Re: [bolger] Re: RX-1 Single-Screw Race Boat/ California Lobsterboat Info ?
Hi Howard,
Thanks for the information .2500KG (5500lbs approx.) would probably be about right for the displacement of the California Lobster Boat, therefore those speeds you quoted with a 150 HP diesel seem to be well within my requirements. I know the "Cagliostro" design well, but she's just that bit too large for me. 20 Knots is fast enough, especially when the going gets rough!
Hugo Tyson, Launceston, Tasmania, Australia.
Howard Stephenson <stephensonhw@...> wrote:
Hi Hugo,
I was estimating 2500 KG, not lbs. but did not try to work out the
design displacement from the drawing. And I only allowed a 10 deg.
deadrise when using Bailey's formula. Average deadrise along the
planing surface is probably 15deg. or more.
In his late 60s or early 70s book, Richard Hartley devoted two pages
to keels and shaft logs on planing hulls. He recommends a fairly
shallow keel or skeg -- his type D, about as deep as the bottom of
the prop and finishing well forward of it -- for speeds from 25 to 35
mph. Anything larger would risk cavitation. For speeds from 15 to 25
mph he shows a keel that is a fraction deeper than the prop and
extending further aft towards it, but definitely not under it.
For the type D keel, he says that it would be 11" deep on his 17' and
19' designs, and " these boats are at least a mile per hour faster
for every 2" that is cut off the depth of the keel."
There's no doubt in my mind this Bolger design would be as good as
you could get in a head sea. A similar design is Cagliostro, from 30-
Odd Boats. It has slightly less deadrise (diminishing to none at the
transom) but still has the extreme warp to the planing surface. It's
41' x 12', with no displacement indicated. It could cruise at 15 kt
with twin 130 hp Perkins diesels. It used a skeg just like Hartley's
type D, but of course with no prop or rudder directly aft of it. PCB
says "I did several boats on variations of this model, all slightly
disappointing in speed and all highly praised for comfort on rough
water."
But, having owned a boat that could not be trusted in a following sea
(an old 16' deHavilland boat with a deep forefoot, a shallow stern
and a heavy 70hp outboard), I would always prefer security downhill
over comfort uphill.
Howard
Gold Coast
Australia
Thanks for the information .2500KG (5500lbs approx.) would probably be about right for the displacement of the California Lobster Boat, therefore those speeds you quoted with a 150 HP diesel seem to be well within my requirements. I know the "Cagliostro" design well, but she's just that bit too large for me. 20 Knots is fast enough, especially when the going gets rough!
Hugo Tyson, Launceston, Tasmania, Australia.
Howard Stephenson <stephensonhw@...> wrote:
Hi Hugo,
I was estimating 2500 KG, not lbs. but did not try to work out the
design displacement from the drawing. And I only allowed a 10 deg.
deadrise when using Bailey's formula. Average deadrise along the
planing surface is probably 15deg. or more.
In his late 60s or early 70s book, Richard Hartley devoted two pages
to keels and shaft logs on planing hulls. He recommends a fairly
shallow keel or skeg -- his type D, about as deep as the bottom of
the prop and finishing well forward of it -- for speeds from 25 to 35
mph. Anything larger would risk cavitation. For speeds from 15 to 25
mph he shows a keel that is a fraction deeper than the prop and
extending further aft towards it, but definitely not under it.
For the type D keel, he says that it would be 11" deep on his 17' and
19' designs, and " these boats are at least a mile per hour faster
for every 2" that is cut off the depth of the keel."
There's no doubt in my mind this Bolger design would be as good as
you could get in a head sea. A similar design is Cagliostro, from 30-
Odd Boats. It has slightly less deadrise (diminishing to none at the
transom) but still has the extreme warp to the planing surface. It's
41' x 12', with no displacement indicated. It could cruise at 15 kt
with twin 130 hp Perkins diesels. It used a skeg just like Hartley's
type D, but of course with no prop or rudder directly aft of it. PCB
says "I did several boats on variations of this model, all slightly
disappointing in speed and all highly praised for comfort on rough
water."
But, having owned a boat that could not be trusted in a following sea
(an old 16' deHavilland boat with a deep forefoot, a shallow stern
and a heavy 70hp outboard), I would always prefer security downhill
over comfort uphill.
Howard
Gold Coast
Australia
--- Inbolger@yahoogroups.com, Hugo Tyson <hhetyson@y...> wrote:
> Hi Howard,
>
> I would assume the California Lobsterboat would probably displace
closer to 3500+ lbs, so speeds would be a bit down on what you
surmised. I'm thinking that about 180HP @ 3400-3600 Rpm maybe would
yield about 18 Knots top speed, which is totally OK, with a fast,
continuous cruising speed of about 14 knots. The hull as shown in the
plans in "The Folding Schooner....." may not be so good in a
following sea, but what boat is at its best in these conditions
anyway?! I've just written a letter to Mr Bolger asking him about
this design and if it would benefit from the addition of a full
keel/skeg and what sort of size diesel it would require for
the 'Moderate" speed(No more than 20 Kts. Max.!) he talks about,
instead of the 450+ C.I.D Gasoline engine that was to guarantee 25+
Knots in any conditions. My main enthusiasim for this design was
that this would be a good sort of boat for when you had to punch
into a head sea that she would be a bit more forgiving than a fuller
bowed boat
> and you'd be able to get home a bit more quickly!
>
> I'm still waiting for Phil to finish the plans for "Silver Blaze"
( a 26' x 6'6" Torpedo-sterned Fast Runabout) before I can even
seriously consider building another boat. But I'm still of the
opinion that I might build the "California Lobsterboat" someday, if
the inclusion of a keel/skeg will not degrade the performance too
much and hopefully will improve her behaviour in the following sea
conditions you so fear.....as we all do? !!
>
> Hugo Tyson, Launcseton, Tasmania, Australia.
> Howard Stephenson <stephensonhw@a...> wrote:
> Hi Hugo,
>
> If you assume a displacement of 2500 Kg and 150 bhp, according to
> Keith's rule, you could expect the Calif. Lobsterboat to reach 19
kt
> or, according to Crouch's rule, 25 Kt. Frank Bailey's rule
indicates
> about 21 Kt.
Bolger rules!!!
- no cursing, flaming, trolling, spamming, 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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[Non-text portions of this message have been removed]
Hi Hugo,
I was estimating 2500 KG, not lbs. but did not try to work out the
design displacement from the drawing. And I only allowed a 10 deg.
deadrise when using Bailey's formula. Average deadrise along the
planing surface is probably 15deg. or more.
In his late 60s or early 70s book, Richard Hartley devoted two pages
to keels and shaft logs on planing hulls. He recommends a fairly
shallow keel or skeg -- his type D, about as deep as the bottom of
the prop and finishing well forward of it -- for speeds from 25 to 35
mph. Anything larger would risk cavitation. For speeds from 15 to 25
mph he shows a keel that is a fraction deeper than the prop and
extending further aft towards it, but definitely not under it.
For the type D keel, he says that it would be 11" deep on his 17' and
19' designs, and " these boats are at least a mile per hour faster
for every 2" that is cut off the depth of the keel."
There's no doubt in my mind this Bolger design would be as good as
you could get in a head sea. A similar design is Cagliostro, from 30-
Odd Boats. It has slightly less deadrise (diminishing to none at the
transom) but still has the extreme warp to the planing surface. It's
41' x 12', with no displacement indicated. It could cruise at 15 kt
with twin 130 hp Perkins diesels. It used a skeg just like Hartley's
type D, but of course with no prop or rudder directly aft of it. PCB
says "I did several boats on variations of this model, all slightly
disappointing in speed and all highly praised for comfort on rough
water."
But, having owned a boat that could not be trusted in a following sea
(an old 16' deHavilland boat with a deep forefoot, a shallow stern
and a heavy 70hp outboard), I would always prefer security downhill
over comfort uphill.
Howard
Gold Coast
Australia
I was estimating 2500 KG, not lbs. but did not try to work out the
design displacement from the drawing. And I only allowed a 10 deg.
deadrise when using Bailey's formula. Average deadrise along the
planing surface is probably 15deg. or more.
In his late 60s or early 70s book, Richard Hartley devoted two pages
to keels and shaft logs on planing hulls. He recommends a fairly
shallow keel or skeg -- his type D, about as deep as the bottom of
the prop and finishing well forward of it -- for speeds from 25 to 35
mph. Anything larger would risk cavitation. For speeds from 15 to 25
mph he shows a keel that is a fraction deeper than the prop and
extending further aft towards it, but definitely not under it.
For the type D keel, he says that it would be 11" deep on his 17' and
19' designs, and " these boats are at least a mile per hour faster
for every 2" that is cut off the depth of the keel."
There's no doubt in my mind this Bolger design would be as good as
you could get in a head sea. A similar design is Cagliostro, from 30-
Odd Boats. It has slightly less deadrise (diminishing to none at the
transom) but still has the extreme warp to the planing surface. It's
41' x 12', with no displacement indicated. It could cruise at 15 kt
with twin 130 hp Perkins diesels. It used a skeg just like Hartley's
type D, but of course with no prop or rudder directly aft of it. PCB
says "I did several boats on variations of this model, all slightly
disappointing in speed and all highly praised for comfort on rough
water."
But, having owned a boat that could not be trusted in a following sea
(an old 16' deHavilland boat with a deep forefoot, a shallow stern
and a heavy 70hp outboard), I would always prefer security downhill
over comfort uphill.
Howard
Gold Coast
Australia
--- Inbolger@yahoogroups.com, Hugo Tyson <hhetyson@y...> wrote:
> Hi Howard,
>
> I would assume the California Lobsterboat would probably displace
closer to 3500+ lbs, so speeds would be a bit down on what you
surmised. I'm thinking that about 180HP @ 3400-3600 Rpm maybe would
yield about 18 Knots top speed, which is totally OK, with a fast,
continuous cruising speed of about 14 knots. The hull as shown in the
plans in "The Folding Schooner....." may not be so good in a
following sea, but what boat is at its best in these conditions
anyway?! I've just written a letter to Mr Bolger asking him about
this design and if it would benefit from the addition of a full
keel/skeg and what sort of size diesel it would require for
the 'Moderate" speed(No more than 20 Kts. Max.!) he talks about,
instead of the 450+ C.I.D Gasoline engine that was to guarantee 25+
Knots in any conditions. My main enthusiasim for this design was
that this would be a good sort of boat for when you had to punch
into a head sea that she would be a bit more forgiving than a fuller
bowed boat
> and you'd be able to get home a bit more quickly!
>
> I'm still waiting for Phil to finish the plans for "Silver Blaze"
( a 26' x 6'6" Torpedo-sterned Fast Runabout) before I can even
seriously consider building another boat. But I'm still of the
opinion that I might build the "California Lobsterboat" someday, if
the inclusion of a keel/skeg will not degrade the performance too
much and hopefully will improve her behaviour in the following sea
conditions you so fear.....as we all do? !!
>
> Hugo Tyson, Launcseton, Tasmania, Australia.
> Howard Stephenson <stephensonhw@a...> wrote:
> Hi Hugo,
>
> If you assume a displacement of 2500 Kg and 150 bhp, according to
> Keith's rule, you could expect the Calif. Lobsterboat to reach 19
kt
> or, according to Crouch's rule, 25 Kt. Frank Bailey's rule
indicates
> about 21 Kt.
Hi Howard,
I would assume the California Lobsterboat would probably displace closer to 3500+ lbs, so speeds would be a bit down on what you surmised. I'm thinking that about 180HP @ 3400-3600 Rpm maybe would yield about 18 Knots top speed, which is totally OK, with a fast, continuous cruising speed of about 14 knots. The hull as shown in the plans in "The Folding Schooner....." may not be so good in a following sea, but what boat is at its best in these conditions anyway?! I've just written a letter to Mr Bolger asking him about this design and if it would benefit from the addition of a full keel/skeg and what sort of size diesel it would require for the 'Moderate" speed(No more than 20 Kts. Max.!) he talks about, instead of the 450+ C.I.D Gasoline engine that was to guarantee 25+ Knots in any conditions. My main enthusiasim for this design was that this would be a good sort of boat for when you had to punch into a head sea that she would be a bit more forgiving than a fuller bowed boat
and you'd be able to get home a bit more quickly!
I'm still waiting for Phil to finish the plans for "Silver Blaze" ( a 26' x 6'6" Torpedo-sterned Fast Runabout) before I can even seriously consider building another boat. But I'm still of the opinion that I might build the "California Lobsterboat" someday, if the inclusion of a keel/skeg will not degrade the performance too much and hopefully will improve her behaviour in the following sea conditions you so fear.....as we all do? !!
Hugo Tyson, Launcseton, Tasmania, Australia.
Howard Stephenson <stephensonhw@...> wrote:
Hi Hugo,
If you assume a displacement of 2500 Kg and 150 bhp, according to
Keith's rule, you could expect the Calif. Lobsterboat to reach 19 kt
or, according to Crouch's rule, 25 Kt. Frank Bailey's rule indicates
about 21 Kt.
I am not convinced that a hull of this shape is any good in a
following sea. The deep forefoot could dig into the back of the wave
in front and the buoyant, shallow stern would be lifted by the slope
of the wave behind it. The stern would then try to overtake the bow
and the boat would broach. A deep skeg or perhaps a large rudder
might help downhill control.
PCB used to draw a lot of these hulls with a heavily warped planing
surface. I think he was trying to prove that an early mentor, Lindsay
Lord, was wrong in his view that planing hulls should have straight
parallel buttock lines. PCB's recent planing hulls e.g. Shivaree,
have abandoned these warped bottoms.
Howard
I would assume the California Lobsterboat would probably displace closer to 3500+ lbs, so speeds would be a bit down on what you surmised. I'm thinking that about 180HP @ 3400-3600 Rpm maybe would yield about 18 Knots top speed, which is totally OK, with a fast, continuous cruising speed of about 14 knots. The hull as shown in the plans in "The Folding Schooner....." may not be so good in a following sea, but what boat is at its best in these conditions anyway?! I've just written a letter to Mr Bolger asking him about this design and if it would benefit from the addition of a full keel/skeg and what sort of size diesel it would require for the 'Moderate" speed(No more than 20 Kts. Max.!) he talks about, instead of the 450+ C.I.D Gasoline engine that was to guarantee 25+ Knots in any conditions. My main enthusiasim for this design was that this would be a good sort of boat for when you had to punch into a head sea that she would be a bit more forgiving than a fuller bowed boat
and you'd be able to get home a bit more quickly!
I'm still waiting for Phil to finish the plans for "Silver Blaze" ( a 26' x 6'6" Torpedo-sterned Fast Runabout) before I can even seriously consider building another boat. But I'm still of the opinion that I might build the "California Lobsterboat" someday, if the inclusion of a keel/skeg will not degrade the performance too much and hopefully will improve her behaviour in the following sea conditions you so fear.....as we all do? !!
Hugo Tyson, Launcseton, Tasmania, Australia.
Howard Stephenson <stephensonhw@...> wrote:
Hi Hugo,
If you assume a displacement of 2500 Kg and 150 bhp, according to
Keith's rule, you could expect the Calif. Lobsterboat to reach 19 kt
or, according to Crouch's rule, 25 Kt. Frank Bailey's rule indicates
about 21 Kt.
I am not convinced that a hull of this shape is any good in a
following sea. The deep forefoot could dig into the back of the wave
in front and the buoyant, shallow stern would be lifted by the slope
of the wave behind it. The stern would then try to overtake the bow
and the boat would broach. A deep skeg or perhaps a large rudder
might help downhill control.
PCB used to draw a lot of these hulls with a heavily warped planing
surface. I think he was trying to prove that an early mentor, Lindsay
Lord, was wrong in his view that planing hulls should have straight
parallel buttock lines. PCB's recent planing hulls e.g. Shivaree,
have abandoned these warped bottoms.
Howard
--- Inbolger@yahoogroups.com, "hhetyson" <hhetyson@y...> wrote:
> Has anybody got any information or pictures other than the small
> picture in the "Folding Schooner" book, pg.175(Chapter 29) of
> Bolger's "RX-1" race boat that apparentley won the Single-screw
> division of the "Round Long Island" and "Miami-Nassau" Boat races
in
> 1961.I'm quite interested in gaining more info about this boat.
> The "California Lobsterboat" ,Chapter 29 of the "Folding Schooner"
> Book appeals to me as a very seaworthy type of boat suited to the
> conditions we get here in Tasmania. As Bolger states it would suit
> moderate power very well with good economy. By this I assume he
> means a Diesel engine of no more than 200 HP, hopefully not much
> more than 100 HP with a top speed of around 16 Knots and less
> weight than a 45o C.I.D. Gasoline engine.?
>
> Hugo Tyson, Launceston, Tasmania, Australia.
Bolger rules!!!
- no cursing, flaming, trolling, spamming, 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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To visit your group on the web, go to:
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---------------------------------
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[Non-text portions of this message have been removed]
Hi Hugo,
If you assume a displacement of 2500 Kg and 150 bhp, according to
Keith's rule, you could expect the Calif. Lobsterboat to reach 19 kt
or, according to Crouch's rule, 25 Kt. Frank Bailey's rule indicates
about 21 Kt.
I am not convinced that a hull of this shape is any good in a
following sea. The deep forefoot could dig into the back of the wave
in front and the buoyant, shallow stern would be lifted by the slope
of the wave behind it. The stern would then try to overtake the bow
and the boat would broach. A deep skeg or perhaps a large rudder
might help downhill control.
PCB used to draw a lot of these hulls with a heavily warped planing
surface. I think he was trying to prove that an early mentor, Lindsay
Lord, was wrong in his view that planing hulls should have straight
parallel buttock lines. PCB's recent planing hulls e.g. Shivaree,
have abandoned these warped bottoms.
Howard
If you assume a displacement of 2500 Kg and 150 bhp, according to
Keith's rule, you could expect the Calif. Lobsterboat to reach 19 kt
or, according to Crouch's rule, 25 Kt. Frank Bailey's rule indicates
about 21 Kt.
I am not convinced that a hull of this shape is any good in a
following sea. The deep forefoot could dig into the back of the wave
in front and the buoyant, shallow stern would be lifted by the slope
of the wave behind it. The stern would then try to overtake the bow
and the boat would broach. A deep skeg or perhaps a large rudder
might help downhill control.
PCB used to draw a lot of these hulls with a heavily warped planing
surface. I think he was trying to prove that an early mentor, Lindsay
Lord, was wrong in his view that planing hulls should have straight
parallel buttock lines. PCB's recent planing hulls e.g. Shivaree,
have abandoned these warped bottoms.
Howard
--- Inbolger@yahoogroups.com, "hhetyson" <hhetyson@y...> wrote:
> Has anybody got any information or pictures other than the small
> picture in the "Folding Schooner" book, pg.175(Chapter 29) of
> Bolger's "RX-1" race boat that apparentley won the Single-screw
> division of the "Round Long Island" and "Miami-Nassau" Boat races
in
> 1961.I'm quite interested in gaining more info about this boat.
> The "California Lobsterboat" ,Chapter 29 of the "Folding Schooner"
> Book appeals to me as a very seaworthy type of boat suited to the
> conditions we get here in Tasmania. As Bolger states it would suit
> moderate power very well with good economy. By this I assume he
> means a Diesel engine of no more than 200 HP, hopefully not much
> more than 100 HP with a top speed of around 16 Knots and less
> weight than a 45o C.I.D. Gasoline engine.?
>
> Hugo Tyson, Launceston, Tasmania, Australia.
Has anybody got any information or pictures other than the small
picture in the "Folding Schooner" book, pg.175(Chapter 29) of
Bolger's "RX-1" race boat that apparentley won the Single-screw
division of the "Round Long Island" and "Miami-Nassau" Boat races in
1961.I'm quite interested in gaining more info about this boat.
The "California Lobsterboat" ,Chapter 29 of the "Folding Schooner"
Book appeals to me as a very seaworthy type of boat suited to the
conditions we get here in Tasmania. As Bolger states it would suit
moderate power very well with good economy. By this I assume he
means a Diesel engine of no more than 200 HP, hopefully not much
more than 100 HP with a top speed of around 16 Knots and less
weight than a 45o C.I.D. Gasoline engine.?
Hugo Tyson, Launceston, Tasmania, Australia.
picture in the "Folding Schooner" book, pg.175(Chapter 29) of
Bolger's "RX-1" race boat that apparentley won the Single-screw
division of the "Round Long Island" and "Miami-Nassau" Boat races in
1961.I'm quite interested in gaining more info about this boat.
The "California Lobsterboat" ,Chapter 29 of the "Folding Schooner"
Book appeals to me as a very seaworthy type of boat suited to the
conditions we get here in Tasmania. As Bolger states it would suit
moderate power very well with good economy. By this I assume he
means a Diesel engine of no more than 200 HP, hopefully not much
more than 100 HP with a top speed of around 16 Knots and less
weight than a 45o C.I.D. Gasoline engine.?
Hugo Tyson, Launceston, Tasmania, Australia.