Cutaway transom or not?
 

On Tue, 23 Jun 2009 12:34:27 -0700 (PDT), Frogwatch
wrote:

YES, I'll start a real flame war here but I am serious about the
question.
HK says a cutaway transom allows the boat to drain if it is swamped,
seems sensible.
The designer of my Tolman says to have a high drywell in front of the
motor on a cutaway to make sure she does NOT fill with water.
A compromise seems to be to have the dry well but also have serious
cockpit drains, not the tiny ones you see on most boats, I mean at
least 6" diameter AND have the cockpit drains with flapper valves made
of thick rubber sheet attached to the transom with SS screws. This
would require the boat be decked with floatation underneath.
I am curious because I am considering in the long term what boat to
build next and am considering a modified 23' Tolman Jumbo with more
deadrise.

Despite loving to poke Mr. Science and Boating in the eye once in a
while, transom cutouts do make some sense depending on the boat
design. And it's not for water flow out the stern either whicih is
probably the dumbest thing I've heard - 2/3rds of the transom is still
in place which creates a water dam forcing water out the remaining 1/3
- which happens to be partially plugged by a engine?

It's more for matching available engines to the boat - 30" shaft
engines aren't a common beast and 25" shaft engines are pretty much
the norm - unless you have a boat like mine which is designed as a
short shaft boat, but has a long shaft engine on a jack plate. It's
about the engineering of applying the power to the hull and making it
go rather than emptying the boat of water in case you are stupid
enough to be out running in weather you shouldn't be running around
in.

Racing sailboats have open sterns, but they are a whole different ball
game - their sterns are entirely open, not partially open.

Use of a splash board or dry well is to keep water out of the boat
when backing down or having water come up over the stern in certain
weather conditions. Most boat companies offer an option for a splash
board - around these parts it's unusual to see an open boat without a
splash board in boats with open transoms.

Brackets are the usual solution for those who want to have full
transoms and outboard power. Brackets have the added feature of
actually lengthening the boat by a foot or so - the old axiom that for
any given horse power, extra length on the boat will create more hull
speed - plus not having the engine cluttering up the stern. The down
side to brackets is that you can, and I've done this on a Fish Hawk
and a Sea Pro, bury the engine halfway up the cowl on a hard back down
and abrupt change of running status from quick to slow. That's always
been the one feature of brackets that I've been a little leery of.

If I were planning on building a boat, I'd probably go with a full
transom and use a bracket rather than poking holes in the transom for
an engine. It also depends on how you plan on powering the boat -
outboard or inboard? It may be a mute question.

Cutaway transom or not?
 

Wizard of Woodstock wrote:
On Tue, 23 Jun 2009 12:34:27 -0700 (PDT), Frogwatch
wrote:

YES, I'll start a real flame war here but I am serious about the
question.
HK says a cutaway transom allows the boat to drain if it is swamped,
seems sensible.
The designer of my Tolman says to have a high drywell in front of the
motor on a cutaway to make sure she does NOT fill with water.
A compromise seems to be to have the dry well but also have serious
cockpit drains, not the tiny ones you see on most boats, I mean at
least 6" diameter AND have the cockpit drains with flapper valves made
of thick rubber sheet attached to the transom with SS screws. This
would require the boat be decked with floatation underneath.
I am curious because I am considering in the long term what boat to
build next and am considering a modified 23' Tolman Jumbo with more
deadrise.

Despite loving to poke Mr. Science and Boating in the eye once in a
while, transom cutouts do make some sense depending on the boat
design. And it's not for water flow out the stern either whicih is
probably the dumbest thing I've heard - 2/3rds of the transom is still
in place which creates a water dam forcing water out the remaining 1/3
- which happens to be partially plugged by a engine?

It's more for matching available engines to the boat - 30" shaft
engines aren't a common beast and 25" shaft engines are pretty much
the norm - unless you have a boat like mine which is designed as a
short shaft boat, but has a long shaft engine on a jack plate. It's
about the engineering of applying the power to the hull and making it
go rather than emptying the boat of water in case you are stupid
enough to be out running in weather you shouldn't be running around
in.

Racing sailboats have open sterns, but they are a whole different ball
game - their sterns are entirely open, not partially open.

Use of a splash board or dry well is to keep water out of the boat
when backing down or having water come up over the stern in certain
weather conditions. Most boat companies offer an option for a splash
board - around these parts it's unusual to see an open boat without a
splash board in boats with open transoms.

Brackets are the usual solution for those who want to have full
transoms and outboard power. Brackets have the added feature of
actually lengthening the boat by a foot or so - the old axiom that for
any given horse power, extra length on the boat will create more hull
speed - plus not having the engine cluttering up the stern. The down
side to brackets is that you can, and I've done this on a Fish Hawk
and a Sea Pro, bury the engine halfway up the cowl on a hard back down
and abrupt change of running status from quick to slow. That's always
been the one feature of brackets that I've been a little leery of.

If I were planning on building a boat, I'd probably go with a full
transom and use a bracket rather than poking holes in the transom for
an engine. It also depends on how you plan on powering the boat -
outboard or inboard? It may be a mute question.


Or...even a moot question, Mr. Grammar.

20", 25" and 30" shafts are "commonly" available for outboard motors.
And if I was interested, Parker would have cut the transom on my
21-footer to 30" instead of 25".

Brackets are fairly *un*common on smaller outboard boats. Part of the
reason is a balance issue.

Cutaway transom or not?
 

On Jun 23, 3:34*pm, Frogwatch wrote:
YES, I'll start a real flame war here but I am serious about the
question.
HK says a cutaway transom allows the boat to drain if it is swamped,
seems sensible.
The designer of my Tolman says to have a high drywell in front of the
motor on a cutaway to make sure she does NOT fill with water.
A compromise seems to be to have the dry well but also have serious
cockpit drains, not the tiny ones you see on most boats, I mean at
least 6" diameter AND have the cockpit drains with flapper valves made
of thick rubber sheet attached to the transom with SS screws. *This
would require the boat be decked with floatation underneath.
I am curious because I am considering in the long term what boat to
build next and am considering a modified 23' Tolman Jumbo with more
deadrise.

Ask Harry this: IF a cut out transom is such a great safety feature,
why in hell does Parker themselves sell a dam to protect against
following seas?

Cutaway transom or not?
 

On Wed, 24 Jun 2009 07:48:56 -0400, Wizard of Woodstock
wrote:

On Tue, 23 Jun 2009 12:34:27 -0700 (PDT), Frogwatch
wrote:

YES, I'll start a real flame war here but I am serious about the
question.
HK says a cutaway transom allows the boat to drain if it is swamped,
seems sensible.
The designer of my Tolman says to have a high drywell in front of the
motor on a cutaway to make sure she does NOT fill with water.
A compromise seems to be to have the dry well but also have serious
cockpit drains, not the tiny ones you see on most boats, I mean at
least 6" diameter AND have the cockpit drains with flapper valves made
of thick rubber sheet attached to the transom with SS screws. This
would require the boat be decked with floatation underneath.
I am curious because I am considering in the long term what boat to
build next and am considering a modified 23' Tolman Jumbo with more
deadrise.

Despite loving to poke Mr. Science and Boating in the eye once in a
while, transom cutouts do make some sense depending on the boat
design. And it's not for water flow out the stern either whicih is
probably the dumbest thing I've heard - 2/3rds of the transom is still
in place which creates a water dam forcing water out the remaining 1/3
- which happens to be partially plugged by a engine?

It's more for matching available engines to the boat - 30" shaft
engines aren't a common beast and 25" shaft engines are pretty much
the norm - unless you have a boat like mine which is designed as a
short shaft boat, but has a long shaft engine on a jack plate. It's
about the engineering of applying the power to the hull and making it
go rather than emptying the boat of water in case you are stupid
enough to be out running in weather you shouldn't be running around
in.

Racing sailboats have open sterns, but they are a whole different ball
game - their sterns are entirely open, not partially open.

Use of a splash board or dry well is to keep water out of the boat
when backing down or having water come up over the stern in certain
weather conditions. Most boat companies offer an option for a splash
board - around these parts it's unusual to see an open boat without a
splash board in boats with open transoms.

Brackets are the usual solution for those who want to have full
transoms and outboard power. Brackets have the added feature of
actually lengthening the boat by a foot or so - the old axiom that for
any given horse power, extra length on the boat will create more hull
speed - plus not having the engine cluttering up the stern. The down
side to brackets is that you can, and I've done this on a Fish Hawk
and a Sea Pro, bury the engine halfway up the cowl on a hard back down
and abrupt change of running status from quick to slow. That's always
been the one feature of brackets that I've been a little leery of.

If I were planning on building a boat, I'd probably go with a full
transom and use a bracket rather than poking holes in the transom for
an engine. It also depends on how you plan on powering the boat -
outboard or inboard? It may be a mute question.

I'm still wondering why Parker makes the 'dam' to go in front of the
transom cutout, if the cutout is such a great design feature. One
would think a Parker owner would answer that question.

If the design were for safety reasons, then it would seem Parker would
do the same on its entire outboard powered lineup. But the 18' and the
23' *don't* have the cutout transom. This would lead me to believe
that the transom design was to accomodate the engine configuration, as
you pointed out above.

Perhaps the purpose of the 'dam' is to keep large fish from jumping
into the boat through the cutout?
--

John H

Cutaway transom or not?
 

On Wed, 24 Jun 2009 05:23:27 -0400, John H
wrote:

On Tue, 23 Jun 2009 20:56:16 -0400, Wayne.B
wrote:

On Tue, 23 Jun 2009 20:30:49 -0400, John H
wrote:

I keep waiting for an explanation as to why Parker developed and sells
the 'transom cutout dam' to keep the water from coming in through the
stern. Wouldn't the damn dam also keep the water from going OUT the
stern?

But if it doesn't come in, it doesn't need to go out...

I suppose there might be a few timidly souls out there, or their
wives, that might be somewhat unnerved by the sight of a wave coming
in through the transom cut out. There's a reason why stern brackets
have become popular on offshore outboards.

I agree. But, why does Parker make the dams if the cutout is such a
great idea?

You'll have to check with our resident Parker expert. :-)

Cutaway transom or not?
 

Vic Smith wrote:
On Wed, 24 Jun 2009 08:13:22 -0700 (PDT), Frogwatch
wrote:


So, we do NOT have an answer. Consider that if I build a boat I have
complete control over how to do it EXCEPT, I will not use a bracket.
I would consider deep transom cutouts on either side or large
scuppers.
Consider, my boat has filled about 9' of rainwater sitting in my yard
when I left the drain plug in. With the small 750 gph pump, it took
over 10 minutes to pump it out. If I had the largest capacity pump I
can get, 3500 gph, it would take nearly 1.5 minutes, a long time, so
some type of scupper seems necessary for the eventuality of getting
her nearly swamped.

Here's a link I posted about a year ago.
Watch the vid (it's not long) and listen to this guy.
I think he knows a lot about it.
I like the one-way transom "doors" solution.
There's a shot of them near the end of the vid.
http://www.boattest.com/VLibrary/vPlay.aspx?ID=1216

--Vic


But...how could a guy who builds top of the line boats have more
knowledge about the subject than the Asshole Fans of Harry who post here?

Cutaway transom or not?
 

On Jun 24, 1:36*pm, Vic Smith wrote:
On Wed, 24 Jun 2009 08:13:22 -0700 (PDT), Frogwatch

wrote:

So, we do NOT have an answer. *Consider that if I build a boat I have
complete control over how to do it EXCEPT, I will not use a bracket.
I would consider deep transom cutouts on either side or large
scuppers.
Consider, my boat has filled about 9' of rainwater sitting in my yard
when I left the drain plug in. *With the small 750 gph pump, it took
over 10 minutes to pump it out. *If I had the largest capacity pump I
can get, 3500 gph, it would take nearly 1.5 minutes, a long time, so
some type of scupper seems necessary for the eventuality of getting
her nearly swamped.

Here's a link I posted about a year ago.
Watch the vid (it's not long) and listen to this guy.
I think he knows a lot about it.
I like the one-way transom "doors" solution.
There's a shot of them near the end of the vid.http://www.boattest.com/VLibrary/vPlay.aspx?ID=1216

--Vic

Again, Harry has stated that Parker offers the dam as an option. If
the cut out transom is so safe, why in hell does Parker offer it at
all? I'd think it would be litigious to offer an option that makes the
boat less safe.

Cutaway transom or not?
 

On Wed, 24 Jun 2009 10:58:11 -0700 (PDT), Loogypicker
wrote:

On Jun 24, 1:36Â*pm, Vic Smith wrote:
On Wed, 24 Jun 2009 08:13:22 -0700 (PDT), Frogwatch

wrote:

So, we do NOT have an answer. Â*Consider that if I build a boat I have
complete control over how to do it EXCEPT, I will not use a bracket.
I would consider deep transom cutouts on either side or large
scuppers.
Consider, my boat has filled about 9' of rainwater sitting in my yard
when I left the drain plug in. Â*With the small 750 gph pump, it took
over 10 minutes to pump it out. Â*If I had the largest capacity pump I
can get, 3500 gph, it would take nearly 1.5 minutes, a long time, so
some type of scupper seems necessary for the eventuality of getting
her nearly swamped.

Here's a link I posted about a year ago.
Watch the vid (it's not long) and listen to this guy.
I think he knows a lot about it.
I like the one-way transom "doors" solution.
There's a shot of them near the end of the vid.http://www.boattest.com/VLibrary/vPlay.aspx?ID=1216

--Vic

Again, Harry has stated that Parker offers the dam as an option. If
the cut out transom is so safe, why in hell does Parker offer it at
all? I'd think it would be litigious to offer an option that makes the
boat less safe.

Assuming you're not just doing your obsessive Harry slagging, I can
think of some reasons a person wants the dam:

1. Boater always on calm water, but wants short shaft OB.
Doesn't like the looks of the empty space at the cutout.
2. Boater on all waters, doesn't care about swamping, because
dry feet is his priority.

Probably missed some.
Why do you care? Are you a boater?

--Vic

Cutaway transom or not?
 

On Wed, 24 Jun 2009 08:16:38 -0700 (PDT), Frogwatch
wrote:

I suspect that open/low transom with a cabin without bridgedeck is a
really bad idea because once you got significant water in the cabin,
you're a goner.

Absolutely right.

Some sort of sturdy cabin closure is also a good idea, perhaps like
the drop boards in a sailboat companionway, with sliding bolts to hold
them in place. You might be able to survive a capsize with something
like that.

Cutaway transom or not?
 

On Jun 24, 2:37*pm, Wayne.B wrote:
On Wed, 24 Jun 2009 08:16:38 -0700 (PDT), Frogwatch

wrote:
I suspect that open/low transom with a cabin without bridgedeck is a
really bad idea because once you got significant water in the cabin,
you're a goner.

Absolutely right. *

Some sort of sturdy cabin closure is also a good idea, perhaps like
the drop boards in a sailboat companionway, with sliding bolts to hold
them in place. * You might be able to survive a capsize with something
like that.

David Pascoe:

http://www.yachtsurvey.com/sinking.htm

Does not like either scuppers or low/no transoms. He prefers
duplicate battery systems and large multiple bilge pumps.