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11-09-2013, 11:42 AM
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#1
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TF Site Team/Forum Founder
City: League City, Tx
Vessel Name: Floatsome & Jetsome
Vessel Model: Meridian 411
Join Date: Oct 2007
Posts: 7,332
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Wind/weather and performance(FF)
I have noticed on my multilevel floating condo complete with oxygen tent above, that going against a good breeze along with it's associated chop(bay sea state) can cost me up to 2 knots. I went out yesterday and was traveling against wind and chop but WITH the tide and was doing 17kts(SOG) at my normal power setting. I made a 180 without touching the power and cruised back in at 19kts!!! I have always noticed quite a difference in speed at the same power setting but didn't think too much of it and probably wrote it off as a tidal thing. But I have recently realized this to be the case. My full enclosure(FF calls it the oxygen tent...and I always get a kick out of it) causes some pretty significant drag....sail area.
__________________
Prairie 29...Perkins 4236...Sold
Mainship Pilot 30...Yanmar 4LHA-STP...Sold
Carver 356...T-Cummins 330B...Sold
Meridian 411...T-Cummins 450C
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11-09-2013, 12:34 PM
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#2
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Guru
City: Concrete Washington State
Vessel Name: Willy
Vessel Model: Willard Nomad 30'
Join Date: Oct 2007
Posts: 18,743
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Willy has a reasonably low amount of air drag and it shows. I've never increased power w my 40hp engine to compensate for head wind. The "oxygen tent" types may be a bit different but I suspect most all loss of speed is caused by tide flow.
When the wind gets up to 40 or so w 7' seas I always slow down because of the seas and always maintain plenty of headway. So w a low windage boat this is absolutely not a problem.
__________________
Eric
North Western Washington State USA
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11-09-2013, 12:42 PM
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#3
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Guru
City: Ft Pierce
Vessel Name: Sold
Vessel Model: Was an Albin/PSN 40
Join Date: Oct 2011
Posts: 28,148
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Quote:
Originally Posted by Baker
I have noticed on my multilevel floating condo complete with oxygen tent above, that going against a good breeze along with it's associated chop(bay sea state) can cost me up to 2 knots. I went out yesterday and was traveling against wind and chop but WITH the tide and was doing 17kts(SOG) at my normal power setting. I made a 180 without touching the power and cruised back in at 19kts!!! I have always noticed quite a difference in speed at the same power setting but didn't think too much of it and probably wrote it off as a tidal thing. But I have recently realized this to be the case. My full enclosure(FF calls it the oxygen tent...and I always get a kick out of it) causes some pretty significant drag....sail area.
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not sure if I'm being to nitpicky...but if you notice a 2 knot difference...could there be a 1 knot penalty and a 1 knot gain (like cruising into/with a current?
don't get me wrong...my sportfish definitely had a wind penalty with the hardtop/enclosure...
may want to recheck on a windless/currentless day for a more accurate measure if you care...it's not like you are really gonna change much as the enclosure is nice and your speed at that point won't make a huge difference except maybe for planning or trying to make a destination with low fuel.
when the REAL penalties and wind resistance shows up in ALL boats except subs.. ...is when you are probably slowing down for chop anyway.
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11-09-2013, 12:54 PM
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#4
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Master and Commander
City: Vallejo CA
Vessel Name: Carquinez Coot
Vessel Model: penultimate Seahorse Marine Coot hull #6
Join Date: Sep 2010
Posts: 12,559
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A two-knot difference seems too large. Agree with psneeld that water current could be a factor if measuring speed over ground. Haven't noticed a drop in the Coot's speed with strong headwinds. Perhaps it helps to have a slow, low-profile boat to begin with. Do notice a list, however, with strong beam winds.
__________________
Kar-KEEN-ez Koot
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11-09-2013, 01:00 PM
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#5
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Guru
City: Ft Pierce
Vessel Name: Sold
Vessel Model: Was an Albin/PSN 40
Join Date: Oct 2011
Posts: 28,148
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Oh yeah baby..an enclosure can definitely slow you down 2 knots at high wind and boat speeds...did on my sportfish...
I was just curious about going with/against the wind...whether all penalty or half penalty and half assist.
Sure current is an issue but I'm hoping that issue was already though of.
Boat's like Coot and Willy will probably only see a major wind penalty when it's so strong that the waves are slowing you down even more..
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11-09-2013, 04:07 PM
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#6
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Guru
City: Stuart FL
Vessel Name: Lucky Lucky
Vessel Model: Pacific Mariner 65
Join Date: Aug 2013
Posts: 2,760
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Magic has a big enclosure. Worth every knot it may steal. We are headed south and some mornings have been real cold. Once the sun is up I am in tee shirt and shorts while others without enclosures are in winter coats, scarves, hats and gloves; I'm dead serious. They look sooo cold. And, when it blows hard or rains, I'm snug as the proverbial bug in a rug. To my mind, it's "knot" even worth thinking about.
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11-09-2013, 05:36 PM
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#7
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Senior Member
City: Tokyo, Japan / Tampa, Florida / Washington, Virginia
Vessel Name: Mondai Nai
Vessel Model: Nordhaven 55 - 45
Join Date: Mar 2013
Posts: 328
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Tides and current will effect you. You would be surprised how it even effects you out in open water. I have a full displacement hull with 8.5 kt hull design. When traveling in the Gulf of Mexico I have experienced at 1-2 kt difference depending on head winds and bow seas. I am also starting to understand the currents out there to help me.
Sent from my iPad using Trawler
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11-09-2013, 05:39 PM
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#8
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Guru
City: Ft Pierce
Vessel Name: Sold
Vessel Model: Was an Albin/PSN 40
Join Date: Oct 2011
Posts: 28,148
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Hot - flybridge under bimini or no bimini (no enclosure)
Cold - lower station with bus/diesel heater on
Comfy from NJ to Florida in December....
best part...no $10,000 worth of canvas and vinyl to worry about or keep clean or struggle with zippers as the warmth of day changes...
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11-09-2013, 05:43 PM
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#9
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Guru
City: Stuart FL
Vessel Name: Lucky Lucky
Vessel Model: Pacific Mariner 65
Join Date: Aug 2013
Posts: 2,760
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Quote:
Originally Posted by psneeld
Hot - flybridge under bimini or no bimini (no enclosure)
Cold - lower station with bus/diesel heater on
Comfy from NJ to Florida in December....
best part...no $10,000 worth of canvas and vinyl to worry about or keep clean or struggle with zippers as the warmth of day changes...
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Hmm, your boat photo sure looks like it has an enclosure.
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11-09-2013, 05:46 PM
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#10
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Guru
City: Ft Pierce
Vessel Name: Sold
Vessel Model: Was an Albin/PSN 40
Join Date: Oct 2011
Posts: 28,148
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Quote:
Originally Posted by hmason
Hmm, your boat photo sure looks like it has an enclosure.
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old pic...it was the first thing I trashed...I have also replaces the flybridge privacy curtains with black ABS ...
I HATE canvas....way too expensive, even if you do your own...and I hate worrying about it flapping a bit in a breeze and tearing seams.
Here a month old pic.
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11-09-2013, 06:13 PM
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#11
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Guru
City: Stuart FL
Vessel Name: Lucky Lucky
Vessel Model: Pacific Mariner 65
Join Date: Aug 2013
Posts: 2,760
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Quote:
Originally Posted by psneeld
old pic...it was the first thing I trashed...I have also replaces the flybridge privacy curtains with black ABS ...
I HATE canvas....way too expensive, even if you do your own...and I hate worrying about it flapping a bit in a breeze and tearing seams.
Here a month old pic.
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Our enclosure is made of a material called Stamoid. A tad more expensive than Sunbrella but should last way longer. It is a vinyl type material that hoses right off, won't get moldy or deteriorate. It is double stitched with Goretex. The windows are Strataglass Low E that block UV and have a very slight tint. All zippers are heavy duty nylon, also double stitched with Goretex. It is now at the end of its first year and looks like the day it was installed. I hope I can say the same 5-years from now. Our FB is quite large, and surprisingly, the entire job came in under $8K. The FB does not get a drop of water even in a wind driven downpour. It's almost hard for me to believe.
We are liveaboards and the ability to sit and relax on the FB on a chilly or windy day is like having an extra room.
BTW, on our prior boat, a Grand Banks 36 with a bimini only, I hated snapping on the FB cover only to take it off and fold it up the next morning. The windows on the enclosure are a lot easier. Again, different strokes as they say.
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11-09-2013, 07:50 PM
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#12
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Guru
City: Ft Pierce
Vessel Name: Sold
Vessel Model: Was an Albin/PSN 40
Join Date: Oct 2011
Posts: 28,148
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There's a reason there are so many canvas people out there....wherever I can replace it or avoid it....I will...
having run hundreds of boats, maybe thousands, as a pro skipper...no canvas for me....new materials or not.
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11-09-2013, 07:59 PM
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#13
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Master and Commander
City: Vallejo CA
Vessel Name: Carquinez Coot
Vessel Model: penultimate Seahorse Marine Coot hull #6
Join Date: Sep 2010
Posts: 12,559
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Don't need any canvas (unless you count the sails and dinghy cover.)
__________________
Kar-KEEN-ez Koot
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11-09-2013, 11:46 PM
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#14
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Guru
City: SF Bay Area
Vessel Model: Tollycraft 34' Tri Cabin
Join Date: Feb 2011
Posts: 12,569
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Quote:
Originally Posted by markpierce
Don't need any canvas (unless you count the sails and dinghy cover.)
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Mark - That is obviously your favorite pict!!
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11-10-2013, 05:06 AM
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#15
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Scraping Paint
City: Fort Lauderdale
Vessel Model: CHB 48 Zodiac YL 4.2
Join Date: Oct 2007
Posts: 3,804
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Horsepower / Power in Watts Required to Overcome Air Resistance The horsepower required to overcome air resistance is the speed in miles per hour, cubed, times the frontal area in square feet divided by 150,000
Where:
MPH = Speed in miles per hour FA = Frontal area in square feet HP = Horsepower 150,000 = A conversion constant
And don't forget "tail end" drag ... the suction that creates the station wagon effect.
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11-10-2013, 05:24 AM
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#16
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Guru
Join Date: Oct 2007
Posts: 22,553
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IN FL the noisemaker is usually on to power the air cond. in the sealed Oxygen tent.
Boating in canned air , a new way to enjoy the day!
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11-10-2013, 05:41 AM
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#18
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Guru
City: SF Bay Area
Vessel Model: Tollycraft 34' Tri Cabin
Join Date: Feb 2011
Posts: 12,569
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Quote:
Originally Posted by RickB
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Rick - Interesting, Thanks! - Art
And where does this leave us re Mark's favorite picture?? LOL
An Excerpt from link you provided:
" Within the multi-dimensions of disclosure, it has been argued that there are two distinct properties, or continuums: breadth and depth (Collins & Miller, 1994; Joinson, 2001; Moon, 2000; Spiekermann, Grossklags, & Berendt, 2001; Tidwell & Walther, 2002). Breadth relates to the quantity of information disclosed (both frequency and category), and depth to the quality. Depth can range from surface information, such as demographic data, to more core values, such as sexual fantasies and desires (Altman & Taylor, 1973; Joinson & Paine, 2007). Choosing to disclose different information of varying depth and breadth is based on a number of factors including the environment or situation in which the individual finds themselves and their own personal characteristics."
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11-10-2013, 06:15 AM
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#19
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Guru
Join Date: Oct 2007
Posts: 22,553
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Rick needs to add in all the small stuff , masts , a fence around the deck, dink hanging .
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11-10-2013, 06:19 AM
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#20
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Scraping Paint
City: Fort Lauderdale
Vessel Model: CHB 48 Zodiac YL 4.2
Join Date: Oct 2007
Posts: 3,804
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It's all part of the frontal area. Those who are interested can calculate that area and add it to the total.
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