Are keelboats for cruising dead?

Discussion in 'Boat Design' started by Vineet, Jun 6, 2021.

  1. Rumars
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    Rumars Senior Member

    Sharpii, you should be much more differentiated in your opinion. Just some facts to consider:
    Long and low aspect ratio fin keels can have bolt on, or encapsulated ballast. It comes down to the orginal engineering and construction if you loose a keel or not, because it all depends on the underlying structure, just as with a high aspect ratio fin keel.
    Riding over an obstacle depends on the angle at the front of the keel. Plenty of high aspect fin keels are not arranged vertical, and don't have T shaped bulbs, giving them the same ability.
    Skegs are a very difficult piece of engineering because they are cantilevered from the hull skin, and take the bigger portion of the rudder pressure. Spade rudders are a simple proposition, you have a rudder stock supported by two points, it's simple to make it withstand any force you choose. The only advantage of a skeg hung rudder is protection from floating lines wich could wedge themselves between spade rudder and hull.

    If you are really concerned about impact and grounding your best bet is a full centerboarder with kick up rudders. If you hit something the appendages retract and the shallow dinghy like hull rides over the obstacles. If the boat is metal and has sufficient thickness in the bottom plate you can skid over granite and keep sailing. Most have full internal ballast and in the medium displacement group, wich makes them quite sea kindly, plus they retain all the advantages of having twin rudders and a good upwind foil.

    Just to be clear, I am not advocating for one form of boat over the other, all have strengths and weaknesses. If someone has design points that are specifically important to him, he should prioritize them and see where the SOR takes the design and what compromises he is willing to live with.
    bajansailor likes this.
  2. Milehog
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    Milehog Clever Quip

    Much of the fin keel issue is from builders cutting unseen corners or edgy racers. A moderate, well built fin keel is seaworthy. Badly built keels that fall off can come from budget Beneteau or expensive Oyster.
    Skegs have proven to be something of a security blanket. They look safe but can't really contribute any strength. If they had a spar going through the skeg up to the deck they could but they don't.
    There are plenty of clam crushers that aren't ocean worthy. What really matters is a moderate, balanced, competently engineered and built boat.
    bajansailor likes this.
  3. sharpii2
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    sharpii2 Senior Member

    A deep, high Aspect Ratio keel has a very small support area on the hull.

    It's not just a matter of fore and aft loads, when the bottom of the keel strikes an obstacle. It can be vertical ones too, when the top edge of the keel wants to push its way through the bottom of the boat.

    The designers try to take this into account by assuming a collision speed of around 3 to 5 kts. Unfortunately, these boats sail much faster than that, and it's not always obvious where these obstacles lurk.

    For a time, I was following a YouTube video of a couple who had purchased a boat with this sort of keel as salvage. It had suffered a keel strike, and the insurance company had written it off.

    The couple had found the damage more extensive than they originally thought, but went ahead anyway, doing the work themselves. They had to cut away much of the floor structure, which consisted of composite box beams, and rebuild it.

    Yeah, good engineering can overcome to some extent the the inherent vulnerability of this hull/keel type, but never totally.

    Spade rudders can be massively built, with large diameter shafts. I saw a Pearson 26 which had suffered a rudder strike. The shaft was bent maybe 5 to 10 degrees. But the rudder stayed on the boat, and it was still steerable.

    I also once saw a pretend skeg on a 27 ft Dufour. It was short and deep. And it had a very bad habit of breaking off.

    The owner had it replaced at least twice. But, once broken off, It affected the boat's performance insignificantly. The yard manager recommended not replacing it after the 2nd time it went AWOL. It's jagged stub was ground down and glassed over.

    But a real skeg is a major structural member of the hull. The kind I have in mind are as long at the top as they are deep and have a layup schedual befitting their role.

    I see a definite trade off between speed/windward performance and general durability.

    I would never argue that a well made high AR Fin keeler is inferior to a poorly made (or designed) crab crusher. But I would argue that one of equal quality is far more likely to survive a grounding mishap.
  4. wet feet
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    wet feet Senior Member

    We seem to be digressing into the realms of designing adequate internal structure.Which some builders of production boats do better than others.It is the case that a short, high aspect ratio keel will impose greater local loads than the long keel and like most things in life there are compromises between a desire for performance,access to shallow waters and the ability to look after the occupants of the boat if things get really wild.We may choose which corners of the performance envelope we would prefer our boats to occupy and we have to hope the designers and builders did a thorough job.It helps if we are honest with ourselves when making the choice since any number of us might dream of a life of ocean voyages and few of us actually do it.Its certainly something I have no wish to indulge in.
  5. sharpii2
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    sharpii2 Senior Member

    I think there are a few points from SEAWORTHINESS: THE FORGOTTEN FACTOR that are relevant to this discussion. The two main points in the book, which advocate for long keels boil down to:

    1.) directional stability. The argument is that, with the area of the keel spread out over the length of the WL, the boat is less likely to turn while having a wave at the bow and at the stern. The wave at the bow has orbital currents that run the opposite direction the wave is going. The wave at the stern lifts the stern of the boat, causing the boat to slide forward. This, the book says, can cause a considerable turning moment, which the long keel dampens.

    In retrospect, I'd say this is true, but it may not matter if the boat is moving with some speed. Then, maneuverability is what counts. It is here that the long keel quickly becomes a liability, because the very turn dampening that may keep the boat from broaching, while going slow, may actually cause it to do so, while going fast. The boat may get off course and turn too slowly to get back on course before the next wave hits and knocks it even further off course.

    2.) roll dampening. The long keel may have the same Vertical Center of Gravity as the short, deeper fin keel, because the ballast has more length to be distributed in, but the short, deep keel has far less roll dampening than the long keel does. In fact, the book claims with some evidence, the short, deep keel may actually induce rolling, as the boat is lifted an lowered by passing waves. The long keel, mainly because of its greater area, and that this area is distributed more towards the ends of the boat, making it more effective while the middle is in a wave trough, tends to dampen such rolling. This can be even more true if a wave hits the side of the boat. The book claims that the boat with the short, deep keel will roll more than the one with the shallower long keel. The long keel, not only dampens the original roll, but dampens the recovery roll as well, giving the boat an easier motion. This, the book says, is especially true if the mast is lost (the inertia of the mast also dampens rolls due to wave hits.).

    The book gives a chilling example of a fishing trowler that was built without a keel and was hit on its side by a medium sized wave, which rolled it completely upside down. It's anyone's guess if the same wave would had flipped if it had a long keel. The book implies it wouldn't, which now leaves me a bit skeptical.

    Those were the two main points of the book.

    My take now is that the long keel boat is safest when stopped in a storm, while the short keel boat is better off if sailed at some speed in such conditions.

    I also don't think the '79 Fastnet race disaster proved anything except how distructive the sea can be if you're caught in the wrong place at the wrong time.
  6. rangebowdrie
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    rangebowdrie Senior Member

    We see this kind of construction in Pacific Seacraft.
    It's also a staple in many of Ted Brewers designs.
    I first observed it on the Peterson 44s from the '70s,, kind of a "cut away" full keel.
  7. doogymon
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    doogymon Junior Member

    Awesome discussion and not to highjack but what do you guys think of this boat going offshore:

  8. bajansailor
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    bajansailor Marine Surveyor

    @doogymon most sailing yachts of this size should be capable of sailing offshore, provided that they are well maintained and properly equipped.

    Are you interested in purchasing a C & C like in your link?
    If yes, what sort of offshore sailing do you intend to do with her?
  9. rangebowdrie
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    rangebowdrie Senior Member

    Thankfully I've been spared truly horrific conditions.
    An old sailor that I knew, (since passed,) went thru a typhoon in which he tied himself to the cabin sole.
    Their was nothing else he could do,, the boat would have to fend for itself.
    It was a 40ft heavy disp. that drew ~7ft., wineglass sections, a lot of drag to the underbody profile, similar to an Alden Malabar.
    Anyway, yes, much of what I've followed on other forums from very experienced sailors tend to agree with you.
    Keep the lightweight boat moving,, then it becomes one of crew endurance.
  10. rangebowdrie
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    rangebowdrie Senior Member

    From the model name, and the ad/pics, it looks like the boat is exactly built for its purpose;
    To take a few guys offshore, (or not,) who will live in their foul weather gear for a day or a few, piss all over the forepeak trying to hit the bowl, eat simple fare, and try to win a trophy.
    If I wanted to single hand that boat to go long distances I would be glassing-in some structural foam to fill-in some of that space between the hull and the trailing edge of the fin.
    Also building up a skeg and re-configuring the rudder.
    The engine set-up is a disaster.
    Those changes would move the CLR aft,, so now I'll shift the CE by cutting the mast down a few feet, and lengthen the boom ~1.5ft.or so and add a forestay so that a snug close-coupled rig was available.
    The now shortened headstay would probably/maybe carry a rolled-up fairly high cut sail of ~90>100%,, kind of like a yankee.
    'Course we gotta do something about that forepeak/head set-up, and get some anchoring gear, and set-up a real galley.
  11. doogymon
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    doogymon Junior Member

    Hi BajanSailor

    I have owned this boat for a few years now.

    In doubt for offshore but the thought occupies my pea brain every 12.5 minutes or so....tehehe

    I sail/race/cruise her in the north parts of the Great Lakes.

    She sails like a son of a gun and still fast.

    Caught in a few blows and a reef or two I can take my hand off the wheel (has a wheel)...!

    The boat had massive refit a few years ago. The Deck is glassed at the hull/deck joint and the stanchions are out on the rail.

    I am berthed beside a famed and beautiful Contessa 32 and that boat looks tiny compared to this one-off C&C.

    The C&C won her class in 1971 Chicago Mack race.

    I read the thread and thought some of the comments were applicable .



  12. doogymon
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    doogymon Junior Member

    Hi rangebowdrie

    Yes yes the mast is tall eh? The winner of the Golden Globe race (Jean-Luc VDH) cut some his mast down on the Rustler 36.
    Yes I would love a full hoist Blade Jib and plan on acquiring one. Can I cut one out of my old tape-drive laminate genoa?
    She has a couple of stay sails (and a storm) rigged with a removable stay.
    The boat has a nice fat bottom and no pinch up at her quarters (zero IOR) and could maybe accommodate two rudders yes/no?
    The Galley has a bannister that holds the chief cook and bottle washer (also the skipper) very well.
    The layout of the boat makes it real easy to keep things organized and "pusser"....: ) Big toy boxes P/S up forward for sails and gear etc.
    Personally I think the boat is about 50 years ahead of her time but I might be a bit touched (biased).... : )
    Maybe prudent to just keep her the freshwater sea and tag a ride somewhere in the warm water.

    Cheers from Doog

    P.S. I'm just her keeper for a while.

  13. jakeeeef
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    jakeeeef Senior Member

    Interesting thread!

    As someone who edited a UK yacht cruising magazine between 2010 and 2014, when a lot of the big manufacturers were bringing out ever lighter designs, with their max beam carried further aft, my take on it at the time was:

    Actual displacement derived seaworthiness in bad weather (so matters including but not limited to ballast ratio, angle of vanishing stability), is of very little concern or interest to most boat buyers. And way outside of most buyers area of knowledge.
    And as mentioned earlier, for those few that do care, they can still buy a Rustler 44 or similar.

    Safety in bad weather is a non starter in selling boats, because despite the sea being as dangerous as it ever was ( except maybe now arguably more so due to increased extreme weather events), human nature says -it'll never happen to me'.

    Volvos are perceived safer than porsches, but at the luxury and performance end, what would most people rather have? ( All boats are a luxury purchase, so buyers usually have their Porsche hat on, not their Volvo hat).

    Making monohulls beamy aft has the other effect of getting an owner's aft cabin of generous proportions back there. Very important when most boat sales are allegedly given the final yay or nay by the wife or girlfriend. 1970s man had a lot more say on what sort of boat he bought than he does now.

    People have shorter holidays and work harder than they used to and boats are proportionately much more expensive than they used to be. So if you're only using your boat a few weeks a year, you'll pick the nice, sunny ones, and the sort of boat that would be most fun for them, with lots of deck space and good performance with the wind abeam or abaft the beam. Gone are the days when a working chap will pack his young family into the westerly centaur in their vomit-flecked oilskins and beat over the channel for 18 hours.

    Performance/ aspiration. People want to look like thier boat just won the Vendée Globe.
    So progress, or perception of progress. People spending an offensive amount of money want something that looks ' modern', like it's had R & D cash spent on it. So something that looks very different from a 1960s cruising yacht.

    All the navigation and safety electronics, weather forecasting and composites improvements have helped make all this happen, but it's those more fundamental societal drivers above that are the cause.
    And of course genuine progress has also been made in with all the marketing puff. We didn't buy these sort of cruising yachts in the 60 s because they didn't exist. And it's genuinely the case that they wouldn't be quite as capable as they are without things like the Mini Transat and Vendée Globe.

    Please note, all of the above was not conjecture, as a traditional sailor, brought up on heavier displacement boats and concerned about where things were headed, I asked every manufacturer I dealt with at the time ( including all of the big manufacturers) about this.

    They all said the same thing, you have to make what the people want to buy. Whether or not you agree it's what they should have is irrelevant.

    I also had an illuminating chat with RKJ once about a very similar subject. He was changing the old Clipper race fleet to much more modern lighter displacement yachts with assymetric spinnakers, full planing downwind performance etc. I think it was around 2012 ish. I was interested to know what someone who had sailed round the world at 3 knots thought of doing 30 knots.

    I won't mention exactly what he said as it's potentially libelous and crew have been sadly lost on his subsequent races, but suffice to say he felt he had no choice, commercially, but offer ' something that looked like a Volvo Ocean Race yacht' of the time. The design was greatly detuned, with about 10 feet off the mast, but I did detect he had some concerns about the way the necessity to keep in business and offer what the customers wanted was forcing him to go.
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