Because you'll have to add more lead below the waterline to keep the weedy
side of the boat down?

Because it will tend to lift off the pintles which have to take the weight
when the boats hauled? (reversing loads are worse than unidirectional
loads)

Why would you want to make it lighter?

In real life it probably doesn't matter much, but then that's the basis for
any heated discussion.

Roger

http://home.insightbb.com/~derbyrm

"Martin Schöön" wrote in message
news
On Sun, 09 Apr 2006 01:17:53 +0000, derbyrm wrote:

Since no one else is jumping in, I'll offer my opinion.

The rudder should not float.

Why not?
My rudder do definitely float and have worked just fine for
19 seasons. If I had the time I would make new pair out of
carbon - even lighter.

/Martin

If you have a raked rudderpost as on my old Wharram cat. a bouyant rudder
blade causes the rudder to float up towards one side or the other, not a big
problem in normal conditions, but in very light wind it could make things
difficult for the selfsteering, also caused an annoying rattling noise,
mainly noticeable at anchor- especially in a bit of a chop.

"derbyrm" skrev i en meddelelse
news:a_6_f.886669$x96.292143@attbi_s72...
Because you'll have to add more lead below the waterline to keep the weedy
side of the boat down?

On Sun, 09 Apr 2006 12:20:23 +0000, derbyrm wrote:

Because you'll have to add more lead below the waterline to keep the weedy
side of the boat down?

In theory maybe and only for a lead-swinger. But if you play around
a little with numbers I bet you will find the rudder must be a monster
to make a useful contribution to righting moment.

Because it will tend to lift off the pintles which have to take the weight
when the boats hauled? (reversing loads are worse than unidirectional
loads)

Again, a monster of a rudder, in terms of volume this time, is
needed make this a *real* problem.

Why would you want to make it lighter?

Because it is possible.
Because less weight in the ends means less pitching.
Because lighter is faster.
Because it is a hobby of mine to tinker with my boat.
http://hem.bredband.net/b262106/

In real life it probably doesn't matter much, but then that's the basis for
any heated discussion.

:-)

/Martin

"Martin Schöön" wrote in message
news
On Sun, 09 Apr 2006 12:20:23 +0000, derbyrm wrote:

Because you'll have to add more lead below the waterline to keep the
weedy side of the boat down?

In theory maybe and only for a lead-swinger. But if you play around
a little with numbers I bet you will find the rudder must be a monster
to make a useful contribution to righting moment.

Because it will tend to lift off the pintles which have to take the
weight
when the boats hauled? (reversing loads are worse than unidirectional
loads)

Again, a monster of a rudder, in terms of volume this time, is
needed make this a *real* problem.

Actually, I'm picturing a boat at anchor in a chop (as someone mentioned)
with the rudder banging up and down as the water comes and goes. Noise is
BAD.

Why would you want to make it lighter?

Because it is possible.
Because less weight in the ends means less pitching.

Is this that monster rudder we aren't talking about? Where do you stow your
anchor and chain?

Because lighter is faster.

In light airs. In a chop, weight keeps you going. Sail planes carry water
ballest for better speed and range.

Because it is a hobby of mine to tinker with my boat.
http://hem.bredband.net/b262106/

In real life it probably doesn't matter much, but then that's the basis
for
any heated discussion.

:-)

/Martin

I'm planning on adding lead ballast to my rudder stock to keep the assembly
firmly on the pintle. (After I trim the bottom half inch of the stock off).

Roger

http://home.insightbb.com/~derbyrm

derbyrm wrote:
I'm planning on adding lead ballast to my rudder stock to keep the assembly
firmly on the pintle. (After I trim the bottom half inch of the stock off).


"The only vehicle that benefits from added weight is a
steamroller" -Uffa Fox

You should consider a latch to hold the rudder on it's
pintles. There are a number of quite simple & effective ones
available off the shelf.

Making it heavier will increase loads on the pintles &
gudgeons, on the transom, will change the balance of the
boat & make it pitch more, and if the boat is ever in enough
motion or at such an attitude that the weight is no longer
pulling straight down, you have lost all benefit and kept
the negatives.

Fresh Breezes- Doug King

Well, maybe, but we're talking about adding a couple of pounds to a 1500
pound boat. The "pintle" is not the ordinary rowboat stern device, and
there's no place for a latch.

For pitching moment, I'm a lot more concerned with the chain portion of the
anchor rode which will be stowed in the very bow.

Mr. Fox seems to disagree with Phillip C. Bolger. In "Thirty Odd Boats"
PCB, commenting on Herreshoff's Rosinante suggests that "half the weight in
that 3000 lb. keel is to give the boat momentum."

Roger

http://home.insightbb.com/~derbyrm

"DSK" wrote in message
...
derbyrm wrote:
I'm planning on adding lead ballast to my rudder stock to keep the
assembly firmly on the pintle. (After I trim the bottom half inch of the
stock off).

"The only vehicle that benefits from added weight is a steamroller" -Uffa
Fox

You should consider a latch to hold the rudder on it's pintles. There are
a number of quite simple & effective ones available off the shelf.

Making it heavier will increase loads on the pintles & gudgeons, on the
transom, will change the balance of the boat & make it pitch more, and if
the boat is ever in enough motion or at such an attitude that the weight
is no longer pulling straight down, you have lost all benefit and kept the
negatives.

Fresh Breezes- Doug King

derbyrm wrote:
Well, maybe, but we're talking about adding a couple of pounds to a 1500
pound boat. The "pintle" is not the ordinary rowboat stern device, and
there's no place for a latch.


If there's no place on the stern for a latch, that suggests
that there's no stern. This idea might work and also look
salty, a short rope strop tensioned (slightly) upward from
the stern to a cleat on the rudder cheek.


For pitching moment, I'm a lot more concerned with the chain portion of the
anchor rode which will be stowed in the very bow.


Also a bad idea IMHO. Why not stow it amidships? Why carry
so much chain in the first place? Because it's manly?


Mr. Fox seems to disagree with Phillip C. Bolger. In "Thirty Odd Boats"
PCB, commenting on Herreshoff's Rosinante suggests that "half the weight in
that 3000 lb. keel is to give the boat momentum."


If we could get the two together, I'm sure it would be an
interesting discussion. In any case, the weight fo the
Rozinante keel is really there for righting moment. Momentum
may be a benefit in some situations, a detriment in others.
If the same righting moment could be had with less weight
(all else being equal), you can be assured that a designer
of L.F. Herreshoff's caliber (or Bolger's, he's certainly no
slouch) would jump on it.

DSK

You can check out the bottom most pictures at
http://home.insightbb.com/~derbyrm/Chebacco.html to see what I'm dealing
with. I guess I could put a collar on the rudder shaft below the cross
piece, but it adds complexity while my solution is simpler. I replaced the
specified SS tube with PVC and want to get back toward the designed weight.
That should be $$ based on my shopping for a three foot length of 2" 316
Stainless, PCB's recommendation.

Even a short (20 to 30 foot) length of chain adds a lot of weight. It's
there to increase holding power at limited scope and to limit the ground
debris' damage to the rode. The real cruisers, manly and womanly, favor all
chain rode.

Stowage amidships has been done, but it's a really difficult thing to do
well. Put it amidships and you've diced the cabin with the hawse tube. Put
it to one side and, over time, one of your legs gets shorter.

Roger

http://home.insightbb.com/~derbyrm
"DSK" wrote in message
...
derbyrm wrote:
Well, maybe, but we're talking about adding a couple of pounds to a 1500
pound boat. The "pintle" is not the ordinary rowboat stern device, and
there's no place for a latch.


If there's no place on the stern for a latch, that suggests that there's
no stern. This idea might work and also look salty, a short rope strop
tensioned (slightly) upward from the stern to a cleat on the rudder cheek.


For pitching moment, I'm a lot more concerned with the chain portion of
the anchor rode which will be stowed in the very bow.


Also a bad idea IMHO. Why not stow it amidships? Why carry so much chain
in the first place? Because it's manly?


Mr. Fox seems to disagree with Phillip C. Bolger. In "Thirty Odd Boats"
PCB, commenting on Herreshoff's Rosinante suggests that "half the weight
in that 3000 lb. keel is to give the boat momentum."


If we could get the two together, I'm sure it would be an interesting
discussion. In any case, the weight fo the Rozinante keel is really there
for righting moment. Momentum may be a benefit in some situations, a
detriment in others. If the same righting moment could be had with less
weight (all else being equal), you can be assured that a designer of L.F.
Herreshoff's caliber (or Bolger's, he's certainly no slouch) would jump on
it.

DSK

On Mon, 10 Apr 2006 12:57:51 +0000, derbyrm wrote:


Mr. Fox seems to disagree with Phillip C. Bolger. In "Thirty Odd Boats"
PCB, commenting on Herreshoff's Rosinante suggests that "half the weight in
that 3000 lb. keel is to give the boat momentum."

Recommended reading:

Chapter XVIII "The Sailing Machine" in "The Common Sense of Yacht Design"
by L. Francis Herreshoff. (volume II)

/Martin

On Mon, 10 Apr 2006 12:57:51 GMT, "derbyrm"
wrote:

Mr. Fox seems to disagree with Phillip C. Bolger. In "Thirty Odd Boats"
PCB, commenting on Herreshoff's Rosinante suggests that "half the weight in
that 3000 lb. keel is to give the boat momentum."

The keel is the only part of a sailboat that benefits from weight, and
even there it should be limited to just what is necessary.