Should boat manufacturers start making sacrificial rudders?

[LittleSister]

The problem with a sacrificial rudder, especially of the spade format, is the rudder can be subject to huge forces in normal use. I find it hard to imagine that a rudder that would detach when hit by an orca would confidently stay attached when you're resisting a broach as you surf down the front of a swell.

 

[14K478]

I’m a little surprised that nobody questions the. condition of the average boat’s GRP rudder. I bet most of them are “wet” and that the remaining strength is much less than it was when new.

 

[RunAgroundHard]

I think at best it could be an option but I don’t really think it is justified. It just becomes an overhead that needs to be reflected in the price that maybe folks dont want to pay for.

 

[Sandy]

Provide them with something to focus on and attack other than the rudder. Tow a series drogue of FB meat pies or something.

I think even whales would turn their noses up at a FB pie as they have almost no meat in them.

 

[rogerthebodger]

I’m a little surprised that nobody questions the. condition of the average boat’s GRP rudder. I bet most of them are “wet” and that the remaining strength is much less than it was when new.

Especially when you look at all the GRP rudder rebuilds and the crevice corrosion at the tang rudder shaft connection

 

[Iliade]

Looking at the hull damage in post #1 I think one can safely say that the rudder was pretty securely attached to the rest of the boat.

Maybe a bigger version of these on the rudder sides?
Defender Seagull Spikes

Or 'just' remove the rudder for the dubious passage and fit a transom-mounted lifting one. Preferably steel and electrified...

Or a shark cage for the rudder. Might keep some of the pot lines off too if you're lucky.

Or, fit a weak sacrificial rudder, made of something tasty but filled with syrup of figs and chillies.

 

[Baggywrinkle]

Looks like some level of sacrificial design is already the case ....


https://www.sailmagazine.com/diy/rudder-awareness

Problem is when it remains attached, the Orcas keep going trying to remove the appendage like the fins of larger prey .... resulting eventually in a hull breech. And if it's hung on a skeg, then that gives them a point to attack which is basically a strong lever acting directly on the hull laminate, and the longer the skeg, the more leverage they have.

Don't know what the answer is, stronger rudders may just prolong the attack and cause even more severe damage - another lesson learned in the car industry, a strong part of a structure can transfer the force elsewhere without any dissipation - so it just breaks somewhere else.

A normal person can still hold the wheel when a yacht is broaching or surfing, and still keep the rudder straight, and neither the rudder, nor the stock, nor the autopilot gets bent out of shape.

An Orca attack can rip off skegs, bend stocks, break wrists and fingers, and bend hydraulic autopilot rams on not insignificantly sized boats. Seems like that is an order of magnitude bigger than the normal forces acting on a rudder.

I think the aim is to retain hull integrity, while also preventing any water ingress from flooding the rest of the boat. If the Orcas are determined, and physically big enough, then it's pot luck if the rudder and or skeg survives intact IMO.

 

[noelex]

Sacrificial rudders are used by some boatbuilders, but they typically have a fracture point around 1/3 - 1/2 of the rudder length. The idea is that if the rudder strikes an object to lower portion will break away, but not damage other components and leave enough blade that the boat can be steered. This is not a great help with the current orca problem, as they would likely attack the remaining rudder blade.

I think for the Orca problem the best solution is a strong spade rudder, combined with very strong rudder bearings and hull reinforcement so if the rudder is ripped away there is no, or little damage to the hull structure. The lower rudder bearing should also be contained within a waterproof enclosure or a coffer dam. Ideally there should also be an emergency rudder.

 

[Neeves]

I recall that some catamarans have the rudders forward of the engine and sail drive (it looks most odd). I think the reasoning is to get the engine as far aft as possible and make 'better' use of the space (and get all the mechanicals away from the accomodation). Often access to the engine is from the transom steps. Catamaran rudders are smaller than monohulls (though whether that makes any difference regarding orca attacks is not in any way clear). But if the rudder or stock is in a water tight compartment then this will include the engines - or you need two water tight compartments (which might be no bad thing anyway).

Prop wash is obviously 'lost' with this arrangement but prop wash is irrelevant when you have 2 hulls - its decidedly easier to steer a multihull using 2 engines (and no rudder needed) than relying on prop wash.

On Josepheline we did not have sacrificial rudders but we did have sacrificial keels. The keels were built separately to the hull and compartmentalised, in our case 13 different spaces, but if hitting something hard enough the whole keel would peel of leaving the hull intact - or that was the theory (we never tested the reality). The keels drew more than the rudders - effectively the keel protected the rudders. The rudders were conventional, stainless stock with stainless tangs, foam and glass rudder blade. Later models had carbon stocks (I don't know what the tangs were).

Jonathan

 

[greeny]

Design boats with rudders on pintels on the transom (like the old days). Make them lift up like the smaller Jeaneau's, Beneteau's and dinghies. Carry a spare blade to replace if the orcas get you before you can raise it. If they do damage the rudder and mountings, the damage will be above the waterline so probably more manageable.

 

[rogerthebodger]

Design boats with rudders on pintels on the transom (like the old days). Make them lift up like the smaller Jeaneau's, Beneteau's and dinghies. Carry a spare blade to replace if the orcas get you before you can raise it. If they do damage the rudder and mountings, the damage will be above the waterline so probably more manageable.

That would be OK for tiller steered boats but not for us with wheel steering and a heavy rudder

 

[Daydream believer]

Provide them with something to focus on and attack other than the rudder. Tow a series drogue of FB meat pies or something.

Cannot do that. The spanish authorities have made it illegal to harm Orcas

Design boats with rudders on pintels on the transom (like the old days). Make them lift up like the smaller Jeaneau's, Beneteau's and dinghies. Carry a spare blade to replace if the orcas get you before you can raise it. If they do damage the rudder and mountings, the damage will be above the waterline so probably more manageable.

Considering the number of boats damaged by Orcas & the number of boats built since this phenominum started happening is it really such a big thing? Yachtsmen have already found ways to avoid the issue- My friends, for instance- have just done the ARC. To get south they stayed inside the 5M contour & made day sails in the areas of concern. Obviously they did not transit the Gib Straits which might need a different strategy. But even then one might ask what % of boats get attacked. Of course, even one is more than enough, if it is your own boat. But to redesign whole fleets seems a bit radical.

 

[greeny]

Cannot do that. The spanish authorities have made it illegal to harm Orcas

Considering the number of boats damaged by Orcas & the number of boats built since this phenominum started happening is it really such a big thing? Yachtsmen have already found ways to avoid the issue- My friends, for instance- have just done the ARC. To get south they stayed inside the 5M contour & made day sails in the areas of concern. Obviously they did not transit the Gib Straits which might need a different strategy. But even then one might ask what % of boats get attacked. Of course, even one is more than enough, if it is your own boat. But to redesign whole fleets seems a bit radical.

Doubt they stayed inside the 5m all the way through. Local wisdom is stay inside 20m. How did they get to the start line if they didn't cross near Gib?(joking-I think I know what you mean) I agree that the whole of the boatbuilding industry will not change its design philosophy. But individual sailors coming this way or locals sailing consistently in this area could alter their selection criteria for their next boat. I did. Lift rudder, lift keel, firecrackers and stay coastal inside 20m. Whenever I've seen orcas here it's been in excess of 40m depth when I've been out in the rib fishing. Not saying they never go shallow but reducing the risk is what it's all about. I'm being careful when sailing though because I really don't want to meet them in the sailing boat. Most of them are bigger than me.

 

[bitbaltic]

Hunter have been making sacrificial rudders for years.

Yeah every Hanse about 1998-2003 came with one. Ask me how I know this

 

[Daydream believer]

Yeah every Hanse about 1998-2003 came with one. Ask me how I know this

You mean one of these- But in all fairness- half of it was still there

 

[bluerm166]

Has anyone tried copious amounts of vegetable dye into the water ?