Skeg or not?

[robmurray]

Many people seem to be of the view that a boat is not safe for blue water without either a skeg or a long keel. And yet many new "blue water" cruisers, for example some Scandinavian makes, now have balanced rudders. Would you trust a boat without a skeg?

 

[oldsaltoz]

Many people seem to be of the view that a boat is not safe for blue water without either a skeg or a long keel. And yet many new "blue water" cruisers, for example some Scandinavian makes, now have balanced rudders. Would you trust a boat without a skeg?

If the ruder is skeg mounted it should never be a problem, have had 2 with arrangement, some engineering required to get any balance on the leading end though.

Spade rudders (No Skeg) are almost always built with 10 to 12% balance, however they are more exposed and perhaps less support.

If you prefer tiller steering then a spade has great feel and needs less effort.

Avagoodweekend......

 

[Tranona]

Yes. Your use of the word "trust" implies belief rather than rational thought.

Things have moved on since the early days of spade rudders using small section stocks and inadequate bearings - often with rudder frame construction that used a mixture of metals and poorly made grp/foam blades. If you want an example there is a 1970's very well regarded boat in our club that ran aground and the state of the rudder is enough to make the designer/builder hang his/their head in shame.

However standards of design and manufacture are much higher now, and as you say, many of the long term "skeg hung" builders are now using them. Perhaps you should address your question to them.

There are of course characteristics of long keel and skeg hung rudders that people like, but it seems that not many buy new boats! BTW I own two boats. One has a long keel and "traditional" rudder (built by myself so bullet proof) and the other a mass produced modern cruiser with a spade rudder. Both seem perefectly satisfactory to me.

 

[vyv_cox]

Many people seem to be of the view that a boat is not safe for blue water without either a skeg or a long keel. And yet many new "blue water" cruisers, for example some Scandinavian makes, now have balanced rudders. Would you trust a boat without a skeg?

I've never owned a boat with a spade rudder, so can only speak from acquired knowledge, which some might call prejudice.

1. A very high profile mishap on the ARC which led to scuttling of a new, expensive boat was due to loss of the spade rudder. Another one a couple of years earlier, when an accompanying ship knocked up a replacement from a scaffolding pole and some bits and pieces, also led to scuttling, AFAIR.

2. There is a greater tendency for fouled ropes to become wedged between hull and rudder. A skeg tends to guide the rope away from this area.

 

[Robin]

I've never owned a boat with a spade rudder, so can only speak from acquired knowledge, which some might call prejudice.

1. A very high profile mishap on the ARC which led to scuttling of a new, expensive boat was due to loss of the spade rudder. Another one a couple of years earlier, when an accompanying ship knocked up a replacement from a scaffolding pole and some bits and pieces, also led to scuttling, AFAIR.

2. There is a greater tendency for fouled ropes to become wedged between hull and rudder. A skeg tends to guide the rope away from this area.

But then I remember a certain one time YBW magazine editor in his Sadler 34 retiring from the ARC with a damaged and leaking skeg!

There was also a serious incident a long time ago I believe of an older Moody which sank off Australia as a result of skeg damage as the skeg was moulded in to the hull rather than it being a separate moulding added to the hull. The owner was advertising for others with similar problems to contact him, presumably for some kind of 'class action'.

We have a half skeg on our current boat as also on our last boat. It gives some extra support I suppose whilst allowing some area of rudder balance, although it does leave a gap for ropes to get trapped between it and the rudder.

 

[jimbaerselman]

Many people seem to be of the view that a boat is not safe for blue water without either a skeg or a long keel. And yet many new "blue water" cruisers, for example some Scandinavian makes, now have balanced rudders. Would you trust a boat without a skeg?

There are three issues here.

The strength issue 'would I trust' is solely a matter of correct engineering design and build. There have been errors in the past; lessons have been learnt; currently built boats should be fine. But how do you know when (or if) your builder/designer learnt the lessons. And how do you know that similar design/build faults don't limit the life of your skeg hung rudder (badly aligned bearings . . .). Destruction testing isn't really an option!

Then there is a handling issue. A skeg provides rotational damping which is not present with a spade rudder. That means that the boat has greater resistance to a spinning/yawing moment. Two effects - it's less easy to spin the boat if you want to, and more easy to resist disturbances when waves try to spin the boat. Nice for straight steering, not so hot for tight harbour manoevring.

The 'picking stuff up' issue remains. Spade rudders trap ropes more easily, and if there isn't provision to keep the gap between rudder and hull closed, will jam up quite nicely. So, how likely are you to be sailing in waters where loose ropes will be lying round - or sheets hanging over the side?

No easy answers, eh?

 

[KellysEye]

Personally I wouldn't go blue water sailing with a spade rudder, it's too exposed, although many do. As an aside, I have the same view about swept back spreaders and also no back stay. I don't like keel bolts either.

Spend long enough at sea and I think it's prudent to assume that at some time you will have heavy weather, hit something or be hit by something. We've had two of the three.

 

[Tranona]

I've never owned a boat with a spade rudder, so can only speak from acquired knowledge, which some might call prejudice.

1. A very high profile mishap on the ARC which led to scuttling of a new, expensive boat was due to loss of the spade rudder. Another one a couple of years earlier, when an accompanying ship knocked up a replacement from a scaffolding pole and some bits and pieces, also led to scuttling, AFAIR.

2. There is a greater tendency for fouled ropes to become wedged between hull and rudder. A skeg tends to guide the rope away from this area.

In both cases it was not the rudder that failed but the GRP stock. Further down this forum you will find a long thread on the failures of this kind of stock on this make of boat. There is no reliable record of similar failures of aluminium of stainless stocks. The builder responsible for the GRP stocks (of which it admits about 20 have failed) now uses stainless. Failures have also been recorded where carbon fibre has been used, mainly on extreme racing boats. A number of performance mass production boats use carbon fibre but do not seem to fail. There is a useful discussion on rudder design and construction in the MCIB report of the Hanse that sank in the Irish Sea a few years ago.

As to getting ropes caught, this is also true of the popular semi skeg designs where there is a similar gap around the lower bearing, arguably more vulnerable lower down. Full keel hung rudders can also cause problems of a different kind as I know to my cost when the piece of net not only stopped the engine, but filled the aperture and seriously restricted rudder movement and therefore control.

The "bluewater" resistance to spade rudders is probably based as much on "it does not look right" rather than any serious analysis of relative strength. Just about all major designers, many of whom have in the past designed boats with skegs now use spade rudders, and as noted by the OP bastions of the "bullet proof" cruiser builders now use them. This suggests that the upside of lighter helms, greater control, lighter weight etc outweigh the perceived downsides! The proof is in the number of spade rudder boats that make successful ocean passages.

 

[whipper_snapper]

I once sailed a cat with spade rudders. Twice within 1 week we hooked a net at night and came to a shuddering halt. We spent ages in pretty difficult conditions trying to unhook the net but on both occasions we had to cut it free. We really did not want to do that because it represented a fisherman livelihood but we had no choice.

I would not want to go far in a boat that could hook a rope and jam it solid, and then leave you being blown off with the full weight of the boat on the rudder shaft. That is especially true in shallow coastal water where nets are most likely.

More conventional boats would have sailed right over the nets without issues.

 

[Tranona]

There was also a serious incident a long time ago I believe of an older Moody which sank off Australia as a result of skeg damage as the skeg was moulded in to the hull rather than it being a separate moulding added to the hull. The owner was advertising for others with similar problems to contact him, presumably for some kind of 'class action'.

Glad you brought that one up. I avoid criticising "proper" boats like Moodys now as I usually get a hard time from the "proper" boat people!

However, one has to remember that the Primrose Moodys were way ahead of their time when they were designed - and one of the early fin and skeg designs drawing on his eperience of racing yachts. Angus was confident enough to go bluewater himself in one. However, the light displacement (and light build) was considered by many at the time as not seaworthy. It was true of the skegs - they broke away and all the ones I looked at when I was seriously looking to buy one had re-inforced skegs. The keel castings were also on the thin side and poorly fastened so some also had twisted keels. As for the mild steel tanks, awful electrics and steering prone to seizing and osmosis etc...! Still they have a lot of very good points and if sorted are excellent value for money.

 

[Moscowman100]

Not expert so correct me - I thought the main issue with spade rudders was that, being free in the water, that they could be designed like an aircraft wing to create 'lift' making them smaller, with less wetted area etc and therefore ideal for racing.
Barn door rudders, with the skeg providing turbulence, have to be larger to achieve the same effect as they cannot produce 'lift'.
For offshore use, the main issue for me is that a spade rudder needs a certain minimum speed to avoid 'stalling', which makes heaving to etc problematical. From a design perspective, a skeg eliminates some severe stress points at the bearings of a spade. For sure, good spade rudders can be built, but at a price which I suspect some builders try to minimize.

 

[Tranona]

As with many developments which start off in racing, they migrate to cruising boats. You are right about spade rudders being more efficient foils and like fin keels need flow to make them work. I have had no problems heaving to in ordinary conditions with my spade, but have not been out in heavy weather so no idea how the boat heaves to in those conditions. In "normal" sailing the helm is light and well balanced and I have no problems balancing the boat to sail herself. One clear downside is that such rudders tend to lose grip as the boat heels, especially when attached to a fat hull form - not helped by many being narrower at the bottom than the top.

As to robustness the newer large diameter stocks in big bearings supported by strong hull structure seem adequate compared with the small diameter solid stocks used in earlier designs. Not sure about actual blade strength as have not seen any examples of blades breaking (although no doubt there have been some). Stock strength does seem to be an issue given the well known failings of composite (mainly GRP) stocks. Also the Hanse that sank did so because the failure was above the upper bearing and seal, but below the waterline, allowing the whole assembly to fall out. There was not an above waterline bulkhead to prevent the water from flooding the boat.

 

[Conachair]

Not sure about the "trust" aspect but I wouldn´t have one. Too many stories about fouled fishing nets/ropes. I have long keel and transom hung rudder and know of at least twice where I´ve ran over a mass floating nets or spagetti of old big ropes. And god knows how many times without knowing about it. Spade may not get caught up but too exposed for me.

 

[Tranona]

Not sure about the "trust" aspect but I wouldn´t have one. Too many stories about fouled fishing nets/ropes. I have long keel and transom hung rudder and know of at least twice where I´ve ran over a mass floating nets or spagetti of old big ropes. And god knows how many times without knowing about it. Spade may not get caught up but too exposed for me.

Like many things, I think the rope snagging is over hyped. Not sure there is much difference in propensity to snag nets with a spade rather than a skeg - unless you have a bar or wire from the back of the keel to the skeg. I had the rather unpleasant experience of listening to the coastguard exchanges in an incident off Old Harry when a skeg caught on a lobster pot line and tethered the boat in a 3 knot tide over wind. Skipper foolishly went over the side and was killed by the stern coming down on his head. He was tethered to the boat. Heard his wife calling the cavalry and watched the helicopter land in the park with the (dead) casualty.

I have snagged nets off the Greek mainland - placed there not to catch fish because there aren't any but because they qualify for an EU subsidy. No problem with a spade rudder because it is just under the transom rather than buried right under the boat. Stand on the sugar scoop and push the net down with a boat hook untiol clear.

Rope cutter on the saildrive also helps, although mainly there to chop up plastic bags.

 

[Conachair]

Like many things, I think the rope snagging is over hyped.

Have to disagree there. I´ve met them, it happens and when it does you´re on your own. This morning met up with some friends who picked up a pot recently off Brazil. He´s over the side in 10´swell with waves breaking over the stern and his wife is shouting when the bigger waves come in so he can keep clear. All good in the end thankfully. Plenty other stories doing the rounds as well, though most seem to get off, few boats lost, but blue water you are on your own, no one is coming to help. Not overhype, very dangerous.

 

[Tranona]

Not overhype, very dangerous.

Not disagreeing that it can be dangerous - see my account of a death as a direct result of this kind of incident.

However, it is not just spade rudders that are vulnerable, so are skeg supported rudders, particularly partial skeg. The "overhype" observation is partly based on the sheer numbers of spade rudders in use, compared with the number of incidents. I also operate in a section of the marine trade where I hear lots of "stories" about the effect of debris in the sea on yachts. Long keel with attached rudder is less vulnerable to ropes and nets. However, as I recounted from my own personal experience the consequences of picking up (in my case a piece of net about 60cm square) can be a loss of steerage way as it fills the aperture.

Clearly there are steps one can take to minimise the impact of stray rope and nets, none of which is totally foolproof. For obvious reasons the propeller is the most vulnerable bit of underwater equipment and can be protected. Rudders are vulnerable, but the shape of many means that there is a chance the boat will ride over debris. The distance between the back of the keel and the rudder also has an effect. The worst situation in my view is small mesh net strung from buoys just below the surface. More common in shallow waters for obvious reasons. Difficult to see in daylight, impossible at night.

So, nothing is foolproof, and I am not trying to ignore the dangers, but the thread is about styles of rudders, particularly skeg hung vs spade and I am not sure that there is much difference between the two in relation to catching ropes and nets - both are vulnerable and more vulnerable than keel hung rudders

 

[saltwater_gypsy]

Never heard of a skeg hung rudder dropping off.
On the Seastream I have a 6mm wire between the skeg and the keel which successfully diverts lobster pot lines, nets etc. (I think some Vancouvers have the same arrangement)

 

[Tranona]

Actually Vancouvers have a solid bar. As you no doubt saw the arrangement you have is one I suggested earlier - useful but not foolproof. As to spade rudders falling off, once you take out the Hunter failures and the odd racing boat failure, there is not a lot of evidence it is common. The Hanse failure referred to above was a one-off and the thorough investigation failed to find another example of failure for comparison.

However, I am sure there are examples of spade rudders failing in some way, just as there are examples of skeg hung rudders - and indeed "traditional" attached keel rudders - failing. Just that the "evidence" is in the story books and not well documented.

 

[jimbaerselman]

Never heard of a skeg hung rudder dropping off.
On the Seastream I have a 6mm wire between the skeg and the keel which successfully diverts lobster pot lines, nets etc. (I think some Vancouvers have the same arrangement)

If you have a wire, plan for what may happen if it is broken. Ensure it has a weak link, positioned so that it is impossible for either end of the wire to wrap around your prop shaft.

 

[robmurray]

Thanks guys - some great points made. As with so many things in sailing it is difficult to take a single issue of boat design in isolation. Where I am at is that the best boat to go long term sailing in is the one you have - ie the one you know how to repair, handle, etc. In my case that means spade rudder (X Yacht). Interestingly, my previous boat (Starlight 39) was a semi skeg and that is the only boat that I have got caught on a pot - rope trapped between rudder and hull. Thankfully in the Solent but, embarassingly, led to my only ever lifeboat rescue!

I guess there is a broader observation for me. Many of the older boats that now would be thought of as great sea boats were, in their day, actually high performance boats. My own X412 will no doubt lead to lots of posts telling me how unsuitable she is for cruising but as she gracefully ages the modern blue water boats are looking more and more like her...

It does make you wonder whether in 20 years time a typical liveaboard will be rowing away admiring his Open 50...

Happy sailing