Re: [bolger] Re: fast canoes and slow canoes at slow speed??
On 8/14/07, ANDREW AIREY <andyairey@...> wrote:
rowing in still water with plenty of freeboard in reserve.
I weigh 14 stone, and had no problem sailing my Tortoise in rough
water earlier this summer. (Lee shore sailing, 10kt wind with five
miles of fetch.)
That boat, stout and wide, carries a lot of weight.
>Last week, those three girls weighed 22 stone and 12 pounds total,
>
> what will a tortoise actually carry in still or river
> coditions.I weigh,regrettably,about 18 stone
> cheers
> Andy Airey
rowing in still water with plenty of freeboard in reserve.
I weigh 14 stone, and had no problem sailing my Tortoise in rough
water earlier this summer. (Lee shore sailing, 10kt wind with five
miles of fetch.)
That boat, stout and wide, carries a lot of weight.
what will a tortoise actually carry in still or river
coditions.I weigh,regrettably,about 18 stone
cheers
Andy Airey
Send instant messages to your online friendshttp://uk.messenger.yahoo.com
coditions.I weigh,regrettably,about 18 stone
cheers
Andy Airey
Send instant messages to your online friendshttp://uk.messenger.yahoo.com
On 8/13/07, John Kohnen <jhkohnen@...> wrote:
rowboat. I had mine up at the lake last week. I wish I had a photo
of her happily rowing around carrying three teenagers comfortably, on
waterline, with aplomb. (Even sure and steady with a kid standing
up!)
> At speeds well below "hull speed" the main source of drag is skinWhich explains, in part, why Tortoise is such an excellent little
> friction, so the shorter canoe will be easier to paddle at 1.5-2 mph.
rowboat. I had mine up at the lake last week. I wish I had a photo
of her happily rowing around carrying three teenagers comfortably, on
waterline, with aplomb. (Even sure and steady with a kid standing
up!)
At speeds well below "hull speed" the main source of drag is skin
friction, so the shorter canoe will be easier to paddle at 1.5-2 mph.
friction, so the shorter canoe will be easier to paddle at 1.5-2 mph.
On Sun, 12 Aug 2007 15:57:13 -0700, bill in nc wrote:
> paddlers,
>
> lets assume similar hull shapes for 2 canoes - one 16 feet long and
> the other 12 feet long. the rule of "square root of waterline length "
> would make climbing the bow wave limit the speed of the longer at
> perhaps 4 mph and the 12 foot at maybe 3 1/2 mph??
>
> but what about paddling at 1 1/2 - 2 mph where i like to paddle. does
> the shorter boat take more effort at that speed?? is the shorter boat
> harder to paddle at every speed all other things equal??
--
John <jkohnen@...>
One cat just leads to another. <Ernest Hemingway>
> thanks much to everyone! im getting the picture. 8-)And, for more of the 'picture', here is a screenshot of the KAPER
>
> bill in nc
curve for the Bolger hull shape Cartoon 5, which is within the 'canoe
shape' class of boats.
http://farm2.static.flickr.com/1409/1105447168_67357be7a8_o.png
thanks much to everyone! im getting the picture. 8-)
bill in nc
bill in nc
--- Inbolger@yahoogroups.com, "cecbell" <cecbell@...> wrote:
>
>
>
> --- Inbolger@yahoogroups.com, "bill shamblin" <bshamblin2002@>
> wrote:
> >
> > paddlers,
> >
> > lets assume similar hull shapes for 2 canoes - one 16 feet long
and
> > the other 12 feet long. the rule of "square root of waterline
length "
> > would make climbing the bow wave limit the speed of the longer at
> > perhaps 4 mph and the 12 foot at maybe 3 1/2 mph??
> >
> > but what about paddling at 1 1/2 - 2 mph where i like to paddle.
does
> > the shorter boat take more effort at that speed?? is the shorter
boat
> > harder to paddle at every speed all other things equal??
> >
> > thanks 8-)
> >
> > bill in nc.
> >
>
> As I understand it:
> The short answer is that the 12 ft. canoe will be easier to paddle
up
> until wave resistance becomes an issue. Up to that point frictional
> resistance from the wetted surface dominates and since the 12 ft.
canoe
> has less of it, it has less resistance.
>
> Just for fun I tried putting some numbers to it to see what came
out. I
> ran a more or less typical canoe through a modeling pgm at 16 ft.
and 12
> ft. lengths (same beam--34.5 in.) each carrying about the same
load. At
> 16 ft., the wetted surface was 26.5 sq. ft. At 12 ft it needed to
sink
> lower for the load but was still only 21.25 sq. ft. Calculating the
> KAPER resistance at the speeds you mentioned, say 1.5 kts., the 16
ft
> version had .66 lbs. total resistance, the 12 ft .57 lbs. For the
same
> resistance at this range of speed, the 12 ft. canoe is about a
tenth of
> a knot faster. This small advantage for the 12 ft. canoe holds up
to
> about 3.5 kts. At 4 kts., wave resistance begins to show and the
16 ft
> canoe has slightly less resistance. If you can paddle at 10 - 11
lbs.
> thrust, the 16 ft. canoe is about a half kt. faster, 5.2 - 5.3
kts. vs.
> 4.8 for the 12 ft. canoe. (BTW classic hull speed for a 16 ft.
W.L. is
> 5.4 kts., for 12 ft., 4.6 kts. IMHO at this speed it's time to
put a
> sail on these things and join the Yahoo sailing canoe group.
<grin>) I
> don't know how trustworthy the KAPER calcs. are but these are the
> figures it's giving me for these particular canoes. In any case
it's a
> good indication of what's going on.
>
> Hope that's a help.
> Charles Campbell
>
Hello,
In general the shorter boat will have less surface area (skin area) other things being more or less equal. At slow speeds the surface or skin drag are the greater part of the overall drag. The other main part of the drag experienced by a boat is wave making drag. That is the energy lost building waves and wake. This becomes the large part of the overall drag as you approach nominal hull speed, as you say 3.5 to 4 knots.
This means the shorter boat will usually be easier to maintain at up to about 2.5 knots or about 60% of the nominal hull speed, which is about the speed most recreational kayakers and canoe paddlers go. The longer boat will go faster, but will be more work (slightly) at recreational cruising speeds.
My boat is 13 feet overall and about 11 feet on the waterline. I easily keep up with the 16+foot kayaks which my friends have on a day trip.
JG
----- Original Message ----
From: bill shamblin <bshamblin2002@...>
To:bolger@yahoogroups.com
Sent: Sunday, August 12, 2007 6:57:13 PM
Subject: [bolger] fast canoes and slow canoes at slow speed??
paddlers,
lets assume similar hull shapes for 2 canoes - one 16 feet long and
the other 12 feet long. the rule of "square root of waterline length "
would make climbing the bow wave limit the speed of the longer at
perhaps 4 mph and the 12 foot at maybe 3 1/2 mph??
but what about paddling at 1 1/2 - 2 mph where i like to paddle. does
the shorter boat take more effort at that speed?? is the shorter boat
harder to paddle at every speed all other things equal??
thanks 8-)
bill in nc.
Be smarter than spam. See how smart SpamGuard is at giving junk email the boot with the All-new Yahoo! Mail athttp://mrd.mail.yahoo.com/try_beta?.intl=ca
[Non-text portions of this message have been removed]
In general the shorter boat will have less surface area (skin area) other things being more or less equal. At slow speeds the surface or skin drag are the greater part of the overall drag. The other main part of the drag experienced by a boat is wave making drag. That is the energy lost building waves and wake. This becomes the large part of the overall drag as you approach nominal hull speed, as you say 3.5 to 4 knots.
This means the shorter boat will usually be easier to maintain at up to about 2.5 knots or about 60% of the nominal hull speed, which is about the speed most recreational kayakers and canoe paddlers go. The longer boat will go faster, but will be more work (slightly) at recreational cruising speeds.
My boat is 13 feet overall and about 11 feet on the waterline. I easily keep up with the 16+foot kayaks which my friends have on a day trip.
JG
----- Original Message ----
From: bill shamblin <bshamblin2002@...>
To:bolger@yahoogroups.com
Sent: Sunday, August 12, 2007 6:57:13 PM
Subject: [bolger] fast canoes and slow canoes at slow speed??
paddlers,
lets assume similar hull shapes for 2 canoes - one 16 feet long and
the other 12 feet long. the rule of "square root of waterline length "
would make climbing the bow wave limit the speed of the longer at
perhaps 4 mph and the 12 foot at maybe 3 1/2 mph??
but what about paddling at 1 1/2 - 2 mph where i like to paddle. does
the shorter boat take more effort at that speed?? is the shorter boat
harder to paddle at every speed all other things equal??
thanks 8-)
bill in nc.
Be smarter than spam. See how smart SpamGuard is at giving junk email the boot with the All-new Yahoo! Mail athttp://mrd.mail.yahoo.com/try_beta?.intl=ca
[Non-text portions of this message have been removed]
Bill at that speed I don't think it would matter much.
But if they both have the same beam I think the 16
footer would be easer to keep the speed. But then you
also mix in the wetted area and all that.
In the real world I don't think it would matter much.
I think it would be more up to what one do you want to
build.
You know if you build the longer one you have morw
room to carry a 2nd person and gear.
Also how much boat do you want to carry to the water
from the car?
Blessings Krissie
--- bill shamblin <bshamblin2002@...> wrote:
Choose the right car based on your needs. Check out Yahoo! Autos new Car Finder tool.
http://autos.yahoo.com/carfinder/
But if they both have the same beam I think the 16
footer would be easer to keep the speed. But then you
also mix in the wetted area and all that.
In the real world I don't think it would matter much.
I think it would be more up to what one do you want to
build.
You know if you build the longer one you have morw
room to carry a 2nd person and gear.
Also how much boat do you want to carry to the water
from the car?
Blessings Krissie
--- bill shamblin <bshamblin2002@...> wrote:
> paddlers,____________________________________________________________________________________
>
> lets assume similar hull shapes for 2 canoes - one
> 16 feet long and
> the other 12 feet long. the rule of "square root of
> waterline length "
> would make climbing the bow wave limit the speed of
> the longer at
> perhaps 4 mph and the 12 foot at maybe 3 1/2 mph??
>
> but what about paddling at 1 1/2 - 2 mph where i
> like to paddle. does
> the shorter boat take more effort at that speed??
> is the shorter boat
> harder to paddle at every speed all other things
> equal??
>
> thanks 8-)
>
> bill in nc.
>
>
Choose the right car based on your needs. Check out Yahoo! Autos new Car Finder tool.
http://autos.yahoo.com/carfinder/
--- Inbolger@yahoogroups.com, "bill shamblin" <bshamblin2002@...>
wrote:
The short answer is that the 12 ft. canoe will be easier to paddle up
until wave resistance becomes an issue. Up to that point frictional
resistance from the wetted surface dominates and since the 12 ft. canoe
has less of it, it has less resistance.
Just for fun I tried putting some numbers to it to see what came out. I
ran a more or less typical canoe through a modeling pgm at 16 ft. and 12
ft. lengths (same beam--34.5 in.) each carrying about the same load. At
16 ft., the wetted surface was 26.5 sq. ft. At 12 ft it needed to sink
lower for the load but was still only 21.25 sq. ft. Calculating the
KAPER resistance at the speeds you mentioned, say 1.5 kts., the 16 ft
version had .66 lbs. total resistance, the 12 ft .57 lbs. For the same
resistance at this range of speed, the 12 ft. canoe is about a tenth of
a knot faster. This small advantage for the 12 ft. canoe holds up to
about 3.5 kts. At 4 kts., wave resistance begins to show and the 16 ft
canoe has slightly less resistance. If you can paddle at 10 - 11 lbs.
thrust, the 16 ft. canoe is about a half kt. faster, 5.2 - 5.3 kts. vs.
4.8 for the 12 ft. canoe. (BTW classic hull speed for a 16 ft. W.L. is
5.4 kts., for 12 ft., 4.6 kts. IMHO at this speed it's time to put a
sail on these things and join the Yahoo sailing canoe group. <grin>) I
don't know how trustworthy the KAPER calcs. are but these are the
figures it's giving me for these particular canoes. In any case it's a
good indication of what's going on.
Hope that's a help.
Charles Campbell
wrote:
>As I understand it:
> paddlers,
>
> lets assume similar hull shapes for 2 canoes - one 16 feet long and
> the other 12 feet long. the rule of "square root of waterline length "
> would make climbing the bow wave limit the speed of the longer at
> perhaps 4 mph and the 12 foot at maybe 3 1/2 mph??
>
> but what about paddling at 1 1/2 - 2 mph where i like to paddle. does
> the shorter boat take more effort at that speed?? is the shorter boat
> harder to paddle at every speed all other things equal??
>
> thanks 8-)
>
> bill in nc.
>
The short answer is that the 12 ft. canoe will be easier to paddle up
until wave resistance becomes an issue. Up to that point frictional
resistance from the wetted surface dominates and since the 12 ft. canoe
has less of it, it has less resistance.
Just for fun I tried putting some numbers to it to see what came out. I
ran a more or less typical canoe through a modeling pgm at 16 ft. and 12
ft. lengths (same beam--34.5 in.) each carrying about the same load. At
16 ft., the wetted surface was 26.5 sq. ft. At 12 ft it needed to sink
lower for the load but was still only 21.25 sq. ft. Calculating the
KAPER resistance at the speeds you mentioned, say 1.5 kts., the 16 ft
version had .66 lbs. total resistance, the 12 ft .57 lbs. For the same
resistance at this range of speed, the 12 ft. canoe is about a tenth of
a knot faster. This small advantage for the 12 ft. canoe holds up to
about 3.5 kts. At 4 kts., wave resistance begins to show and the 16 ft
canoe has slightly less resistance. If you can paddle at 10 - 11 lbs.
thrust, the 16 ft. canoe is about a half kt. faster, 5.2 - 5.3 kts. vs.
4.8 for the 12 ft. canoe. (BTW classic hull speed for a 16 ft. W.L. is
5.4 kts., for 12 ft., 4.6 kts. IMHO at this speed it's time to put a
sail on these things and join the Yahoo sailing canoe group. <grin>) I
don't know how trustworthy the KAPER calcs. are but these are the
figures it's giving me for these particular canoes. In any case it's a
good indication of what's going on.
Hope that's a help.
Charles Campbell
paddlers,
lets assume similar hull shapes for 2 canoes - one 16 feet long and
the other 12 feet long. the rule of "square root of waterline length "
would make climbing the bow wave limit the speed of the longer at
perhaps 4 mph and the 12 foot at maybe 3 1/2 mph??
but what about paddling at 1 1/2 - 2 mph where i like to paddle. does
the shorter boat take more effort at that speed?? is the shorter boat
harder to paddle at every speed all other things equal??
thanks 8-)
bill in nc.
lets assume similar hull shapes for 2 canoes - one 16 feet long and
the other 12 feet long. the rule of "square root of waterline length "
would make climbing the bow wave limit the speed of the longer at
perhaps 4 mph and the 12 foot at maybe 3 1/2 mph??
but what about paddling at 1 1/2 - 2 mph where i like to paddle. does
the shorter boat take more effort at that speed?? is the shorter boat
harder to paddle at every speed all other things equal??
thanks 8-)
bill in nc.