I was wondering about hull speed. This may seam silly to some, but I have to know. I realize sail boats work on a displacement theroy. Where speed boats work on a planeing theroy (motor boats). Is it posible to break plane in a sail boat (22-25ft boat)? If you placed a ?? h.p. motor on and forced the boat to plane, what would happen? I'm somewhat interested in water skiing behind my sail boat (motored at the time) mainly because I don't have the money to buy both boats right now. Of course a new sail boat comes way before a motor boat. So, with performance in mind but also disregarded, what do you think? Can it be done? And how safe is it? Can I plane based on wind alone? Thank you all.
- Status
Maybe!
If you buy a Macgregor. Otherwise you could not put a large enough engine on a traditional keel boat to make it go that fast.
If you buy a Macgregor. Otherwise you could not put a large enough engine on a traditional keel boat to make it go that fast.
Hull speed considerations.
Kevin, first I have got to say that you are going to get so many varied answers on this question and subject that you'd better just take your eleven aspririn NOW. The first thing to consider is that not all boats will plane. Planing is generally considered to be when the boat achieves more of a sliding-on-top-of-the-water attitude than a going-through-the-water attitude. Let's not get more technical than that on a bulletin board. Very few cruising sailboats will ever truly plane. Mostly they do what we call surfing-- surging ahead of the water for a while, then slowing down to let the water catch up. This is best done well off the wind in a following sea. If you have ever surfed (waves), check out how the boat 'drops in' in those first few seconds-- it gives you a surfing rush! Some multihulls plane. Some VERY light trailerables will plane. I would say the Whitbread 60s do not-- but they surf. Ability to plane is a factor involving hull shape, sail trim, weather conditions, crew nerve, righting moment, and ratios of weight to wetted area, sail area to displacement, and a couple more if I think enough about it. Pretty much everything else that does not plane is known as a 'displacement' boat. These boats sail IN the water, not ON it. The theoretical top speed of a displacement hull is known as hull speed. For the average boat the EASY way to figure this is the square root of the waterline times 1.34. This assumes a .51 or so prismatic coefficient which, in spite of what many people will initially perceive, I could probably show applies to 90 percent of production sailboats out there, thus justifying the seemingly-arbitrary 1.34 figure. The little MacGregor Venture 21 was famous for being a planing boat off the wind (check out the common picture of three guys on a red-hulled one under spinnake leaving a wake like a speedboat). I believe MacGregor did run ads showing a skier behind one (but does this mean something like 15-20 kts??? --scary). After all the boat weighs nothing and is essentially always overcanvassed. This is white-knuckled sailing all the way-- way overdriven, positioned on the wind in order to get the most speed, not safety or comfort. Don't try this at home!! Worse, as pictured in the current Ronstan hardware catalogue, are Australian 18s-- boats with 800-1000 ft of sail on an 18-ft hull (the only design requirement). Of COURSE they plane!!! -duhhhh! But can you take the mother-in-law out for the afternoon on one? Just remember that simply attempting to overdrive a normal displacement hull (like with more motor or with dizzyingly more sail than safe for the weather) is only going to: 1. waste fuel 2. reduce control 3. bang the h*ll out of your rigging 4. make you look like an idiot. The books I would recommend about this are all old but still accurate: Sail Power, c. 1973 Skene's Elements of Yacht Design, c.1937 Offshore, 1955 --all of which are in my library. J Cherubini II Cherubini Art
Kevin, first I have got to say that you are going to get so many varied answers on this question and subject that you'd better just take your eleven aspririn NOW. The first thing to consider is that not all boats will plane. Planing is generally considered to be when the boat achieves more of a sliding-on-top-of-the-water attitude than a going-through-the-water attitude. Let's not get more technical than that on a bulletin board. Very few cruising sailboats will ever truly plane. Mostly they do what we call surfing-- surging ahead of the water for a while, then slowing down to let the water catch up. This is best done well off the wind in a following sea. If you have ever surfed (waves), check out how the boat 'drops in' in those first few seconds-- it gives you a surfing rush! Some multihulls plane. Some VERY light trailerables will plane. I would say the Whitbread 60s do not-- but they surf. Ability to plane is a factor involving hull shape, sail trim, weather conditions, crew nerve, righting moment, and ratios of weight to wetted area, sail area to displacement, and a couple more if I think enough about it. Pretty much everything else that does not plane is known as a 'displacement' boat. These boats sail IN the water, not ON it. The theoretical top speed of a displacement hull is known as hull speed. For the average boat the EASY way to figure this is the square root of the waterline times 1.34. This assumes a .51 or so prismatic coefficient which, in spite of what many people will initially perceive, I could probably show applies to 90 percent of production sailboats out there, thus justifying the seemingly-arbitrary 1.34 figure. The little MacGregor Venture 21 was famous for being a planing boat off the wind (check out the common picture of three guys on a red-hulled one under spinnake leaving a wake like a speedboat). I believe MacGregor did run ads showing a skier behind one (but does this mean something like 15-20 kts??? --scary). After all the boat weighs nothing and is essentially always overcanvassed. This is white-knuckled sailing all the way-- way overdriven, positioned on the wind in order to get the most speed, not safety or comfort. Don't try this at home!! Worse, as pictured in the current Ronstan hardware catalogue, are Australian 18s-- boats with 800-1000 ft of sail on an 18-ft hull (the only design requirement). Of COURSE they plane!!! -duhhhh! But can you take the mother-in-law out for the afternoon on one? Just remember that simply attempting to overdrive a normal displacement hull (like with more motor or with dizzyingly more sail than safe for the weather) is only going to: 1. waste fuel 2. reduce control 3. bang the h*ll out of your rigging 4. make you look like an idiot. The books I would recommend about this are all old but still accurate: Sail Power, c. 1973 Skene's Elements of Yacht Design, c.1937 Offshore, 1955 --all of which are in my library. J Cherubini II Cherubini Art
Semi-planing hulls
Kevin, A J24 has a semi-planing hull and will achieve speeds greater than LOW would normally allow. Actually a Whitbread 60 will plane. I've read accounts of these boats running along at a steady 18 to 20 knots. These boats are very lite for the LOA. Boats that are that lite in relation to sail area are really squirrelly....
Kevin, A J24 has a semi-planing hull and will achieve speeds greater than LOW would normally allow. Actually a Whitbread 60 will plane. I've read accounts of these boats running along at a steady 18 to 20 knots. These boats are very lite for the LOA. Boats that are that lite in relation to sail area are really squirrelly....
Check out the 26X!
Check out the MacGregor 26X. It is what you are looking for. Is is a great sailboat? No. Is it a great powwerboat? No. But it powers better than any other sailboat and sails better than any other powerboat. Click on the related link to go to the web page on the 26X. I am considering one for ddaysailing on the Chesapeake Bay, I have a Catalina 30 now (which is for sale)
Check out the MacGregor 26X. It is what you are looking for. Is is a great sailboat? No. Is it a great powwerboat? No. But it powers better than any other sailboat and sails better than any other powerboat. Click on the related link to go to the web page on the 26X. I am considering one for ddaysailing on the Chesapeake Bay, I have a Catalina 30 now (which is for sale)
I've Towed Skiers...
with a Prindle 18. She weighed 90# soaking wet and was wearing a pair of really wide jump skis. She said we about drowned her before she got up. I cannot imagine a sailboat of any sort being able to get my fat ass up out of the water though.
with a Prindle 18. She weighed 90# soaking wet and was wearing a pair of really wide jump skis. She said we about drowned her before she got up. I cannot imagine a sailboat of any sort being able to get my fat ass up out of the water though.
Rick Webb!
That is not proper talk on this web site (FAT ASS). We now have an acronym for this term and you should refer to it as E.I.F.A. (ever increasing fat ass), which I too can relate too.
That is not proper talk on this web site (FAT ASS). We now have an acronym for this term and you should refer to it as E.I.F.A. (ever increasing fat ass), which I too can relate too.
Mac 26X -May be just the ticket for you
Hi Kevin, I used to own a '96 26X. I had a lot of fun with the boat. They are good for family fun other than sailing. There are a lot of used 26X's out there for sail these days. Should be some good deals. The 98 and later models have better steering and some other improvements. Good Luck, Joe C. in NC PS It did pull me (200 lbs) up on a ski.
Hi Kevin, I used to own a '96 26X. I had a lot of fun with the boat. They are good for family fun other than sailing. There are a lot of used 26X's out there for sail these days. Should be some good deals. The 98 and later models have better steering and some other improvements. Good Luck, Joe C. in NC PS It did pull me (200 lbs) up on a ski.
More sorry than you!
Rick: I was just trying to CYA (cover your ass) <haha>. The only thing that offends me is................................................ More about that LATER.
Rick: I was just trying to CYA (cover your ass) <haha>. The only thing that offends me is................................................ More about that LATER.
Pulling A Skier
Okay, I though you would get speed and lower the skier into the water then slowly release the rope until they are a "safe" distance back. Kind of like dry parasailing. How in the world do you pull a skier from a stand still?
Okay, I though you would get speed and lower the skier into the water then slowly release the rope until they are a "safe" distance back. Kind of like dry parasailing. How in the world do you pull a skier from a stand still?
How To
It was like 20 years ago (I had to rethink that but I guess I am getting old enough to say that) but what I remember is we first tried to gybe around her but she could not keep hold of the line as it dragged her along too slow to get up. What we then did was to take a broke ski bridle and attach the float and a hook to the end of the ski line then sailed by and grabbed the hook and attached it to a bridle that we tied between the corners of the tramp. It was a pretty good jerk when the line came taught. As I think about it now we may also have used a surf board for her to straddle till she got up. It was a long time ago I wish I remember a lot of things from that time period. Then again maybe not.
It was like 20 years ago (I had to rethink that but I guess I am getting old enough to say that) but what I remember is we first tried to gybe around her but she could not keep hold of the line as it dragged her along too slow to get up. What we then did was to take a broke ski bridle and attach the float and a hook to the end of the ski line then sailed by and grabbed the hook and attached it to a bridle that we tied between the corners of the tramp. It was a pretty good jerk when the line came taught. As I think about it now we may also have used a surf board for her to straddle till she got up. It was a long time ago I wish I remember a lot of things from that time period. Then again maybe not.
Steve
Beleive it or not but I have actually been to Rio Vista. We ate dinner at a mexican place right on the main drag there, Maria's I think was the name of the place. Best Mexican I had had since I left Texas. That is one of the reasons for my EIFA.
Beleive it or not but I have actually been to Rio Vista. We ate dinner at a mexican place right on the main drag there, Maria's I think was the name of the place. Best Mexican I had had since I left Texas. That is one of the reasons for my EIFA.
Rick, same problem!
Rick: Yes, it was Maria's. My EIFA has grown from Maria's too. What were you doing in RIO VISTA? I did not think anyone knew we were there let alone going there. PS: we can do this out of the forum steve@sdcsoftware.com
Rick: Yes, it was Maria's. My EIFA has grown from Maria's too. What were you doing in RIO VISTA? I did not think anyone knew we were there let alone going there. PS: we can do this out of the forum steve@sdcsoftware.com
- Status