H30 replacing skeg with spade rudder

[keelboatguy]

Hello, I have taken my '81 H30 skeg apart due to delamination. I have previously read about a gentleman that used a H37 spade rudder design and permanently replaced his skeg.
Can someone point me in the right direction, any information is truly appreciated.. Thank you

 

[DianaOfBurlington]

I can imagine one reason why you would want to do this; but in terms of general seaworthiness the rudder is better with a skeg on it.

I am considering replacing my H25's modified-spade rudder with a skeg for strength and safety reasons.

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[Nereussailor]

Why?

 

[keelboatguy]

The reversing characteristics of the 74-83 hunter is very poor, major prop walk. I sail mostly solo (read non sailors) and want more maneuverability for the tighter marinas/harbours. As mentioned I have my skeg apart, and find this my opportunity to 'check out' my options.
There was a previous poster, Steve Fredrick, that removed his skeg and replaced his rudder with a H37 design. He reported that his prop walk was basically eliminated.
I am a lake/bay sailor so snags like lobster pots and the like are not an issue.
The H30 is the only hunter designed with a skeg. My research has shown that the Hunter 'typical' rudder has the same bearings structure whether a skeg or spade.

 

[JK_Boston_Catalina310]

I like the idea but can't offer any help.

I did want to address the previous post about spades not being seaworthy. Look at modern designs, most now have spade rudders. This includes "blue water" boats. Do some research on rudder failures and show us any links where spades have failed and the cause isn't poor maintenance (I.e. Delamination, failed bearings that are original, etc.) as opposed to being caused by hitting something. Most people with a failed rudder will report one load bang, not a series of bangs like you would expect if something floating hit the hull multiple times on the way to the rudder indicating that many rudder failures are likely falsely reported as caused by hitting an object.

Next look at the efficiency of rudders based on hydrodynamic principles. Spades are more efficient and take less stress while being used. This is why they are made from thinner wallled tubes instead of solid rod. It's not that they are weaker, they don't have the same stress load so they don't need to be over built.

Finally, do some googling on spade rudders and boat designers. You will find several that admit to only using skegs and partial skegs due to public perception. In other words, the people who buy the boats influence that design not the realities of safety, strength or efficiency.

Good luck with the project and fair winds,

Jesse

 

[DianaOfBurlington]

Pro: skeg

For slow-speed maneuvering, especially in reverse, the spade rudder has much to commend it. It reacts fast and 'with authority', as my dad would say. For sailing (when the actual underbody of the boat is doing the leading and propelling), the two-plane 'bent' aspect of a rudder hung on a skeg behaves more tamely, creating its own Bernoulli effect and encouraging a curved path (like having steerable back wheels on a car, or like all-wheel pivoting on a railroad car). By the same token a single-plane skeg-hung rudder can be very skittery if allowed to get a little too far out of bounds (wear an athletic supporter if you have a tiller!). And Rousmaniere, Stephens, Chichester and others have commented on the almost unbearable awkwardness of a spade rudder in strong following seas or generally rugged weather.

Also (and speaking as one who just recently repaired one, post-Sandy), the skeg-hung rudder is much stronger and provides some sacrificial or defensive material (the skeg) in the event of surfing through an inlet and whacking the rudder on God-knows-what under there. I actually substantially stiffened my spade rudder's rudder post sleeve inside the lazarette and added a short bulkhead damming off that space from the rest of the bilge, in the (however unlikely but entirely possible) event of the rudder shaft's ripping aft into the hull skin. As it is now, I have at least a fighting chance if I hit the rudder fin on something. It's an old-boat fix I would recommend to anyone cruising where you can't walk ashore or get help in 20 minutes.

In response to Jesse's post, spade rudders are under phenomenal stress-- the whole blade, cantilevered out there, takes 100% of it with no help. The fact that 'most boats have them these days' is because they are cheaper to build (and repair), not 'better' technically or structurally. That's also the reason the rudders (like the whole boats) are lighter in construction as well. When our 1970s Hunters were designed and built, there was at least a mindset that boats were to be used for sailing in deep water in yet-unknown conditions. The Hunters of the 1990s and 2000s were designed and built with (what was assumed to be) a conviction that 'most' people don't sail like that any more, that most sailing is done by the day, between safe anchorages at night, and in predictably mild conditions and with plenty of electronic and mechanical assistance.

I'm only suggesting a technical or theoretical position here. What happens in the 'real world' may be entirely coincidental to what is, technically, compromised logic. Maybe I'm just the Dilbert here (!) but I'd prefer to be a little pessimistic rather than optimistic when it comes to working on people's boats, giving them advice or sailing myself. I get the rep of being 'Doctor Doom' on here; but it's true what I have long said: 'Prudent pessimism is the mark of a responsible skipper.'

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[Dalliance]

KeelBoatGuy,

While a spade rudder may be more nimble in close quarters than a skeg mounted rudder, no type of rudder is effective against prop walk until you have sufficient way-on. How much prop walk you have in reverse at slow speed is dependent on the type of prop you have, not the rudder design. If your aim in getting rid of the skeg is to reduce prop walk, I think you may be disappointed.

As DianaOfBurlington said, the skeg mounted rudder is a stronger design, with unique handling attributes under sail. Mr. Cherubini designed these boats that way for a reason and changing the design could result in unintended consequences. I believe you should repair and reinstall your delaminated skeg.

You're in Ontario, so you still have time before sailing season. Grind off the delaminated fiberglass, dry out the wood core indoors for 2 or 3 months (near a radiator or fan helps) and re-glass it. Then stick it back on with 5200 and stainless bolts as it was designed. It seems counterintuitive, but do not glass over the joint. See DianaOfBurlington's post about this dated 5/21/13.

The P.O. of my '82 H30 made that mistake and I repeated it once. It leads to a annual problem of water seeping in behind the fiberglass at the rudder post where you can't cover the joint, then freezing and splitting the glass at the lower end of the joint during the winter.

 

[keelboatguy]

The skeg on my H30 has a closed cell foam core, it has been removed with only the stainless frame remaining. The only requirement for the radiator would be for my warmth during the Canadian winter.
If you compare the typical Hunter rudder system design to the H37 rudder design then to my H30 rudder system the only difference is the H30 has a skeg/rudder the other a spade rudder, same bearing/post/thru hull design. I'm unclear as to why one system would leak and the others not. In reality you can remove the rudder in water at the dock without leakage. I would choose a calm day.
I do agree you require way-on to maneuver in reverse, and all my boats have had prop walk, however not as severe as the H30 (my smallest boat, creaping age syndrome).
The debate goes on as to which prop style is best at reducing prop walk, Mr Cherubini designed it with it's current propeller.
I do have lots of time to research and come to a decision, as the skeg skeleton is still on the boat.
As forementioned, I appreciate any info in the skeg/spade debate.

Thank you

 

[Dalliance]

Interesting. If we both have the original skeg on our boats, then Hunter changed the skeg construction from a closed cell foam core with stainless steel frame in '81 to a solid wood core in '82. I wonder why. Could you please post a photo of it for information purposes? It might help someone in the future.

Keep us posted on whatever you decide to do. We'll be interested to see how it turns out.

 

[keelboatguy]

 

[kito]

Someone correct me if I am wrong but I was thinking that on the H30 the shaft is offset a bit so to clear the skeg for removal. Could add to some of the prop walk issues on the H30.

 

[Dalliance]

There is no offset of the prop on the Cherubini H30. You would either have to remove the skeg to pull the prop shaft out or remove the engine and pull the prop shaft from inside. It's debatable which is more work.

 

[keelboatguy]

I changed my cutlass bearing a few years ago, and if, you can get the coupling and prop off, there is enough flex in the shaft that you can scrape by.
If not the removal of the shaft mount, would be easier than pulling engines and skegs, it would also would quarantee flexibility around the skeg.
Just so you know...I cut my shaft out

 

[DianaOfBurlington]

Don't fix the core.

After much procrastination I borrowed a moisture meter from a neighboring boat owner and checked my hull. I really had been dreading this, you know. But the hull was fine-- it was the rudder blade that banged the stops on the meter. Upon closer inspection I found all the seams between the two halves had been open -- they had blue bottom paint in them all the way through. (POs--! :naughty: )

I used the Dremel and v-ed these all out, applied epoxy filler, and then 'glassed the edges with tape, using epoxy. I never got anything from any of the weep-holes I made in the blade, both in the sides and along the bottom. I even applied the vacuum-cleaner hose to them: nothing. But it was pretty clear it'd had water in it and the foam core is probably shot. I concluded that the water had leaked in around the post in the top, which is properly sealed with 5200. I filled that gap with epoxy and 'glass (by way of 'glassing the seams) and then routed it out with the Dremel to accept a bead of 5200. Right now I owe it some tape across the bottom which will seal up the last of the seams, and then I'll put on barrier coat and call it done.

At Cherubini we found that most of our foam-cored C44 rudder blades have gone rotten with the years. One of my conclusions was that people keep removing the cute teak fiddle on the top and taking it home in the winters to revarnish it (it should be painted as part of the boot stripe); and, when it got reinstalled with less than 5200 and/or mishmash, it was working back and forth and water was getting in through the mounting holes. That rudder is very stoutly made, the rudder pipe is phenomenally strong, and we concluded the foam core serves no purpose whatsover, so it's been omitted completely from newer and repaired boats.

I don't know about the foam core in my rudder and I don't care. The original 'glass was pretty flimsy but it's now stiffened with new 'glass, extending 3-6" from the edges (it's a small blade). I am making no effort whatsoever to restore the foam inside it. I thought about cutting a hole in top and filling it with new foam; but after drilling a few holes I found it would not even accept a syringe's worth of epoxy. So in one of my weep-holes I will install a bronze drain plug.

I recommend the drain plug for everyone's rudder. Take out the plug every haul-out; and if the boat will not be out of the water for more than a few weeks, apply a hair dryer or dehumidifier under it for a few hours and see if you get any sweat weeping out of it. Use epoxy on the threads when putting it back in. (Never have faith in silicone for this.) If you have any difficulty threading it out again, touch it with the tip of a soldering-gun for about 15 seconds and then turn it out with a wrench.

It was a tough pill to swallow to admit that all our C44 rudders get water in them (the C48s don't have the wooden thing on top and the boats are newer, so we haven't seen it with them). But it's futile to worry about it. Your best 'permanent fix' is to reinforce the 'glass skin itself and to provide the drain plug. Removing the plug and letting it dry each season will offer the SS pipe and welds inside a slightly-better chance at longevity. But, in short, I'd worry more about the metal bits inside than I would about the core-- and I certainly would not expend the time and energy to replace the core for its own sake.

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[DianaOfBurlington]

Just so you know...I cut my shaft out

How'd you get the new shaft back in?

 

[keelboatguy]

I had to replace my cutlass bearing as mentioned. I also removed and rebed

 

[keelboatguy]

...sorry big fingers... I also rebed my prop shaft strut at that time which gave me plenty of lateral movement.

 

[uncledom]

I'm not sure of the rules on name dropping here, but I just changed my prop on my 41 and have virtually eliminated walk in both forward and especially in reverse. This prop also improved motoring and motor sailing. It was a bit of money but no real work, just a prop change.

 

[maxinterlude]

Hello guys , I just lost my spade rudder near Caicos Islands . The boat will be haul out tomorrow .If someone could help me with the specs of the rudder of an Ontario 32 1978 , I would really appreciate .

 

[kito]

To get my shaft out on my H30, I just ground a groove into the side of my skeg to slide the shaft out. That was before I seen my strut was cracked and needed to be replaced so the strut had to be removed anyway. The groove wasn't needed. The groove will be filled with epoxy and painted....no big deal.