Well its time to make my rudder, for a tiller steered 34 foot Van de
Stadt. Now Van de Stadt have given me a nice drawing showing three
types of construction:

wood strips with a gap of around 1 3/4" between the strips, filled
with polyurethane foam, and covered with a plywood skin.

Solid plywood panels glued together and shaped

foam with a epoxy and glass fibre skin.

any of the above seems ok (apart from perhaps the plywood one may be a
bit heavy?)

but is it possible ( perhaps the stupid question) to make a rudder the
salme way as my hull ie; western red cedar strips laminated with a
fibreglass and epoxy skin? Its seems pretty tough now my hull is made
and for me it may be easier to make and fit on my rudder stock. It
seems to me it would be at least as strong as a foam rudder, and
almost as light.

BTW, the first construction method doesn't make the rudder shaft
manufactureres (Jefa) squeal with joy.

Pete,

I noticed a distinct dearth of replies to your question.

Of the more than a few rudders and have never made a strip
planked one.

There is no reason why you could not, but there are some
considerations that you should think through.

A rudder must contain structure to secure it to the
shank/shaft with complete confidence as anything less will
be a serious problem at some inopportune point.

Most rudders live their entire lives submerged (and you are
thinking - so does the hull), but unlike the hull they have
a required breach where the shank enters the structure
and/or is fastened. Treating this breach like a
through-hull fitting is not applicable as there will be
forces and loads present that are much different than a
static fitting.

With any possible breach, the core (be it wood or foam) will
absorb water.

So, If you have a plan that can make it work, go for it.
That fact that it hasn’t been dome before is not a reason.

By the by - a foam rudder as you are calling it gets little
or none of its strength from the foam. The foam is just
there to a: either be a form for the laminate to build on or
b: something to keep the rudder from completely filling with
water.

Best of Luck

Matt Colie a Lifelong Waterman, Licensed Mariner and
Congenital Sailor

pete wrote:
Well its time to make my rudder, for a tiller steered 34 foot Van de
Stadt. Now Van de Stadt have given me a nice drawing showing three
types of construction:

wood strips with a gap of around 1 3/4" between the strips, filled
with polyurethane foam, and covered with a plywood skin.

Solid plywood panels glued together and shaped

foam with a epoxy and glass fibre skin.

any of the above seems ok (apart from perhaps the plywood one may be a
bit heavy?)

but is it possible ( perhaps the stupid question) to make a rudder the
salme way as my hull ie; western red cedar strips laminated with a
fibreglass and epoxy skin? Its seems pretty tough now my hull is made
and for me it may be easier to make and fit on my rudder stock. It
seems to me it would be at least as strong as a foam rudder, and
almost as light.

BTW, the first construction method doesn't make the rudder shaft
manufactureres (Jefa) squeal with joy.

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

The rudder should not float. The solid plywood panels are a technique I
understand, and with some lead or ??? will be at least neutral.

The critical thing is the rudder shape (air foil).

Trying to steer when the rudder head twists with respect to the rest of the
blade is BAD! (been there, done that)

Roger

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

"pete" wrote in message
...
Well its time to make my rudder, for a tiller steered 34 foot Van de
Stadt. Now Van de Stadt have given me a nice drawing showing three
types of construction:

wood strips with a gap of around 1 3/4" between the strips, filled
with polyurethane foam, and covered with a plywood skin.

Solid plywood panels glued together and shaped

foam with a epoxy and glass fibre skin.

any of the above seems ok (apart from perhaps the plywood one may be a
bit heavy?)

but is it possible ( perhaps the stupid question) to make a rudder the
salme way as my hull ie; western red cedar strips laminated with a
fibreglass and epoxy skin? Its seems pretty tough now my hull is made
and for me it may be easier to make and fit on my rudder stock. It
seems to me it would be at least as strong as a foam rudder, and
almost as light.

BTW, the first construction method doesn't make the rudder shaft
manufactureres (Jefa) squeal with joy.

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

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

On Thu, 06 Apr 2006 13:16:26 +0200, pete wrote:

Well its time to make my rudder, for a tiller steered 34 foot Van de
Stadt. Now Van de Stadt have given me a nice drawing showing three
types of construction:

wood strips with a gap of around 1 3/4" between the strips, filled
with polyurethane foam, and covered with a plywood skin.

Solid plywood panels glued together and shaped

foam with a epoxy and glass fibre skin.

any of the above seems ok (apart from perhaps the plywood one may be a
bit heavy?)

but is it possible ( perhaps the stupid question) to make a rudder the
salme way as my hull ie; western red cedar strips laminated with a
fibreglass and epoxy skin? Its seems pretty tough now my hull is made
and for me it may be easier to make and fit on my rudder stock. It
seems to me it would be at least as strong as a foam rudder, and
almost as light.

BTW, the first construction method doesn't make the rudder shaft
manufactureres (Jefa) squeal with joy.

wow, obviously it was a stupid question. Never mind, I sussed it out
for myself

cheers

On Thu, 06 Apr 2006 13:16:26 +0200, pete wrote:

Well its time to make my rudder, for a tiller steered 34 foot Van de
Stadt. Now Van de Stadt have given me a nice drawing showing three
types of construction:

wood strips with a gap of around 1 3/4" between the strips, filled
with polyurethane foam, and covered with a plywood skin.

Solid plywood panels glued together and shaped

foam with a epoxy and glass fibre skin.

any of the above seems ok (apart from perhaps the plywood one may be a
bit heavy?)

but is it possible ( perhaps the stupid question) to make a rudder the
salme way as my hull ie; western red cedar strips laminated with a
fibreglass and epoxy skin? Its seems pretty tough now my hull is made
and for me it may be easier to make and fit on my rudder stock. It
seems to me it would be at least as strong as a foam rudder, and
almost as light.

BTW, the first construction method doesn't make the rudder shaft
manufactureres (Jefa) squeal with joy.

Thanks for the input folks. The weight / floatability bit isn't
relevant for me as the rudders is not hung on pintles, rather goes
through the hull on bearings. So it won't ride up. Since posting this
I have found that the rudder gets its strength from the spokes welded
to the rudder shaft, and the manufacturers of the shaft explained to
me how to fit a foam core around the spokes and cover it with epoxy
and glass. I quite fancied the idea of a cedar rudder, but in the end
foam is easier

Point taken about sealing the ends. I had a boat with a hollow
fibreglass rudder once and when I took it off for servicing the
bearings,, I found half a gallon of watere sloshing around inside

Pete