Skeg construction

[first wind]

Originally Posted by Stumble

In that case you need to hire a NA to design a new rudder and skeg. Figure you will need to remove 2 or 3 layers of glass within a foot or so of the new rudder post in order to bond the new skeg on, and likely reinforce the inside of the hull where the new skeg will be located.

The upside is you can likely go to a much thinner rudder post since the skeg will be carrying part of the load so you won't need the post to be as stiff.

that's some good info. thanks.

[Cheechako]

Most I've seen during construction were glassed in when the mold was layed up. But I have seen stripped boats where it was obvious they were "pasted on" to the hull.... maybe that was done during layup though. I've only seen hollow ones, although they sometimes are filled... often by the yard worker pouring left over catalyzed resin into the skeg!.
I like skeg rudders , but maybe it's overkill for that small Cal.

[Cheechako]

Originally Posted by goat

In the last 47 years of your boat's life, how often was the spade rudder lost? If the answer is zero, I'd look for other things to worry about.

goat

The answer is many. Bent, lost, etc.

[Jim Cate]

Originally Posted by Cheechako

The answer is many. Bent, lost, etc.

Cheech, Goat's question was directed at the specific Cal 27 that the OP owns,not all the boats in the world. His boat still has the original old rudder,still attached, still straight, still working ok.

My take on the situation is that if the OP isn't willing to trust his spade rudder, even after appropriate refurbishing of blade and post and bearings, then he should change boats, not attempt to change rudder design. The odds of him actually ending up with a stronger, longer lived and safer rudder are pretty slim IMO.

Jim

[Cheechako]

Originally Posted by Jim Cate

Cheech, Goat's question was directed at the specific Cal 27 that the OP owns,not all the boats in the world. His boat still has the original old rudder,still attached, still straight, still working ok.

My take on the situation is that if the OP isn't willing to trust his spade rudder, even after appropriate refurbishing of blade and post and bearings, then he should change boats, not attempt to change rudder design. The odds of him actually ending up with a stronger, longer lived and safer rudder are pretty slim IMO.

Jim

Yeah, I generally agree with that!.... at least within reasonable expense and effort! Not sure I'm willing to say, "it's 40 years old and hasn't broke yet so it should be fine" though. :>)

[donradcliffe]

I sailed on a Cal 28 which bent a rudder shaft, so all Cal boats must be suspect (we bent it back straight, and AFAIK it is still sailing).

I also know two boats which were abandoned due to rudder failure within 600 miles of completing their circumnavigations. One was a spade rudder, one was skeg hung. Lesson learned--Better to buy a boat with two rudders.

If you want to take your Cal 27 long distances short handed, your autopilots are a lot less likely to fail if you stick with the spade rudder.

[Adelie]

Looking at the weights for the boat, it has less non-ballast mass adjusted for length and beam than a J24. It is the 2nd most lightly built Cal.

Given that you are considering a skeg for the rudder, that implies some desire to go offshore. I would reconsider with that make & model. Understand that I am serious fan of Cal boats.

[first wind]

Originally Posted by donradcliffe

I sailed on a Cal 28 which bent a rudder shaft, so all Cal boats must be suspect (we bent it back straight, and AFAIK it is still sailing).

good anecdotal input!

Originally Posted by donradcliffe

If you want to take your Cal 27 long distances short handed, your autopilots are a lot less likely to fail if you stick with the spade rudder.

autopilots? as in electric autopilots? not for me. mechanical is far more reliable, steers better, and doesn't drain your batteries.

[first wind]

Originally Posted by Cheechako

Yeah, I generally agree with that!.... at least within reasonable expense and effort! Not sure I'm willing to say, "it's 40 years old and hasn't broke yet so it should be fine" though. :>)

well. within reasonable expense. i bought the boat for $300 off of the lean dock. it needs general TLC and maintenance but, is in sound shape and needs nothing seriously major.

not only do i intend to extensively cruise the bay (maybe farther, eventually) but, i intend to live aboard. i don't like the pop top. it has great visibility and is great for keeping it cool in the summer but, you can't sail with it up...even if you could it makes moving forward on deck difficult as the lid is wider than the actual opening in the deck. in the winter, it has to be kept down, so, you only have a hair over five feet of head room. i am not real tall but, would appreciate another 8". it also leaks cold air in the winter and, i would assume, it would leak water if enough splashed on deck. i am building a doghouse (plywood core fiberglass construction to match that of the deck)and am putting portholes around it to keep the visibility and ventilation. i got a great deal on 7 portholes from a scrapped out boat. an almand. just looking for an eighth porthole. three to a side and two up front. after i finish building it, i am going to glass it on. a bit of work but, worth it...in my opinion.

i doubt i will ever get another deal like that...and certainly not on a boat that is exactly as i want it (as if anything like that really exists).

i am anything but rich. and, at 47, i don't see me striking it rich and i'm not counting on moving up boat by boat til i hit the perfect one. in fact, unless something unexpected happens, this will probably be the boat i have til i check out of this motel. so, i'm going to do the best i can to make it into what i need it to be. some things can be changed. some can't. i'd love it to be a flush deck like the T2. more 'fun' room in the v-berth. but, that's not happening. i'd actually prefer a full keel. also not happening. (please don't let that statement be the spark that starts off the usual heated battle over keel types)

as far as this particular issue goes, i am collecting info. i already know i would prefer a protected rudder. no one is going to tell me that an unprotected rudder that is only attached to the boat through a pipe that runs through the hull and is designed to break before it rips a hole in the hull is safer than a protected rudder supported at the top and bottom and have me believe it.

heck, i'd actually prefer an outboard rudder with a skeg. but, that would move the rudder too far aft and affect the balance of the boat too much... not that i haven't considered it.

designing a rudder and skeg is also not a big problem. what i am trying to find out is the best way to construct and, especially, attach said appendage so that it is strong and does what i want.

am i doing that during this refit or at a later haul out? that really depends. but, i need to gather all the necessary information, draw up my complete plans, and then make my decisions based off all of that.

anyhow, i suppose i could go into debt for a boat exactly like i want but, the last thing i want to do, as i enter my life on the water, is drag a debt along with me. i'm trying to free my life of the BS of the 'normal' life on land and enjoy what life i have left sailing and living in an environment that lifts me up. i need to do that debt free and i'm not willing to let anymore of my life slip by while i try to save up 6000+ to buy the 'perfect' boat.

in an ideal world, i'd just sell this Cal (although there is a lot i really love about this boat) and go buy me a falmouth 34. also not happening.

we have a saying in the chopper community: chop what ya' got. in this case, sail what ya' got. too many people waste too much life waiting for the right time or the right boat. i don't have any left to waste. it's blowing by too fast as it is.

[first wind]

Originally Posted by Jim Cate

The odds of him actually ending up with a stronger, longer lived and safer rudder are pretty slim IMO.

Jim

the question i have for you is why? just the usual nay saying when someone thinks to attempt/do something outside of the norm or is there a valid reason that it's physically not possible?

not trying to be a wise acre. i have just heard that a lot over the years. you know, "that can't be done" or more usually "you can't do that" or "it'll never work". so far, those voices have all proven wrong. i've accomplished a lot of things that people told me i'd never be able to do.

however, if there is a real reason that this undertaking might be undoable, that's the kind of info i am looking for. it let's me know what i am up against.

[Stumble]

Originally Posted by first wind

the question i have for you is why? just the usual nay saying when someone thinks to attempt/do something outside of the norm or is there a valid reason that it's physically not possible?

not trying to be a wise acre. i have just heard that a lot over the years. you know, "that can't be done" or more usually "you can't do that" or "it'll never work". so far, those voices have all proven wrong. i've accomplished a lot of things that people told me i'd never be able to do.

however, if there is a real reason that this undertaking might be undoable, that's the kind of info i am looking for. it let's me know what i am up against.

You seem to be of the opinion that a skeg makes a rudder stronger. It doesn't. Wether skeg, or spade the strength is totally dependent on how strong it was designed then built to be. There is absolutly no engineering reason why a skeg is going to add strength to the rudder.

Note that I said 'designed and BUILT.' While there is no engineering reason to believe that a skeg is stronger on the design board, there are reasons to believe that skegs are highly subject to poor BUILT practice. They are hard to get right, because they are long thin foils and should be built as part of the hull not glued on afterwords.

So the reason why no one so far recommends doingthis is that in order to not end up with a rudder system that is more damage prone that what you have already first you need to run the calculations to figure out how strong the rudder you have now is. Second you need someone to design a new rudder that is stronger than what you have now. Since we currently have no reason to believe that what you have now is insufficient how much stronger is really academic. Does it need to be twice as strong, ten times as strong, youjustneed to decide how much stronger you feel it need some to be.

Finally after having it engineered you will need to build it. First you have to build the skeg and rudder of course, then you will need to find a way to attach the skeg to the hull. Ideallythis would have been done in the mold by building it out of the same structural glass as the hull. But that ship has sailed, so now you will need to remove glass from the hull I need order to strap the new skeg properly to it. Because just gluing the new skeg to the old hull won't do anything. You need lots of bonding surface to carry that much load, how much, well i have no idea, but I would guess at least a couple of square feet could be a lot more.


My guess is that to do this right you are looking at $3-5,000 in engineering costs, and $2-3,000 in build cost (for a commercial builder). Then a couple grand for the installation. So for $7-10,000 you can have a skeg hung rudder that is stronger than what you have now.

What we have all decided is that it is rediculious to do this, not that it can't be done. Just like you could design a mast that is twice as strong as whatyou have, but why?

[minaret]

Originally Posted by Stumble
In that case you need to hire a NA to design a new rudder and skeg. Figure you will need to remove 2 or 3 layers of glass within a foot or so of the new rudder post in order to bond the new skeg on, and likely reinforce the inside of the hull where the new skeg will be located.

The upside is you can likely go to a much thinner rudder post since the skeg will be carrying part of the load so you won't need the post to be as stiff.

Originally Posted by first wind

that's some good info. thanks.

Last time I glassed on a skeg, I did 14 plies in epoxy. This means you must first remove enough material for such a substantial laminate to be applied and still have a fair bottom. A few plies and one foot of back grind isn't even in the ballpark, IMHO.

[Dockhead]

Originally Posted by first wind

the question i have for you is why? just the usual nay saying when someone thinks to attempt/do something outside of the norm or is there a valid reason that it's physically not possible?

not trying to be a wise acre. i have just heard that a lot over the years. you know, "that can't be done" or more usually "you can't do that" or "it'll never work". so far, those voices have all proven wrong. i've accomplished a lot of things that people told me i'd never be able to do.

however, if there is a real reason that this undertaking might be undoable, that's the kind of info i am looking for. it let's me know what i am up against.

I have little to add to Stumble's excellent post, but the answer to the question "why", is economic. It's "physically possible", of course, but makes no sense at all. You can make an SUV out of a Mazda Miata, if you really want to, for example -- that's "doable". But why? Some facts.

1. You can't just slap on a skeg and have a stronger rudder.

2. You will have to throw away the existing rudder -- because it is "balanced", meaning part of it is ahead of the rudder post axis -- this doesn't work with a skeg. You will need a completely new, "unbalanced" rudder.

3. You will have to have it designed by a naval architect -- the hydrodynamics and structure of rudders are complex, and not to be home-made. This costs $$$

4. Making a skeg strong is actually much harder than making a spade rudder strong -- see Minaret's post. That's a whole lot of fiberglass work.

5. As someone said -- skeg rudders are hard to design well even when the boat is being designed from a clean sheet of paper, much less a retrofitted one. They have structural disadvantages compared to robust spade rudders. I agree with the person who said that you have a big risk of ending up with something weaker than what you started out with. To actually end up with something stronger, your naval architect will really have to work, sparing no expense.


As a result of which, you will spend a ton of money and time (I guess Stumble's guess is low, too -- ask better Minaret, who does these things professionally -- I would guess $20k might not even be enough), for a modification which will not add one dollar to the value of the boat, and in fact, will most likely make it worth less, because the boat will definitely sail worse with a skeg rudder, even if it ends up being stronger.


I agree with whoever said -- if you don't like the rudder, sell the boat and buy one with a rudder you do like. If you want an SUV, and you have a Miata, sell the Miata! Not because it's "undoable" to convert it to an SUV, but because it makes no sense.

[Jim Cate]

Originally Posted by first wind

the question i have for you is why? just the usual nay saying when someone thinks to attempt/do something outside of the norm or is there a valid reason that it's physically not possible?

not trying to be a wise acre. i have just heard that a lot over the years. you know, "that can't be done" or more usually "you can't do that" or "it'll never work". so far, those voices have all proven wrong. i've accomplished a lot of things that people told me i'd never be able to do.

however, if there is a real reason that this undertaking might be undoable, that's the kind of info i am looking for. it let's me know what i am up against.

FW, if you will take off the rose colored glasses and really read what Minaret and Stumble have now posted several times, you will see that this nay-saying is doing just what you have asked for in your last paragraph. Their views represent both engineering and very practical, high level trade skills, not "usual nay-saying".

In a previous post you said something about not having time to seek out a better suited boat. Do you really think that you can accomplish the skeg design and build in a short time? I do not, and I believe that all the pros who are following this conversation would agree. You have listed a number of beliefs about what constitutes a good boat for your proposed usage. The Cal meets essentially none of them... the skeg/spade controversy is but one.

I'll bow out now, but for your sake, please do consider what the pros are telling you.

Jim

[minaret]

Originally Posted by Jim Cate

FW, if you will take off the rose colored glasses and really read what Minaret and Stumble have now posted several times, you will see that this nay-saying is doing just what you have asked for in your last paragraph. Their views represent both engineering and very practical, high level trade skills, not "usual nay-saying".

In a previous post you said something about not having time to seek out a better suited boat. Do you really think that you can accomplish the skeg design and build in a short time? I do not, and I believe that all the pros who are following this conversation would agree. You have listed a number of beliefs about what constitutes a good boat for your proposed usage. The Cal meets essentially none of them... the skeg/spade controversy is but one.

I'll bow out now, but for your sake, please do consider what the pros are telling you.

Jim

Hey, for the record, I have no problem with what this guy is suggesting, given the caveat that he is a person who prefers working on boats to going sailing.