Re: [bolger] Proper Bottom Design
Pat-
Bring the bottom up to just above the waterline in a gentle curve and you
should do fine at displacement speeds, not making much fuss unless you try
to go faster. For displacement speed you'd need much less than 25 hp.
"Semi-displacement" speeds appear to me (a total non-naval architect) quite
a bit harder to design for than either displacement or planing, I can't
offer any advice about that area. You're lengthening the GP-16 anyway, so
the displacement you lose by cutting away the bottom profile may be made up
in the extra length. Now you have an excuse to try out Gregg Carlson's free
Hulls program to help you get your boat to float on its lines:
http://www.carlsondesign.com/#Fun_Shareware
Bring the bottom up to just above the waterline in a gentle curve and you
should do fine at displacement speeds, not making much fuss unless you try
to go faster. For displacement speed you'd need much less than 25 hp.
"Semi-displacement" speeds appear to me (a total non-naval architect) quite
a bit harder to design for than either displacement or planing, I can't
offer any advice about that area. You're lengthening the GP-16 anyway, so
the displacement you lose by cutting away the bottom profile may be made up
in the extra length. Now you have an excuse to try out Gregg Carlson's free
Hulls program to help you get your boat to float on its lines:
http://www.carlsondesign.com/#Fun_Shareware
On Mon, 29 Oct 2001 20:39:46 -0000, Pat Pateson wrote:
> Bottom/Stern Design for low HP cruising boat.
>
> I am stilll in the "Waiting to get well enough to build it"
> stage of construction of my GP-16/18. (Non-Bolger, although
> very Bolgeresque. 16' "Brick" ?)
> ...
> I missed the detail about a 50 HP outboard being the
> "Recomended" power.
> ...
> The question is.
> Is my "Perfect Boat" not so "Perfect" after all?
> I would like to power it with a low HP (25 HP max, less is better)
> ...
> I thought I might get some opinions first.
> It would be nice to go faster than 5.5 knots, but maybe
> that is to be.
> I can live with that, but I would like to do so without having
> the wake suck creatures off the bottom, and block my view aft.
> ...
--
John <jkohnen@...>
http://www.boat-links.com/
Distrust any enterprise that requires new clothes.
<Henry David Thoreau>
Michalak AF4. She planes cleanly with the 7.5.
JB
JB
----- Original Message -----
From: <pateson@...>
To: <bolger@yahoogroups.com>
Sent: Tuesday, October 30, 2001 11:44 AM
Subject: [bolger] Re: Proper Bottom Design
| "My light shallow 18'er goes over 10 knots with just 7.5 HP."
|
| That's exactly what I want to hear.
| That performance would be "Great" for me.
| 10 miles every hour. That's a long ways.
| What exactly is the 18'er, and how does the bottom
| (especially the aft run) compare to the a GP-16?
|
| I Have an Old Johnson 15. Best thing about it is that
| it runs fine, and is paid for.
| That's what I want to use on it for some time.
| Maybe play with props to get best MPG.
|
|
| I "Plan" on keeping the displacement down, but then,
| we will be living on this thing for a while.
| Maybe anything "New" we want to take aboard, we have
| to exchange for something "Old", rather than just adding to.
|
| Thanks in advance.
|
| I will get hold of Jim Betts when I get some particurars
| to ask him.
|
| Anybody else that is familiar with GP-16 or similar types
| please chime in.
|
| Good help. thanks folks
|
| btw I have considered adding extensions, but I think I will
| just stretch the whole thing to 18 or maybe even 20 feet.
| I think most of the ones being built are opting for 18' oa.
| (Theoretically it can be make as long as one wants,
| but under 20' would be my choice.)
|
| Pat Patteson
| Molalla, Oregon
|
|
|
| --- In bolger@y..., "John Bell" <jmbell@m...> wrote:
| > One thing about your concerns. Unless you really load it down with
| a
| > lot of stuff, GP-16 is a very shallow boat. I don't think you will
| be
| > pulling a big wake, because the size of the wake is proportional to
| > the size of the hole the boat makes in the water. GP-16 floats its
| > displacement over a large shallow hole, instead of a small deep
| one.
| > A shallow hole in the water will not make large waves like a deep
| one
| > will. For instance compare the wakes made by a jon boat compared to
| a
| > deep vee.
| >
| > Also unless deeply laden, I don't believe you'll be limited to
| > displacement speeds with 25 hp either. My light shallow 18'er goes
| > over 10 knots with just 7.5 HP. The best advice would be check with
| > Betts on his thoughts, though.
| >
| > JB
|
|
|
| Bolger rules!!!
| - no cursing, flaming, trolling, spamming, or flogging dead horses
| - pls take "personals" off-list, stay on topic, and punctuate
| - add your comments at the TOP and SIGN your posts, snip all you like
| - To order plans: Mr. Philip C. Bolger, P.O. Box 1209, Gloucester, MA,
01930, Fax: (978) 282-1349
| - Unsubscribe:bolger-unsubscribe@yahoogroups.com
|
| Your use of Yahoo! Groups is subject tohttp://docs.yahoo.com/info/terms/
|
|
"My light shallow 18'er goes over 10 knots with just 7.5 HP."
That's exactly what I want to hear.
That performance would be "Great" for me.
10 miles every hour. That's a long ways.
What exactly is the 18'er, and how does the bottom
(especially the aft run) compare to the a GP-16?
I Have an Old Johnson 15. Best thing about it is that
it runs fine, and is paid for.
That's what I want to use on it for some time.
Maybe play with props to get best MPG.
I "Plan" on keeping the displacement down, but then,
we will be living on this thing for a while.
Maybe anything "New" we want to take aboard, we have
to exchange for something "Old", rather than just adding to.
Thanks in advance.
I will get hold of Jim Betts when I get some particurars
to ask him.
Anybody else that is familiar with GP-16 or similar types
please chime in.
Good help. thanks folks
btw I have considered adding extensions, but I think I will
just stretch the whole thing to 18 or maybe even 20 feet.
I think most of the ones being built are opting for 18' oa.
(Theoretically it can be make as long as one wants,
but under 20' would be my choice.)
Pat Patteson
Molalla, Oregon
That's exactly what I want to hear.
That performance would be "Great" for me.
10 miles every hour. That's a long ways.
What exactly is the 18'er, and how does the bottom
(especially the aft run) compare to the a GP-16?
I Have an Old Johnson 15. Best thing about it is that
it runs fine, and is paid for.
That's what I want to use on it for some time.
Maybe play with props to get best MPG.
I "Plan" on keeping the displacement down, but then,
we will be living on this thing for a while.
Maybe anything "New" we want to take aboard, we have
to exchange for something "Old", rather than just adding to.
Thanks in advance.
I will get hold of Jim Betts when I get some particurars
to ask him.
Anybody else that is familiar with GP-16 or similar types
please chime in.
Good help. thanks folks
btw I have considered adding extensions, but I think I will
just stretch the whole thing to 18 or maybe even 20 feet.
I think most of the ones being built are opting for 18' oa.
(Theoretically it can be make as long as one wants,
but under 20' would be my choice.)
Pat Patteson
Molalla, Oregon
--- In bolger@y..., "John Bell" <jmbell@m...> wrote:
> One thing about your concerns. Unless you really load it down with
a
> lot of stuff, GP-16 is a very shallow boat. I don't think you will
be
> pulling a big wake, because the size of the wake is proportional to
> the size of the hole the boat makes in the water. GP-16 floats its
> displacement over a large shallow hole, instead of a small deep
one.
> A shallow hole in the water will not make large waves like a deep
one
> will. For instance compare the wakes made by a jon boat compared to
a
> deep vee.
>
> Also unless deeply laden, I don't believe you'll be limited to
> displacement speeds with 25 hp either. My light shallow 18'er goes
> over 10 knots with just 7.5 HP. The best advice would be check with
> Betts on his thoughts, though.
>
> JB
According to the Bateau page, GP-16 is also available with a
vee-bottom. While your draft would increase, it could improve your
wake/hole in the water. Or it might make it worse, as per John Bell.
I'm sure the designer will be able to straighten this question
out. Please post what you find out, the GP-16 is "on my list" - along
with too many others...:-)
vee-bottom. While your draft would increase, it could improve your
wake/hole in the water. Or it might make it worse, as per John Bell.
I'm sure the designer will be able to straighten this question
out. Please post what you find out, the GP-16 is "on my list" - along
with too many others...:-)
--- In bolger@y..., pateson@c... wrote:
> Bottom/Stern Design for low HP cruising boat.
>
> I am stilll in the "Waiting to get well enough to build it"
> stage of construction of my GP-16/18. (Non-Bolger, although
> very Bolgeresque. 16' "Brick" ?)
> For many reasons, but mostly for the "Cool", Landing Craft
> Ramp, I chose it as my "Perfect Boat".
> It is to be the last boat I will have to build that will
> give me as few compromises as I can live with, and be
> comfortable for my Wife and me to spend some time "Cruising"
> some of the local water ways.
>
> Apparetly blinded by "All Things Good" about the boat,
> I missed the detail about a 50 HP outboard being the
> "Recomended" power.
> The cost of a "No Worries" (I want to be enjoying the "Scenery"
> of "Nature", and not that of the "Under Shroud" of some motor)
> 50 HP motor is more than I had planned to spend to build the boat.
> Also, a "Relaxing time" for me, does not involve bouncing
> over crests at 30 MPH wondering what that was that just fell
> out of the Galley cabinet.
{ ... }
>
> Thanks
> Pat Patteson
> Molalla, Oregon
One thing about your concerns. Unless you really load it down with a
lot of stuff, GP-16 is a very shallow boat. I don't think you will be
pulling a big wake, because the size of the wake is proportional to
the size of the hole the boat makes in the water. GP-16 floats its
displacement over a large shallow hole, instead of a small deep one.
A shallow hole in the water will not make large waves like a deep one
will. For instance compare the wakes made by a jon boat compared to a
deep vee.
Also unless deeply laden, I don't believe you'll be limited to
displacement speeds with 25 hp either. My light shallow 18'er goes
over 10 knots with just 7.5 HP. The best advice would be check with
Betts on his thoughts, though.
JB
lot of stuff, GP-16 is a very shallow boat. I don't think you will be
pulling a big wake, because the size of the wake is proportional to
the size of the hole the boat makes in the water. GP-16 floats its
displacement over a large shallow hole, instead of a small deep one.
A shallow hole in the water will not make large waves like a deep one
will. For instance compare the wakes made by a jon boat compared to a
deep vee.
Also unless deeply laden, I don't believe you'll be limited to
displacement speeds with 25 hp either. My light shallow 18'er goes
over 10 knots with just 7.5 HP. The best advice would be check with
Betts on his thoughts, though.
JB
Pat, have you thought about adding transom extensions a la Sneakeasy on
either side of your outboard? That would extend the waterline and
perhaps flatten the wake a bit. You could build them to have a lower
section that floods freely, so your at-rest trim wouldn't be affected.
Just a thought...
David Romasco
-----Original Message-----
From:pateson@...[mailto:pateson@...]
Sent: Monday, October 29, 2001 3:40 PM
To:bolger@yahoogroups.com
Subject: [bolger] Proper Bottom Design
Bottom/Stern Design for low HP cruising boat.
I am stilll in the "Waiting to get well enough to build it"
stage of construction of my GP-16/18. (Non-Bolger, although
very Bolgeresque. 16' "Brick" ?)
For many reasons, but mostly for the "Cool", Landing Craft
Ramp, I chose it as my "Perfect Boat".
It is to be the last boat I will have to build that will
give me as few compromises as I can live with, and be
comfortable for my Wife and me to spend some time "Cruising"
some of the local water ways.
Apparetly blinded by "All Things Good" about the boat,
I missed the detail about a 50 HP outboard being the
"Recomended" power.
The cost of a "No Worries" (I want to be enjoying the "Scenery"
of "Nature", and not that of the "Under Shroud" of some motor)
50 HP motor is more than I had planned to spend to build the boat.
Also, a "Relaxing time" for me, does not involve bouncing
over crests at 30 MPH wondering what that was that just fell
out of the Galley cabinet.
I want to be on the water to enjoy the water, and am really
in No Hurry to "Get" Anywhere, I'm already there.
The boat is totally self contained, and drawing only a few
inches of water, I could either drift, throw out an anchor,
or find a sheltered shore, lower the ramp, and exlplore some
place that few others have been.
(For any of you near the Willamette Valey of Oregon, USA,
there is a wonderful book "Willamette Landings" that chronicles
nearly all of the, now forgotten, Willamette River steam boat
landings. Nice read even if you are not near by.
Forgotten communities.
I would like to visit as many of those as I can, as well as
the many miles, and forgotten places, of the Columbia.)
(Elk City too, John)
The question is.
Is my "Perfect Boat" not so "Perfect" after all?
I would like to power it with a low HP (25 HP max, less is better)
Unfortunatly the design of the bottom is the worst example I
have seen for a "Displacement Boat".
Wateline is about 14 feet, and with the svelt, square, beam of
7 feet, and perfectly flat run, it appears that, at speeds approaching
"Hull Speed" of 5-6 knots, it will make a hole big enough to
slide backward into and sink. (Don't you hate it when that happens?)
See:http://groups.yahoo.com/group/Bolger2/files/GP-16%20%20%28Non-
Bolger%29/GP16-Profile.jpg
That is the picture I found next to "Worst Displacement Design"
in my Nautical Dictionary.
I haven't talked to Jim Betts, the designer, yet, about this
minor problem. I still love the rest of the boat.
Love Is Blind.
I thought I might get some opinions first.
It would be nice to go faster than 5.5 knots, but maybe
that is to be.
I can live with that, but I would like to do so without having
the wake suck creatures off the bottom, and block my view aft.
http://www.hotkey.net.au/~robruce/is Bruce Robert's
Nice GP-16 page. He is one of the first builders, and
it appears he has made a Very Nice job of it.
"Compromises, Compromisess, Always Compromises"
"There Is No 'Perfect Boat'."
Thanks
Pat Patteson
Molalla, Oregon
Yahoo! Groups Sponsor
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Bolger rules!!!
- no cursing, flaming, trolling, spamming, or flogging dead horses
- pls take "personals" off-list, stay on topic, and punctuate
- add your comments at the TOP and SIGN your posts, snip all you like
- To order plans: Mr. Philip C. Bolger, P.O. Box 1209, Gloucester, MA,
01930, Fax: (978) 282-1349
- Unsubscribe:bolger-unsubscribe@yahoogroups.com
Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service
<http://docs.yahoo.com/info/terms/> .
[Non-text portions of this message have been removed]
either side of your outboard? That would extend the waterline and
perhaps flatten the wake a bit. You could build them to have a lower
section that floods freely, so your at-rest trim wouldn't be affected.
Just a thought...
David Romasco
-----Original Message-----
From:pateson@...[mailto:pateson@...]
Sent: Monday, October 29, 2001 3:40 PM
To:bolger@yahoogroups.com
Subject: [bolger] Proper Bottom Design
Bottom/Stern Design for low HP cruising boat.
I am stilll in the "Waiting to get well enough to build it"
stage of construction of my GP-16/18. (Non-Bolger, although
very Bolgeresque. 16' "Brick" ?)
For many reasons, but mostly for the "Cool", Landing Craft
Ramp, I chose it as my "Perfect Boat".
It is to be the last boat I will have to build that will
give me as few compromises as I can live with, and be
comfortable for my Wife and me to spend some time "Cruising"
some of the local water ways.
Apparetly blinded by "All Things Good" about the boat,
I missed the detail about a 50 HP outboard being the
"Recomended" power.
The cost of a "No Worries" (I want to be enjoying the "Scenery"
of "Nature", and not that of the "Under Shroud" of some motor)
50 HP motor is more than I had planned to spend to build the boat.
Also, a "Relaxing time" for me, does not involve bouncing
over crests at 30 MPH wondering what that was that just fell
out of the Galley cabinet.
I want to be on the water to enjoy the water, and am really
in No Hurry to "Get" Anywhere, I'm already there.
The boat is totally self contained, and drawing only a few
inches of water, I could either drift, throw out an anchor,
or find a sheltered shore, lower the ramp, and exlplore some
place that few others have been.
(For any of you near the Willamette Valey of Oregon, USA,
there is a wonderful book "Willamette Landings" that chronicles
nearly all of the, now forgotten, Willamette River steam boat
landings. Nice read even if you are not near by.
Forgotten communities.
I would like to visit as many of those as I can, as well as
the many miles, and forgotten places, of the Columbia.)
(Elk City too, John)
The question is.
Is my "Perfect Boat" not so "Perfect" after all?
I would like to power it with a low HP (25 HP max, less is better)
Unfortunatly the design of the bottom is the worst example I
have seen for a "Displacement Boat".
Wateline is about 14 feet, and with the svelt, square, beam of
7 feet, and perfectly flat run, it appears that, at speeds approaching
"Hull Speed" of 5-6 knots, it will make a hole big enough to
slide backward into and sink. (Don't you hate it when that happens?)
See:http://groups.yahoo.com/group/Bolger2/files/GP-16%20%20%28Non-
Bolger%29/GP16-Profile.jpg
That is the picture I found next to "Worst Displacement Design"
in my Nautical Dictionary.
I haven't talked to Jim Betts, the designer, yet, about this
minor problem. I still love the rest of the boat.
Love Is Blind.
I thought I might get some opinions first.
It would be nice to go faster than 5.5 knots, but maybe
that is to be.
I can live with that, but I would like to do so without having
the wake suck creatures off the bottom, and block my view aft.
http://www.hotkey.net.au/~robruce/is Bruce Robert's
Nice GP-16 page. He is one of the first builders, and
it appears he has made a Very Nice job of it.
"Compromises, Compromisess, Always Compromises"
"There Is No 'Perfect Boat'."
Thanks
Pat Patteson
Molalla, Oregon
Yahoo! Groups Sponsor
ADVERTISEMENT
<http://rd.yahoo.com/M=213858.1650662.3186813.1261774/D=egroupweb/S=1705
065791:HM/A=763352/R=0/*http://www.classmates.com/index.tf?s=5085>
<http://us.adserver.yahoo.com/l?M=213858.1650662.3186813.1261774/D=egrou
pmail/S=1705065791:HM/A=763352/rand=916718664>
Bolger rules!!!
- no cursing, flaming, trolling, spamming, or flogging dead horses
- pls take "personals" off-list, stay on topic, and punctuate
- add your comments at the TOP and SIGN your posts, snip all you like
- To order plans: Mr. Philip C. Bolger, P.O. Box 1209, Gloucester, MA,
01930, Fax: (978) 282-1349
- Unsubscribe:bolger-unsubscribe@yahoogroups.com
Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service
<http://docs.yahoo.com/info/terms/> .
[Non-text portions of this message have been removed]
Bottom/Stern Design for low HP cruising boat.
I am stilll in the "Waiting to get well enough to build it"
stage of construction of my GP-16/18. (Non-Bolger, although
very Bolgeresque. 16' "Brick" ?)
For many reasons, but mostly for the "Cool", Landing Craft
Ramp, I chose it as my "Perfect Boat".
It is to be the last boat I will have to build that will
give me as few compromises as I can live with, and be
comfortable for my Wife and me to spend some time "Cruising"
some of the local water ways.
Apparetly blinded by "All Things Good" about the boat,
I missed the detail about a 50 HP outboard being the
"Recomended" power.
The cost of a "No Worries" (I want to be enjoying the "Scenery"
of "Nature", and not that of the "Under Shroud" of some motor)
50 HP motor is more than I had planned to spend to build the boat.
Also, a "Relaxing time" for me, does not involve bouncing
over crests at 30 MPH wondering what that was that just fell
out of the Galley cabinet.
I want to be on the water to enjoy the water, and am really
in No Hurry to "Get" Anywhere, I'm already there.
The boat is totally self contained, and drawing only a few
inches of water, I could either drift, throw out an anchor,
or find a sheltered shore, lower the ramp, and exlplore some
place that few others have been.
(For any of you near the Willamette Valey of Oregon, USA,
there is a wonderful book "Willamette Landings" that chronicles
nearly all of the, now forgotten, Willamette River steam boat
landings. Nice read even if you are not near by.
Forgotten communities.
I would like to visit as many of those as I can, as well as
the many miles, and forgotten places, of the Columbia.)
(Elk City too, John)
The question is.
Is my "Perfect Boat" not so "Perfect" after all?
I would like to power it with a low HP (25 HP max, less is better)
Unfortunatly the design of the bottom is the worst example I
have seen for a "Displacement Boat".
Wateline is about 14 feet, and with the svelt, square, beam of
7 feet, and perfectly flat run, it appears that, at speeds approaching
"Hull Speed" of 5-6 knots, it will make a hole big enough to
slide backward into and sink. (Don't you hate it when that happens?)
See:http://groups.yahoo.com/group/Bolger2/files/GP-16%20%20%28Non-
Bolger%29/GP16-Profile.jpg
That is the picture I found next to "Worst Displacement Design"
in my Nautical Dictionary.
I haven't talked to Jim Betts, the designer, yet, about this
minor problem. I still love the rest of the boat.
Love Is Blind.
I thought I might get some opinions first.
It would be nice to go faster than 5.5 knots, but maybe
that is to be.
I can live with that, but I would like to do so without having
the wake suck creatures off the bottom, and block my view aft.
http://www.hotkey.net.au/~robruce/is Bruce Robert's
Nice GP-16 page. He is one of the first builders, and
it appears he has made a Very Nice job of it.
"Compromises, Compromisess, Always Compromises"
"There Is No 'Perfect Boat'."
Thanks
Pat Patteson
Molalla, Oregon
I am stilll in the "Waiting to get well enough to build it"
stage of construction of my GP-16/18. (Non-Bolger, although
very Bolgeresque. 16' "Brick" ?)
For many reasons, but mostly for the "Cool", Landing Craft
Ramp, I chose it as my "Perfect Boat".
It is to be the last boat I will have to build that will
give me as few compromises as I can live with, and be
comfortable for my Wife and me to spend some time "Cruising"
some of the local water ways.
Apparetly blinded by "All Things Good" about the boat,
I missed the detail about a 50 HP outboard being the
"Recomended" power.
The cost of a "No Worries" (I want to be enjoying the "Scenery"
of "Nature", and not that of the "Under Shroud" of some motor)
50 HP motor is more than I had planned to spend to build the boat.
Also, a "Relaxing time" for me, does not involve bouncing
over crests at 30 MPH wondering what that was that just fell
out of the Galley cabinet.
I want to be on the water to enjoy the water, and am really
in No Hurry to "Get" Anywhere, I'm already there.
The boat is totally self contained, and drawing only a few
inches of water, I could either drift, throw out an anchor,
or find a sheltered shore, lower the ramp, and exlplore some
place that few others have been.
(For any of you near the Willamette Valey of Oregon, USA,
there is a wonderful book "Willamette Landings" that chronicles
nearly all of the, now forgotten, Willamette River steam boat
landings. Nice read even if you are not near by.
Forgotten communities.
I would like to visit as many of those as I can, as well as
the many miles, and forgotten places, of the Columbia.)
(Elk City too, John)
The question is.
Is my "Perfect Boat" not so "Perfect" after all?
I would like to power it with a low HP (25 HP max, less is better)
Unfortunatly the design of the bottom is the worst example I
have seen for a "Displacement Boat".
Wateline is about 14 feet, and with the svelt, square, beam of
7 feet, and perfectly flat run, it appears that, at speeds approaching
"Hull Speed" of 5-6 knots, it will make a hole big enough to
slide backward into and sink. (Don't you hate it when that happens?)
See:http://groups.yahoo.com/group/Bolger2/files/GP-16%20%20%28Non-
Bolger%29/GP16-Profile.jpg
That is the picture I found next to "Worst Displacement Design"
in my Nautical Dictionary.
I haven't talked to Jim Betts, the designer, yet, about this
minor problem. I still love the rest of the boat.
Love Is Blind.
I thought I might get some opinions first.
It would be nice to go faster than 5.5 knots, but maybe
that is to be.
I can live with that, but I would like to do so without having
the wake suck creatures off the bottom, and block my view aft.
http://www.hotkey.net.au/~robruce/is Bruce Robert's
Nice GP-16 page. He is one of the first builders, and
it appears he has made a Very Nice job of it.
"Compromises, Compromisess, Always Compromises"
"There Is No 'Perfect Boat'."
Thanks
Pat Patteson
Molalla, Oregon