Centerboard yachts dis/advantages
mangl...@yahoo.com
I saw an ad for a 37 foot yacht (Dockrell 37) with a centreboard
instead of a keel and googled a bit. One of the references said that
there are advantages to having a centerboard in shallop coastal waters
(clearly) but that it wasn't as successful in UK deep coastal waters.
I was just wondering what the disadvantages of a centerboard in this
sized yacht are ? I would be keeping her on a drying (mud) berth so
the pros of just being able to leave her there with the centrboard up
are obvious for me, but the only disadvantage I've been able to
identify from the internet are clonking noises from the board while
sailing. Any others come to mind ?
Many thanks,
David
Duncan Heenan
news:3aed03c9-1257-4aaa...@r31g2000vbi.googlegroups.com...
A lifting keel is just one more thing to go wrong. If the lifting/lowering
mechanism malfunctions you're left with the keel either stuck up (making the
boat unstable to sail), or down (making the boat unsafe to take the ground),
or somewhere in-between. OK so it may not happen, but if it does it is most
inconvenient, possibly even dangerous in the wrong circumstances.
Also, check out the weight and weight distribution of the 'centerboard'
compared with, say, a bulb/fixed keel. If (as is usual) it is much lighter
and the weight is not low down, it will mean that the boat will heal more
and the up-wind performance is likely to be worse than a heavier fixed keel.
However, lifting keel boats are still made, some quite big ones, so
obviously they're not all bad.
--
Duncan Heenan
Dave Doe
@r31g2000vbi.googlegroups.com>, mangl...@yahoo.com says...
Clonking noises? Naa, they don't do that - unless you leave 'em down
when anchored or moored and there's a bit of a sea - *then* they clonk.
Under sail I've never encountered any clonking noises - obviously while
tacking they certainly don't. Perhaps some do downwind. That said, for
some extra speed, you can wind it up when going downwind. You should
check that the boat will self-right when the keel is raised! :) (many
won't!). And on that, when down, is it able to be locked in the down
position, as, in the event of a serous knock-down, it's possible the
keel could slide back into a retracted, or semi-retracted position, and
the boat not self-right.
The other big factor in retracting keels is maintenance - it's vital you
observe the manufacturers recommendations. As Duncan H has pointed out,
you never want these things to fail. Obvious thinks to check on most
retractable keels are the main bearings and rod and the raising/lowering
mechanism (wire usually).
On my trailer-sailer, a Farr 7500 (7.5m / 25') she has a solid cast-iron
keel that swings down (320Kg IIRC), and a rope mechanism to lock it
down. And a geared wire mechanism that is self-braking to raise and
lower it.
Your 37' boat maybe quite different of course - and as said, it's
important to follow the manufacturers maintenance instructions and
operating instructions.
It's also not uncommon to stop clonking, by fitting a mylar or similar
plastic strip each side of the 'slot' - typically fastened by an ali or
brass strip. These also increase performance slightly, and reduces (and
often completely stops) water surging up through the slot casing and
into the boat. (That happens on my boat above 10-12 kts under
spinnaker.)
I love my wee retractable keel trailer-sailer - one can head into waters
as little as 18" - and still get great sailing performance (draws 6'
when lowered) when sailing. I would imagine they'd be great in Britain
too with all the rivers and estuaries to explore.
--
Duncan.
http://hitime.no-ip.info/
TonyB
"Dave Doe" <ha...@work.ok> wrote in message
news:MPG.257533e0b...@news.eternal-september.org...
There's a difference between lifting centreboard and swing keels. The Doc
is the latter I believe. If a swing keel swings backwards as most do, then
you have
an advantage over all other types of keel in that if you run aground the
keel will
swing back with minimal damage.
When you say it's not as successful in UK deep coastal waters, the question
is,
not as successful as what? I can only think that they refer to a long keel
boat
like Tony's Nic 32, which of course will have better sea keeping qualities,
but otherwise there should be little difference between
swing, lift and fixed fin keels. If you're going to be picky, maybe it's
possible that a fixed keel can hold more ballast as you can shape a fixed
keel
where as a lift keel needs to be pretty much a flat plate.
TonyB
Dave Doe
hatt.j....@tesco.net says...
As is my boat - yep, an advantage I believe.
>
> When you say it's not as successful in UK deep coastal waters, the question
> is,
> not as successful as what? I can only think that they refer to a long keel
> boat
I'm confused as to where you read that from my reply. I don't think I
said that at all. On the contrary, they are probably a better sailing
configuration than fixed twin keels (probably draw less when raised, and
probably perform better when lowered).
> like Tony's Nic 32, which of course will have better sea keeping
qualities,
> but otherwise there should be little difference between
> swing, lift and fixed fin keels. If you're going to be picky, maybe it's
> possible that a fixed keel can hold more ballast as you can shape a fixed
> keel
> where as a lift keel needs to be pretty much a flat plate.
Yep, that's about it. That said, my swing keel configuration is a cast-
iron bladed keel (not just a flat plate) - so it has the shape of a
normal fin keel.
--
Duncan.
TonyB
>> question
>> is,
>> not as successful as what? I can only think that they refer to a long
>> keel
>> boat
>
> I'm confused as to where you read that from my reply. I don't think I
> said that at all. On the contrary, they are probably a better sailing
> configuration than fixed twin keels (probably draw less when raised, and
> probably perform better when lowered).
I read it from your post of 23/11 when you replied to Duncan:
"One of the references said that
> there are advantages to having a centerboard in shallop coastal waters
> (clearly) but that it wasn't as successful in UK deep coastal waters."
I was deliberately avoiding the issue of twin keels as they are
controversial!
TonyB
mangl...@yahoo.com
>
> "One of the references said that
>
> > there are advantages to having a centerboard in shallop coastal waters
> > (clearly) but that it wasn't as successful in UK deep coastal waters.
That wasn't him, it was me. I have just googled but can't find the
reference again unfortunately - it was in a potted history of Dockrell
yachts somewhere on the web and I was just curious to know what the
sailing dis/advantages of a swing keel are.
Thanks to all for the answers,
David
Dave Doe
hatt.j....@tesco.net says...
Yeah, as David says - that wasn't me :)
I should add, that - unlike twin-keels, some centerboard'ers - like
mine, have a fixed portion - a keel - which means without "sea-legs"
fitted - they "fall over" when on the mud. Not a lot, but enough to
make for an uncomfortable night and tricky cooking! - etc :)
eg.
http://hitime.no-ip.info/Hi%20Time%20goes%20back%20on%20the%
20trailer/target1.html
--
Duncan.
Dave Doe
ha...@work.ok says...
>
> In article <S9WdnUNJEcDQmpDW...@bt.com>,
> hatt.j....@tesco.net says...
> >
> > >> When you say it's not as successful in UK deep coastal waters, the
> > >> question
> > >> is,
> > >> not as successful as what? I can only think that they refer to a long
> > >> keel
> > >> boat
> > >
> > > I'm confused as to where you read that from my reply. I don't think I
> > > said that at all. On the contrary, they are probably a better sailing
> > > configuration than fixed twin keels (probably draw less when raised, and
> > > probably perform better when lowered).
> >
> > I read it from your post of 23/11 when you replied to Duncan:
> >
> > "One of the references said that
> > > there are advantages to having a centerboard in shallop coastal waters
> > > (clearly) but that it wasn't as successful in UK deep coastal waters."
> >
> > I was deliberately avoiding the issue of twin keels as they are
> > controversial!
>
> Yeah, as David says - that wasn't me :)
I meant TonyB! - I had two whiskys last night, only! - promise. Will
have another coffee :)
--
Duncan.