Re: Martha Jane stern-o-matic
This is indeed the Fast Motorsailer concept. Check also Hawkeye and
Sneakeasy (with box keel). All three are described in "Boats with an
Open Mind"
CCW--- Inbolger@yahoogroups.com, "pvanderwaart" <pvanderwaart@...> wrote:
Sneakeasy (with box keel). All three are described in "Boats with an
Open Mind"
CCW--- Inbolger@yahoogroups.com, "pvanderwaart" <pvanderwaart@...> wrote:
>bottom of
> > Replace the aft rocker with a straight run, i.e. the bottom is up at
> > the bow, drops down to midship, and then continues horizontally from
> > there on back. Leave the vertical sides alone eg allowing them to
> > taper in as on the unchanged hull (running clear down to the
> > course).
>
> This is the basic idea of the Fast Motorsailer. That was complicated a
> bit by the box cutwater. The lack of rocker after is not going to be
> good for the sailing characteristics.
>
> Replace the aft rocker with a straight run, i.e. the bottom is up atThis is the basic idea of the Fast Motorsailer. That was complicated a
> the bow, drops down to midship, and then continues horizontally from
> there on back. Leave the vertical sides alone eg allowing them to
> taper in as on the unchanged hull (running clear down to the bottom of
> course).
bit by the box cutwater. The lack of rocker after is not going to be
good for the sailing characteristics.
Hi Mike,
the hull, modified as you suggest, could certainly be gotten on the
plane. PCB has said something like any boat can be made to plane if
enough power is applied. The question is just how much power do you
want to apply (economy?), and how will it handle?
The altered dead straight run aft will make the stern much more
bouyant. This may cause the bow to dip, with problems at lower
speeds. At sub-planing speed the transom may pull a largish stern
wave. Of course the extra bouyancy aft could be countered by a
heavier outboard, andits fuel tankage. At planing speed (whatever
that may be for this hull) it may trim, and handle well enough,
perhaps only requiring some modification to any shoe(s).
Jim Michalak seems to have gone through this exercise for some of
his power boats that seem based on non-planing, highly rockered
sailboat types somewhat similar though smaller than Martha Jane.
Have a look at his "Sow's Ear" hull, and AF4.
He has written a fair bit on the design processes he went through to
acheive the economy, low wake, low planing speed, lightness, etc.
for the AF4. The resultant hull is finely tuned with not much
allowance for leeway in any of the design parameters. This suggests
a lot of theoretical or modeling work should be done before such a
big change is made to a Martha Jane hull.
Would you still require the sail? Once this hull was adjusted to
give the performance you were wondering about it may no longer be
much for sailing. In level trim weather helm may become a big
problem, trimmed down at the bow asks for another set of
difficulties.
I wonder what PCB&F would suggest, and if the performance of a "Fast
Motorsailer" is too degraded to consider powering with a smaller
outboard at transitional and low planing speeds?
cheers
Graeme
the hull, modified as you suggest, could certainly be gotten on the
plane. PCB has said something like any boat can be made to plane if
enough power is applied. The question is just how much power do you
want to apply (economy?), and how will it handle?
The altered dead straight run aft will make the stern much more
bouyant. This may cause the bow to dip, with problems at lower
speeds. At sub-planing speed the transom may pull a largish stern
wave. Of course the extra bouyancy aft could be countered by a
heavier outboard, andits fuel tankage. At planing speed (whatever
that may be for this hull) it may trim, and handle well enough,
perhaps only requiring some modification to any shoe(s).
Jim Michalak seems to have gone through this exercise for some of
his power boats that seem based on non-planing, highly rockered
sailboat types somewhat similar though smaller than Martha Jane.
Have a look at his "Sow's Ear" hull, and AF4.
He has written a fair bit on the design processes he went through to
acheive the economy, low wake, low planing speed, lightness, etc.
for the AF4. The resultant hull is finely tuned with not much
allowance for leeway in any of the design parameters. This suggests
a lot of theoretical or modeling work should be done before such a
big change is made to a Martha Jane hull.
Would you still require the sail? Once this hull was adjusted to
give the performance you were wondering about it may no longer be
much for sailing. In level trim weather helm may become a big
problem, trimmed down at the bow asks for another set of
difficulties.
I wonder what PCB&F would suggest, and if the performance of a "Fast
Motorsailer" is too degraded to consider powering with a smaller
outboard at transitional and low planing speeds?
cheers
Graeme
>--- Inbolger@yahoogroups.com, "Mike" <mkstocks@...> wrote:
>... Take a sailing hull similar to a Martha Jane (rocker fore and
>aft). Replace the aft rocker with a straight run,... Would it
>tend to plane yet make a very small wake at slow speeds?... I'm
>>
>just wondering if it would make a reasonable motoring hull -
>much shorter than Topaz...
The Shivaree is listed as cold molded or lapstrake. Martha Jane is a lee
board sharpie. The Tennessee is a power sharpie 6' x 30'. Not having built
my boat I can not claim much expertise in building, however it would seem
that a sharpie would be faster / simpler to construct than a lapstrake
design. Regardless, I would agree that building to the plan is a better
idea than modifying.
Caloosarat
_____
From:bolger@yahoogroups.com[mailto:bolger@yahoogroups.com] On Behalf Of
Bruce Hallman
Sent: Wednesday, May 24, 2006 4:58 PM
To:bolger@yahoogroups.com
Subject: Re: [bolger] Martha Jane stern-o-matic
board sharpie. The Tennessee is a power sharpie 6' x 30'. Not having built
my boat I can not claim much expertise in building, however it would seem
that a sharpie would be faster / simpler to construct than a lapstrake
design. Regardless, I would agree that building to the plan is a better
idea than modifying.
Caloosarat
_____
From:bolger@yahoogroups.com[mailto:bolger@yahoogroups.com] On Behalf Of
Bruce Hallman
Sent: Wednesday, May 24, 2006 4:58 PM
To:bolger@yahoogroups.com
Subject: Re: [bolger] Martha Jane stern-o-matic
On 5/24/06, Chester Young <chester@...> wrote:
> The description given more closely fits the Tennessee with the exception
to
> the stern rocker.
The Tennessee is relatively narrow, 5 feet, I recall. I would say
that this speculative hull shape seems to more closely match the shape
of a Shivaree18, design 648. Certainly, if you wanted a boat like
this you would be well served to build a proven design like Shivaree,
rather that try to modify an exisitng design.
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On 5/24/06, Chester Young <chester@...> wrote:
that this speculative hull shape seems to more closely match the shape
of a Shivaree18, design 648. Certainly, if you wanted a boat like
this you would be well served to build a proven design like Shivaree,
rather that try to modify an exisitng design.
> The description given more closely fits the Tennessee with the exception toThe Tennessee is relatively narrow, 5 feet, I recall. I would say
> the stern rocker.
that this speculative hull shape seems to more closely match the shape
of a Shivaree18, design 648. Certainly, if you wanted a boat like
this you would be well served to build a proven design like Shivaree,
rather that try to modify an exisitng design.
The description given more closely fits the Tennessee with the exception to
the stern rocker. For some comments on handling, fuel economy, and speed
capability see the postings around the end of April. Mr. Bolger noted that
my data was the first he has been given for a 25hp as the boat was designed
with a 10hp in mind. 10hp would be very suitable but would likely not be
able to plan and thus limit top speed to around 9mph. The Tennessee leaves
little wake at any speed and is much less complex a design than either Topaz
or Sitka. Standing head room is absent within the cabin, but the
construction of the Esther Mae included a hard top over the cockpit. This
feature has been much appreciated already, both for the shade and ability to
carry canvas with windows when chill out.
Caloosarat
_____
From:bolger@yahoogroups.com[mailto:bolger@yahoogroups.com] On Behalf Of
Mike
Sent: Wednesday, May 24, 2006 1:48 PM
To:bolger@yahoogroups.com
Subject: [bolger] Martha Jane stern-o-matic
Hi flotation fans-
I'm wondering if anyone has experimented ala the following.
Take a sailing hull similar to a Martha Jane (rocker fore and aft).
Replace the aft rocker with a straight run, i.e. the bottom is up at
the bow, drops down to midship, and then continues horizontally from
there on back. Leave the vertical sides alone eg allowing them to
taper in as on the unchanged hull (running clear down to the bottom of
course).
Does this seem to be essentially the Sitka/Topaz type hull? Would it
tend to plane yet make a very small wake at slow speeds?
I'm just wondering if it would make a reasonable motoring hull - much
shorter than Topaz.
Thoughts???
Bolger rules!!!
- NO "GO AWAY SPAMMER!" posts!!! Please!
- no cursing, flaming, trolling, spamming, respamming, or flogging dead
horses
- stay on topic, stay on thread, punctuate, no 'Ed, thanks, Fred' posts
- Pls add your comments at the TOP, SIGN your posts, and snip away
- Plans: Mr. Philip C. Bolger, P.O. Box 1209, Gloucester, MA, 01930, Fax:
(978) 282-1349
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the stern rocker. For some comments on handling, fuel economy, and speed
capability see the postings around the end of April. Mr. Bolger noted that
my data was the first he has been given for a 25hp as the boat was designed
with a 10hp in mind. 10hp would be very suitable but would likely not be
able to plan and thus limit top speed to around 9mph. The Tennessee leaves
little wake at any speed and is much less complex a design than either Topaz
or Sitka. Standing head room is absent within the cabin, but the
construction of the Esther Mae included a hard top over the cockpit. This
feature has been much appreciated already, both for the shade and ability to
carry canvas with windows when chill out.
Caloosarat
_____
From:bolger@yahoogroups.com[mailto:bolger@yahoogroups.com] On Behalf Of
Mike
Sent: Wednesday, May 24, 2006 1:48 PM
To:bolger@yahoogroups.com
Subject: [bolger] Martha Jane stern-o-matic
Hi flotation fans-
I'm wondering if anyone has experimented ala the following.
Take a sailing hull similar to a Martha Jane (rocker fore and aft).
Replace the aft rocker with a straight run, i.e. the bottom is up at
the bow, drops down to midship, and then continues horizontally from
there on back. Leave the vertical sides alone eg allowing them to
taper in as on the unchanged hull (running clear down to the bottom of
course).
Does this seem to be essentially the Sitka/Topaz type hull? Would it
tend to plane yet make a very small wake at slow speeds?
I'm just wondering if it would make a reasonable motoring hull - much
shorter than Topaz.
Thoughts???
Bolger rules!!!
- NO "GO AWAY SPAMMER!" posts!!! Please!
- no cursing, flaming, trolling, spamming, respamming, or flogging dead
horses
- stay on topic, stay on thread, punctuate, no 'Ed, thanks, Fred' posts
- Pls add your comments at the TOP, SIGN your posts, and snip away
- Plans: Mr. Philip C. Bolger, P.O. Box 1209, Gloucester, MA, 01930, Fax:
(978) 282-1349
- Unsubscribe:bolger-unsubscribe@yahoogroups.com
- Open discussion:bolger_coffee_lounge-subscribe@yahoogroups.com
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Phil
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Hi flotation fans-
I'm wondering if anyone has experimented ala the following.
Take a sailing hull similar to a Martha Jane (rocker fore and aft).
Replace the aft rocker with a straight run, i.e. the bottom is up at
the bow, drops down to midship, and then continues horizontally from
there on back. Leave the vertical sides alone eg allowing them to
taper in as on the unchanged hull (running clear down to the bottom of
course).
Does this seem to be essentially the Sitka/Topaz type hull? Would it
tend to plane yet make a very small wake at slow speeds?
I'm just wondering if it would make a reasonable motoring hull - much
shorter than Topaz.
Thoughts???
I'm wondering if anyone has experimented ala the following.
Take a sailing hull similar to a Martha Jane (rocker fore and aft).
Replace the aft rocker with a straight run, i.e. the bottom is up at
the bow, drops down to midship, and then continues horizontally from
there on back. Leave the vertical sides alone eg allowing them to
taper in as on the unchanged hull (running clear down to the bottom of
course).
Does this seem to be essentially the Sitka/Topaz type hull? Would it
tend to plane yet make a very small wake at slow speeds?
I'm just wondering if it would make a reasonable motoring hull - much
shorter than Topaz.
Thoughts???