Re: [bolger] Re: Transom Sterner v Double Enders
Great points
As regards this:
"Top speed is a function of length of water line."
Obviously top speed isn't the same as ease of speed,
adn even that top speed stuff is just a
generalisation, it only holds when all the hulls are
identical to those from which the formulla was modelled
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As regards this:
"Top speed is a function of length of water line."
Obviously top speed isn't the same as ease of speed,
adn even that top speed stuff is just a
generalisation, it only holds when all the hulls are
identical to those from which the formulla was modelled
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I have heard it said, but haven't really looked into
it, because who wants a canoe with a transom, and most
of the other boats I have built or considered have
them. I think it has somethiing to do with how the
wake is flatened. My concerns are more practical.
You need to have some load carrying ability for the
aft placement of the cockpit. This also helps keep the
stern up in shallow water, and at speed. You don't
want to make the boat to deep aft, to impede turning.
And you want a big rudder for lift going to windward,
so you have to look out for your lateral plane. I am
talking here exclusively about canoe type hulls, not
those that have two ends, but the rear is fat and flat
below the WL as though it had a transom.
---timothy@...wrote:
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--- In bolger@y..., PseudoDion3@a... wrote:<BR>
contribute <BR>
Hi Dennis,<BR>
<BR>
Who has suggested that? I haven't heard any broad
statements like <BR>
that one, though most boats these days -are- 'transom'
boats.<BR>
<BR>
--Timothy<BR>
<BR>
<BR>
</tt>
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it, because who wants a canoe with a transom, and most
of the other boats I have built or considered have
them. I think it has somethiing to do with how the
wake is flatened. My concerns are more practical.
You need to have some load carrying ability for the
aft placement of the cockpit. This also helps keep the
stern up in shallow water, and at speed. You don't
want to make the boat to deep aft, to impede turning.
And you want a big rudder for lift going to windward,
so you have to look out for your lateral plane. I am
talking here exclusively about canoe type hulls, not
those that have two ends, but the rear is fat and flat
below the WL as though it had a transom.
---timothy@...wrote:
<HR>
<html><body>
<tt>
--- In bolger@y..., PseudoDion3@a... wrote:<BR>
> It has been suggested that transom sterned boatsoffer or <BR>
contribute <BR>
> to seaworthiness and speed in a vessel incomparison to double <BR>
> enders. Would anyone know if this is true and whyit would be so?<BR>
> <BR><BR>
> Thanks,<BR>
> <BR>
> Dennis Marshall<BR>
Hi Dennis,<BR>
<BR>
Who has suggested that? I haven't heard any broad
statements like <BR>
that one, though most boats these days -are- 'transom'
boats.<BR>
<BR>
--Timothy<BR>
<BR>
<BR>
</tt>
<br>
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Bolger rules!!!<BR>
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- pls take "personals" off-list, stay on
topic, and punctuate<BR>
- add your comments at the TOP and SIGN your posts,
snip all you like<BR>
- To order plans: Mr. Philip C. Bolger, P.O. Box 1209,
Gloucester, MA, 01930, Fax: (978) 282-1349<BR>
- Unsubscribe:
bolger-unsubscribe@yahoogroups.com</tt>
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HAve been wondering about just this question in comparing a double
ended swampscott dory to a "tombstone" sterned one. Wouldn't a double
ender weathercock more than transom sterned? Which is better fo
pulling?
Doug
ended swampscott dory to a "tombstone" sterned one. Wouldn't a double
ender weathercock more than transom sterned? Which is better fo
pulling?
Doug
--- In bolger@y..., wmrpage@a... wrote:
> In a message dated 11/19/01 1:36:29 PM Central Standard Time,
> PseudoDion3@a... writes:
>
>
> > It has been suggested that transom sterned boats offer or
contribute
> > to seaworthiness and speed in a vessel in comparison to double
> > enders. Would anyone know if this is true and why it would be so?
> >
> >
>
> All things being "equal" (which they can't be), a transom sterned
boat will
> pick up a greater righting moment when heeled and have flatter
buttocks that
> a canoe sterned boat. This gives the transom sterned boat greater
sail
> carrying power and more speed potential for a given waterline
length.
>
> There once was, perhaps still is, a fair amount of anectodal opinion
on the
> superior seaworthiness of canoe sterned vessels (the cult of Colin
Archer,
> etc.). I'm skeptical. "Seaworthiness" is a pretty subjective and
elastic
> quality, but change in stern shape, by itself, would not, I think,
confer
> that quality on a design not already possessing it. The cockpit on a
canoe
> sterned boat is almost invariably further forward and generally
smaller than
> one on a transom sterned boat of comparable length. This would be
good for
> seakeeping in rough weather, but any transom sterned boat could be
given a
> similar cockpit configuration if the designer, builder or owner were
willing
> to sacrifice the greater accomodation space a transom sterned boat
can
> provide.
>
> Ive also seen the argument advanced that canoe sterned boats are
easier to
> build. Perhaps there was something in this in days of old, when men
were
> iron, ships were wood with sawn planks landed on chiseled rabbets in
solid
> oak deadwoods. I think it a pretty moot issue today, given modern
small boat
> construction techniques.
>
> I think the "real" and only necessary justification for canoe
sterned boats
> is that they can be so darn pretty!
>
> (all this falls into the category of "conventional wisdom" and is
without any
> warranties, express or implied)
>
> Ciao for Niao,
>
> Bill in MN
>
>
> [Non-text portions of this message have been removed]
In a message dated 11/19/01 1:36:29 PM Central Standard Time,
PseudoDion3@...writes:
pick up a greater righting moment when heeled and have flatter buttocks that
a canoe sterned boat. This gives the transom sterned boat greater sail
carrying power and more speed potential for a given waterline length.
There once was, perhaps still is, a fair amount of anectodal opinion on the
superior seaworthiness of canoe sterned vessels (the cult of Colin Archer,
etc.). I'm skeptical. "Seaworthiness" is a pretty subjective and elastic
quality, but change in stern shape, by itself, would not, I think, confer
that quality on a design not already possessing it. The cockpit on a canoe
sterned boat is almost invariably further forward and generally smaller than
one on a transom sterned boat of comparable length. This would be good for
seakeeping in rough weather, but any transom sterned boat could be given a
similar cockpit configuration if the designer, builder or owner were willing
to sacrifice the greater accomodation space a transom sterned boat can
provide.
Ive also seen the argument advanced that canoe sterned boats are easier to
build. Perhaps there was something in this in days of old, when men were
iron, ships were wood with sawn planks landed on chiseled rabbets in solid
oak deadwoods. I think it a pretty moot issue today, given modern small boat
construction techniques.
I think the "real" and only necessary justification for canoe sterned boats
is that they can be so darn pretty!
(all this falls into the category of "conventional wisdom" and is without any
warranties, express or implied)
Ciao for Niao,
Bill in MN
[Non-text portions of this message have been removed]
PseudoDion3@...writes:
> It has been suggested that transom sterned boats offer or contributeAll things being "equal" (which they can't be), a transom sterned boat will
> to seaworthiness and speed in a vessel in comparison to double
> enders. Would anyone know if this is true and why it would be so?
>
>
pick up a greater righting moment when heeled and have flatter buttocks that
a canoe sterned boat. This gives the transom sterned boat greater sail
carrying power and more speed potential for a given waterline length.
There once was, perhaps still is, a fair amount of anectodal opinion on the
superior seaworthiness of canoe sterned vessels (the cult of Colin Archer,
etc.). I'm skeptical. "Seaworthiness" is a pretty subjective and elastic
quality, but change in stern shape, by itself, would not, I think, confer
that quality on a design not already possessing it. The cockpit on a canoe
sterned boat is almost invariably further forward and generally smaller than
one on a transom sterned boat of comparable length. This would be good for
seakeeping in rough weather, but any transom sterned boat could be given a
similar cockpit configuration if the designer, builder or owner were willing
to sacrifice the greater accomodation space a transom sterned boat can
provide.
Ive also seen the argument advanced that canoe sterned boats are easier to
build. Perhaps there was something in this in days of old, when men were
iron, ships were wood with sawn planks landed on chiseled rabbets in solid
oak deadwoods. I think it a pretty moot issue today, given modern small boat
construction techniques.
I think the "real" and only necessary justification for canoe sterned boats
is that they can be so darn pretty!
(all this falls into the category of "conventional wisdom" and is without any
warranties, express or implied)
Ciao for Niao,
Bill in MN
[Non-text portions of this message have been removed]
--- In bolger@y..., timothy@e... wrote:
behind you will tend to push a transom stern to one side or the other.
This can cause a broach.
A double ender's stern will tend to float up and the path of the boat
will tend to stay straight, or at least straighter than a square
stern.
Top speed is a function of length of water line. How fast a boat
gets to top speed is a function of how much it weighs (more mass =
slower acceleration) and the amount of wetted surface ( friction with
the water ).
I have never read that a pointy stern has anything to do with speed
other than you will end up a longer water line per amount of
living/cockpit space than you would with a square stern . . . but
that is stretching it.
> --- In bolger@y..., PseudoDion3@a... wrote:If you get in to heavy waves you will find that a wave coming up
> > It has been suggested that transom sterned boats offer or
> contribute
> > to seaworthiness and speed in a vessel in comparison to double
> > enders. Would anyone know if this is true and why it would be so?
behind you will tend to push a transom stern to one side or the other.
This can cause a broach.
A double ender's stern will tend to float up and the path of the boat
will tend to stay straight, or at least straighter than a square
stern.
Top speed is a function of length of water line. How fast a boat
gets to top speed is a function of how much it weighs (more mass =
slower acceleration) and the amount of wetted surface ( friction with
the water ).
I have never read that a pointy stern has anything to do with speed
other than you will end up a longer water line per amount of
living/cockpit space than you would with a square stern . . . but
that is stretching it.
--- In bolger@y..., PseudoDion3@a... wrote:
Who has suggested that? I haven't heard any broad statements like
that one, though most boats these days -are- 'transom' boats.
--Timothy
> It has been suggested that transom sterned boats offer orcontribute
> to seaworthiness and speed in a vessel in comparison to doubleHi Dennis,
> enders. Would anyone know if this is true and why it would be so?
>
> Thanks,
>
> Dennis Marshall
Who has suggested that? I haven't heard any broad statements like
that one, though most boats these days -are- 'transom' boats.
--Timothy
It has been suggested that transom sterned boats offer or contribute
to seaworthiness and speed in a vessel in comparison to double
enders. Would anyone know if this is true and why it would be so?
Thanks,
Dennis Marshall
to seaworthiness and speed in a vessel in comparison to double
enders. Would anyone know if this is true and why it would be so?
Thanks,
Dennis Marshall