Re: Gypsy Daggerboard relocation
Dan --
I'm not crazy about the Gypsy daggerboard either, but for different
reasons. As it is, off-center and angled, when you're sailing over a
sandbar, or approaching a beach, on a port tack, you need to pull the
board up -- and it bumps into the sail, sometimes causing trouble --
i.e. board scraping bottom as sail pushes against it, causing boat to
pivot on board, heel over, etc.
Also, any such urgent need to raise the board necessitates a move way
forward just as you're also needing a little extra care at the
tiller.
SO, a pivoting centerboard would be a huge improvement for shoal
sailing. But, as Keith points out, this is not easily done. It would
interfere with the rowing thwart. I haven't really sketched this out
or imagined it in enough detail, but it seems one possibility would
be to install a real pivoting CB, using a long and narrow CB
(calculating its dimensions to keep center of lateral resistance the
same), so the top of the CB case is just above the load waterline of
the boat. You'd have problems with spray bubbling into the boat, but
maybe a gasket of some sort would keep it to a minimum.
Your thwart would be high -- causing a higher center of gravity when
rowing -- but that's when CG matters least -- you have oars to
stabilize you and no massive heeling arm from the sail.
OK -- I'll stop woolgathering and leave this to you. Let us know how
you work it out. From the accumulated replies, you can see what a
dicey business it is messing with the designs of a boat. But still,
it's fun to think about.
All best,
Garth
I'm not crazy about the Gypsy daggerboard either, but for different
reasons. As it is, off-center and angled, when you're sailing over a
sandbar, or approaching a beach, on a port tack, you need to pull the
board up -- and it bumps into the sail, sometimes causing trouble --
i.e. board scraping bottom as sail pushes against it, causing boat to
pivot on board, heel over, etc.
Also, any such urgent need to raise the board necessitates a move way
forward just as you're also needing a little extra care at the
tiller.
SO, a pivoting centerboard would be a huge improvement for shoal
sailing. But, as Keith points out, this is not easily done. It would
interfere with the rowing thwart. I haven't really sketched this out
or imagined it in enough detail, but it seems one possibility would
be to install a real pivoting CB, using a long and narrow CB
(calculating its dimensions to keep center of lateral resistance the
same), so the top of the CB case is just above the load waterline of
the boat. You'd have problems with spray bubbling into the boat, but
maybe a gasket of some sort would keep it to a minimum.
Your thwart would be high -- causing a higher center of gravity when
rowing -- but that's when CG matters least -- you have oars to
stabilize you and no massive heeling arm from the sail.
OK -- I'll stop woolgathering and leave this to you. Let us know how
you work it out. From the accumulated replies, you can see what a
dicey business it is messing with the designs of a boat. But still,
it's fun to think about.
All best,
Garth
The daggerboard is offset so it clears the mast as you pull it out of
its slot, and it's angled to clear the rowing thwart. The thwart is
located to balance the boat with a single oarsman. It is, alas, all
connected. I always thought the Gypsy would be quite a lot handier
with a pivoting centerboard, but I never came up with a way to do it
that looked like it would work well enough to try. Honestly, I
didn't notice that the board was offset anymore after a week or so,
and no one ever commented on it, but it's your boat . .
If the fore and aft position of the geometrical center of the
daggerboard's underwater part stays the same (within an inch or so -
no point in being fanatical) the helm balance won't change
noticeably. Gypsy has a very big rudder for her size, which makes
her fairly forgiving of such experiments. So, if you moved the
daggerboard case a bit aft, made the daggerboard more vertical, moved
the thwart a bit aft as well, and could tolerate her being a just a
little down by the stern when rowing, IMHO it'd probably work fine.
The rowing thwart would probably need to partially overlap the frame
at station 9, but that's OK, although there are some details of the
seat mountings that you'll have to work out. I still don't think
it's worth the trouble, but again, it's your boat.
Have fun with your Gypsy! She's a great little boat, and will
improve the scenery wherever she goes; I wish I still had mine.
She's the example I always use to refute those who claim that simple
taped-seam boats have to be ugly.
BTW, the Gypsy desperately needs a modest skeg for directional
stability while rowing - see Cartopper for the pattern.
its slot, and it's angled to clear the rowing thwart. The thwart is
located to balance the boat with a single oarsman. It is, alas, all
connected. I always thought the Gypsy would be quite a lot handier
with a pivoting centerboard, but I never came up with a way to do it
that looked like it would work well enough to try. Honestly, I
didn't notice that the board was offset anymore after a week or so,
and no one ever commented on it, but it's your boat . .
If the fore and aft position of the geometrical center of the
daggerboard's underwater part stays the same (within an inch or so -
no point in being fanatical) the helm balance won't change
noticeably. Gypsy has a very big rudder for her size, which makes
her fairly forgiving of such experiments. So, if you moved the
daggerboard case a bit aft, made the daggerboard more vertical, moved
the thwart a bit aft as well, and could tolerate her being a just a
little down by the stern when rowing, IMHO it'd probably work fine.
The rowing thwart would probably need to partially overlap the frame
at station 9, but that's OK, although there are some details of the
seat mountings that you'll have to work out. I still don't think
it's worth the trouble, but again, it's your boat.
Have fun with your Gypsy! She's a great little boat, and will
improve the scenery wherever she goes; I wish I still had mine.
She's the example I always use to refute those who claim that simple
taped-seam boats have to be ugly.
BTW, the Gypsy desperately needs a modest skeg for directional
stability while rowing - see Cartopper for the pattern.
--- Inbolger@egroups.com, "dan " <dan@g...> wrote:
> Greetings:
>
> I'm going to build a Gypsy. I've got my plans, and I'm getting
> ready to go and I've got a question for the group.
>
> The offset daggerboard in Gypsy bothers me, but for no logical
> reason other than it's not symmetric. I'd like to get it located
> in
> the center of the boat. What are some thoughts on:
>
> 1. Relocating the daggerboard towards the stern so that it can
> be centrally placed? Will that adversely affect the handling?
>
> 2. Modifying the daggerboard itself so that it's horizontal, and
not
> at an angle?
>
> 3. Some other modification to the daggerboard to place it in the
> center of the floor?
>
> Also, if so advised, I'll leave the daggerboard and case as
> determined in the plans and learn to live with it.
>
> Thanks for your insight,
>
> Dan
> The offset daggerboard in Gypsy bothers me, but for no logicalDan,
> reason other than it's not symmetric.
From a quick glance at the plans, it looks to me like the reason for
the off-center location is so that the daggerboard will pass beside
the mast on the way in or out. If the trunk were centered, the mast
would block movement of the board.
I would think that it would be possible to use a more vertical board,
and I do not know why PCB did not do so. Possible reasons that come
easily to mind are (1) the way it is, the front of the daggercase is
landed on a frame (it would otherwise require reinforcement), (2)
shallower draft on a given board, (3) the raked board will collect
less seaweed and may be more better for high speed sailing, (4) if
the board were upright, it would have to pass through the frame which
is now just aft of it (which would mean, in effect that the frame
would have to be at least moved and possibly replaced by two frames).
These s&g boats required a lot of internal framing, and possibly PCB
thought this made the cleanest boat.
Once you get the boat built, you will forget about the off-
centeredness.
By the way, are you ambidextrous?
Peter
On Wed, 10 Jan 2001, dan wrote:
Not only does it affect the "lead" from the center of effort to the center
of lateral resistance, it also affects handling, in terms of turning and
tracking. Do not make such changes lightly--it could turn your boat into
an unmanageable dog.
difficult to hold the boat on course when going to windward.
affect the center of lateral resistance, although less so. Michalak has
argued that small changes like these don't seem to make much difference,
but I wonder how "small" small is.
much. But ask yourself--why is it off-center? To make more useable space
within the boat? To avoid a cross-beam thwart?
My guess is that your aesthetic sense is affronted by the off-center
daggerboard. But if your primary concern here is aesthetics, you might
consider that you are building a Bolger Gypsy, and it has an aesthetics of
its own of a very peculiar kind. I would swallow my pride and live with
the idea Bolger promulgates here. It's functional, and that is the
primary aesthetic of most of Bolger's boats.
advice from others on the list.
-Chris
> The offset daggerboard in Gypsy bothers me, but for no logical reasonThis is a non-trivial issue, because it affects performance so strongly.
> other than it's not symmetric. I'd like to get it located in the
> center of the boat. What are some thoughts on:
Not only does it affect the "lead" from the center of effort to the center
of lateral resistance, it also affects handling, in terms of turning and
tracking. Do not make such changes lightly--it could turn your boat into
an unmanageable dog.
> 1. Relocating the daggerboard towards the stern so that it can beOh, certainly. It will give you lee helm up the wazoo, and make it
> centrally placed? Will that adversely affect the handling?
difficult to hold the boat on course when going to windward.
> 2. Modifying the daggerboard itself so that it's horizontal, and notLess of a problem, but I wonder why you'd like to do it. It, too, will
> at an angle?
affect the center of lateral resistance, although less so. Michalak has
argued that small changes like these don't seem to make much difference,
but I wonder how "small" small is.
> 3. Some other modification to the daggerboard to place it in theWell, you could simply move it to the center. This probably wouldn't do
> center of the floor?
much. But ask yourself--why is it off-center? To make more useable space
within the boat? To avoid a cross-beam thwart?
My guess is that your aesthetic sense is affronted by the off-center
daggerboard. But if your primary concern here is aesthetics, you might
consider that you are building a Bolger Gypsy, and it has an aesthetics of
its own of a very peculiar kind. I would swallow my pride and live with
the idea Bolger promulgates here. It's functional, and that is the
primary aesthetic of most of Bolger's boats.
> Also, if so advised, I'll leave the daggerboard and case as determinedWell, I advise it, but my second piece of advice is to wait for more
> in the plans and learn to live with it.
advice from others on the list.
-Chris
At 06:14 PM 1/10/2001 -0000, you wrote:
probably lose your weather helm, which is a natural safety feature. You
might even find your rudder too small, in light air, heavy air, adverse
conditions - just when you need it, there may be no telling which way your
boat and crew will go!
Other than that, I don't think the board's placement matters much... ;-}
Gregg Carlson
>I'm going to build a Gypsy. I've got my plans, and I'm gettingAbsolutely - it will throw the boat and its helm off a balance. You'll
>ready to go and I've got a question for the group.
>
>The offset daggerboard in Gypsy bothers me, but for no logical
>reason other than it's not symmetric. I'd like to get it located
>in the center of the boat. What are some thoughts on:
>
>1. Relocating the daggerboard towards the stern so that it can
>be centrally placed? Will that adversely affect the handling?
probably lose your weather helm, which is a natural safety feature. You
might even find your rudder too small, in light air, heavy air, adverse
conditions - just when you need it, there may be no telling which way your
boat and crew will go!
Other than that, I don't think the board's placement matters much... ;-}
Gregg Carlson
>2. Modifying the daggerboard itself so that it's horizontal, and not
>at an angle?
>
>3. Some other modification to the daggerboard to place it in the
>center of the floor?
>
>Also, if so advised, I'll leave the daggerboard and case as
>determined in the plans and learn to live with it.
>
>Thanks for your insight,
>Dan
>
>Bolger rules!!!
>- no cursing, flaming, trolling, or spamming
>- no flogging dead horses
>- add something: take "thanks!" and "ditto!" posts off-list.
>- stay on topic and punctuate
>- add your comments at the TOP and SIGN your posts
Greetings:
I'm going to build a Gypsy. I've got my plans, and I'm getting
ready to go and I've got a question for the group.
The offset daggerboard in Gypsy bothers me, but for no logical
reason other than it's not symmetric. I'd like to get it located
in
the center of the boat. What are some thoughts on:
1. Relocating the daggerboard towards the stern so that it can
be centrally placed? Will that adversely affect the handling?
2. Modifying the daggerboard itself so that it's horizontal, and not
at an angle?
3. Some other modification to the daggerboard to place it in the
center of the floor?
Also, if so advised, I'll leave the daggerboard and case as
determined in the plans and learn to live with it.
Thanks for your insight,
Dan
I'm going to build a Gypsy. I've got my plans, and I'm getting
ready to go and I've got a question for the group.
The offset daggerboard in Gypsy bothers me, but for no logical
reason other than it's not symmetric. I'd like to get it located
in
the center of the boat. What are some thoughts on:
1. Relocating the daggerboard towards the stern so that it can
be centrally placed? Will that adversely affect the handling?
2. Modifying the daggerboard itself so that it's horizontal, and not
at an angle?
3. Some other modification to the daggerboard to place it in the
center of the floor?
Also, if so advised, I'll leave the daggerboard and case as
determined in the plans and learn to live with it.
Thanks for your insight,
Dan