull.

I posted my arguments why installing a rudder is more than "glassing a tube into the hull" Address these rather than the examples you show which are neither ideal, nor particularly easy to build.

The requirements for a successful kick up rudder are that it be fully supported until it is well clear of the water and that the kick up happens even when the rudder is at an angle to the flow. It is handy if it can be pulled down easily and remotely. These are not difficult to achieve.

(and how does steering work with one blade kicked up? It's not trivial)

Steering is much easier with one rudder kicked up than it is with one bent and jammed.

And with regards to boards, I'm somewhat ambivalent. I accept that they may be damaged by floating debris and require replacement or repair at some point. If I hit a centerboard with a big log I expect somewhat less damage but still some. (because a centerboard still has mass and it takes time for it swing up out of the way if you hit something; even more so at high speeds)

However with a daggerboard there is a very good chance I can just hoist it on deck and repair. With a centerboard it's probably a haulout or at least a series of swims. (often the pivot pin is underwater or too close to the waterline to safely get the pin out in the water). Then you have to drop the board while the boat is in the slings, and replace it the same way (not enough clearance under the boat to easily remove when blocked)

We are not talking about tapping a 4 x 2 at 5 knots, but running into a log, container or big animal at 15+ knots. The daggerboard (or it's remains) will not be easily removed (see Spindler's experience at 5 knots). And more critically, if it hasn't broken, the boat will have gone from fast to stopped in a very short time. People will be injured. If it has broken, you can probably say goodbye to the saildrive and perhaps the rudders.

Centerboards with big slots in the bottom are more draggy, even with mylar flaps. And they can mess up interior spaces something serious. I could likely live with this.

There are much better ways to fil the slots than covering them with mylar. It is trivial (and a safety requirement) to include a dam around the pin (and any other holes in the hull) to make it removable without sinking the boat. If internal space and slot drag are issues, it is easier and lighter to support the board under the bridge deck than it is to support the mast.

Find me a fast production cat that has successfully implemented centerboards and kick up rudders.

Your faith in production builders is touching. There are several home builders who have done so. For me, the question that should be asked is "Find me one that can hit something solid at 20 knots without injuring anyone or damaging the boat so it requires major repairs."

Rob - what has your experience been at sea when a rudder/board has kicked up? No problem with getting them down again? Have they experienced any damage from collisions with logs or the like?

I've broken 4 (2 impacts, 2 unsures) rudders offshore, racing and cruising in cats and monos, and plenty more during the Harryproa development. I have hit a whale, several rocks, sand bars and sundry floating objects. Apart from the whale (which loosened keel bolts on my first Sydney Hobart boat, 48 years ago), none were at double figure speeds.
When we started selling plans, I could not live with the inherent safety issues with shafted rudders. Hence, the boats had to have no holes below the water, kick up, liftable (for safety in storms, shallow water sailing and sitting on the beach) rudders, which were large enough to act as boards as well. The current crop work well.
Getting them down when kicked up is easier if they are in cassettes, as long as they are supported for the full range of travel. A couple of Harryproas have opted for fixed rudders and/or daggerboards. They have had to be slipped for repairs at some stage. The kick up rudder boats, not so much.

Bushsailor,
I meant to ask. What was the upwind result of moving your boards forward?

The other big minus not really mentioned here (at least from my point of view) is that most kick up rudder systems that I have seen so far tend to ruin the transom, steps, and swim platform on a catamaran even in the down sailing position - which to me is a real negative as this aft area of the boat is really important for live aboard life and needs to be well designed to serve a number of purposes, instead of being blocked by rudder mechanics.

The transom and steps clutter issue is a real one, unlike some of the others mentioned. If you ever do decide to install a kick up rudder (hopefully a decision made before your fixed one hits something at 10+ knots or you are washed sideways onto a beach), send some pics and start a discussion about solutions.

 

[salt.ed]

I really like the simplicity Mike Lenemen used on Minette... I made a drive recently to LA to check out and get ideas for my own kick up rudder build on my Polycon. Casing is wood core composite. Rudder is wood and and high density foam core and glass. (built in early 80s so he didn't recall exact details).

Minette is a very fast concept 40 with great race record and the rudders seem to have held up well. They are balanced nicely so they push down into place fairly easily despite being buoyant.
They are held in place with a SS pin across the aft. He told me he used chopsticks for pins when sailing in shallow water in Bahamas so they would release easy with any bottom contact.