Shack
10-12-2009, 09:55 PM
I'm looking for stories or opinions about bowsprits and their effects during heavy weather (high sea states). Does anyone have experience with bow sprits getting buried in waves and causing damage to a vessel?
View Full Version : Bow sprit in high seas.
jalmberg
10-12-2009, 10:15 PM
I've never heard of such a thing, but I guess that is an argument for the spar-style bowsprit, as opposed to a platform-type. It's hard to imagine a spar-type breaking by a wave, but I suppose a platform-type could take quite a pounding.
-- John
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Check out my blog: http://unlikelyboatbuilder.com
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-- John
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Check out my blog: http://unlikelyboatbuilder.com
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
gonzo
10-13-2009, 09:01 AM
I have been submerged more than once working out in the bowsprit. There isn't usually problems with the boat but with crewmembers getting washed off.
Omeron
10-13-2009, 09:08 AM
If you are burying your bowsprit in solid water, you are probably shipping green water on your decks as well. If that is the case, the sprit may be further down on your list of worries!
gonzo
10-13-2009, 09:09 AM
Not for the bowman
ancient kayaker
10-13-2009, 11:52 AM
Is there a benefit in having a bowsprit in such conditions? For example, ability to carry sail further forward.
Shack
10-13-2009, 12:13 PM
Two boats bury their bows. One with and one without a bow spirit. How much slower is the recovery by the boat with bow sprit versus the one without?
sharpii2
10-13-2009, 12:47 PM
Two boats bury their bows. One with and one without a bow spirit. How much slower is the recovery by the boat with bow sprit versus the one without?
Depends on the bow design.
Many boats without bow sprits have pinched bows.
This is no accident. The pinched bow is often to extend the bow forward, so the bowsprit is not needed.
Boats that have bowsprits usually have fuller, more buoyant bows.
Depends on the bow design.
Many boats without bow sprits have pinched bows.
This is no accident. The pinched bow is often to extend the bow forward, so the bowsprit is not needed.
Boats that have bowsprits usually have fuller, more buoyant bows.
sharpii2
10-13-2009, 12:54 PM
Is there a benefit in having a bowsprit in such conditions? For example, ability to carry sail further forward.
Often there is.
With long keels, the Center of Lateral Resistence (CLR), not to be confused with the Center of Lateral Area (CLA), often ends up quite far forward.
This is very likely to be the case with full length keels that are level and have no downward slope aft.
Comercial sailing ships had to contend with draft as an issue, so were forced to have level long keels.
You see long bowsprits on just about all of them.
Often there is.
With long keels, the Center of Lateral Resistence (CLR), not to be confused with the Center of Lateral Area (CLA), often ends up quite far forward.
This is very likely to be the case with full length keels that are level and have no downward slope aft.
Comercial sailing ships had to contend with draft as an issue, so were forced to have level long keels.
You see long bowsprits on just about all of them.
jalmberg
10-13-2009, 01:47 PM
Two boats bury their bows. One with and one without a bow spirit. How much slower is the recovery by the boat with bow sprit versus the one without?
Assuming a well designed boat, negligible.
Assuming a well designed boat, negligible.
Shack
10-13-2009, 02:15 PM
Sharpii2. (and Jalmberg)
Just for the purpose of discussion, let's isolate the effects of the bow sprit and assume identical bows. How much difference could one reasonably expect?
Just for the purpose of discussion, let's isolate the effects of the bow sprit and assume identical bows. How much difference could one reasonably expect?
jalmberg
10-13-2009, 02:30 PM
Sharpii2. (and Jalmberg)
Just for the purpose of discussion, let's isolate the effects of the bow sprit and assume identical bows. How much difference could one reasonably expect?
Let's assume this Ingrid somehow dug her bowsprit underwater and didn't pitch pole, that probably means her foredeck is underwater too. The resistance of the bowsprit is trivial compared to the upward force of the buoyancy of the bow and the downward leverage being exerted by the weight in the stern. (Not to mention the lofting effect of your prayers.)
http://sailboatforsale.org/pictures/listings/26_16.jpg
The difference would not be zero, of course, but I doubt you'd notice the difference.
A better strategy is to heave to and avoid the scenario altogether!
-- John
Just for the purpose of discussion, let's isolate the effects of the bow sprit and assume identical bows. How much difference could one reasonably expect?
Let's assume this Ingrid somehow dug her bowsprit underwater and didn't pitch pole, that probably means her foredeck is underwater too. The resistance of the bowsprit is trivial compared to the upward force of the buoyancy of the bow and the downward leverage being exerted by the weight in the stern. (Not to mention the lofting effect of your prayers.)
http://sailboatforsale.org/pictures/listings/26_16.jpg
The difference would not be zero, of course, but I doubt you'd notice the difference.
A better strategy is to heave to and avoid the scenario altogether!
-- John
MikeJohns
10-13-2009, 05:32 PM
I'm looking for stories or opinions about bowsprits and their effects during heavy weather (high sea states). Does anyone have experience with bow sprits getting buried in waves and causing damage to a vessel?
Yes I have lots of experience offshore with bowsprits and I like them for several reasons and anchor handling is a huge plus.
They have a damping effect on the pitching too. As the bowsprit enters the water it's travelling fast and throws up a lot of spray the pitch slows, stops and the bow recovers but slower than it entered so there is a greater slamming resistance and a slower recovery. The boom is stayed and it will not break off unless the stays break and they should be sized and attached accordingly.
If you look to the working boats of sail and their design rules of thumb you'll get a good idea of robust bowsprit design since the loss would have been catastrophic.
It's very common to ship green water as the sounding reduces and the waves get steeper and closer together .
Yes I have lots of experience offshore with bowsprits and I like them for several reasons and anchor handling is a huge plus.
They have a damping effect on the pitching too. As the bowsprit enters the water it's travelling fast and throws up a lot of spray the pitch slows, stops and the bow recovers but slower than it entered so there is a greater slamming resistance and a slower recovery. The boom is stayed and it will not break off unless the stays break and they should be sized and attached accordingly.
If you look to the working boats of sail and their design rules of thumb you'll get a good idea of robust bowsprit design since the loss would have been catastrophic.
It's very common to ship green water as the sounding reduces and the waves get steeper and closer together .
capt vimes
10-15-2009, 04:31 AM
i do not want to have my forestay mounted to the bowsprit.... sail a blister, gennacker or whatover from it - yes - but the forestay i like to have securely mounted to the hull....
apart from that, i am with mike...
apart from that, i am with mike...
gonzo
10-15-2009, 07:21 AM
Bowsprits have their own stay. There is a forestay attached to the bowstem or close to it
Shack
10-17-2009, 06:58 PM
MikeJohns,
Thanks for your reply. I think that was most of what I was looking for. I have heard of criticism of bow sprits because of the way they might submerge.
Sounds like an appropriately constructed and stayed sprit shouldn't have major issues in shorter period, high waves. ...if not much more than a no-sprit equiped bow.
Thanks
Thanks for your reply. I think that was most of what I was looking for. I have heard of criticism of bow sprits because of the way they might submerge.
Sounds like an appropriately constructed and stayed sprit shouldn't have major issues in shorter period, high waves. ...if not much more than a no-sprit equiped bow.
Thanks
Perm Stress
10-21-2009, 03:40 PM
I could remember a couple of stories from close sailing buddies:
1) stainless pipe structure bowsprit, (~32ft boat) with anchor and additional forestay out on it, but walking platform itself made of wood, fastened with screws holding it from BELOW. Wood carried off by wave several times in several seasons of sailing the Baltic and North sea. As owner explained, this easily detachable design of platform was intentional. No damage to actual boat made.
2) Wooden platform bowsprit on 54ft boat, wood structural. Two anchors and main forestay out on it. A 3d successive wave carried it off when sailing out of Brest. Mast was saved from falling down, one anchor lost overboard, one retrieved. Deep scratches (some down to iron strengthening in ferrocement hull).
...
1) stainless pipe structure bowsprit, (~32ft boat) with anchor and additional forestay out on it, but walking platform itself made of wood, fastened with screws holding it from BELOW. Wood carried off by wave several times in several seasons of sailing the Baltic and North sea. As owner explained, this easily detachable design of platform was intentional. No damage to actual boat made.
2) Wooden platform bowsprit on 54ft boat, wood structural. Two anchors and main forestay out on it. A 3d successive wave carried it off when sailing out of Brest. Mast was saved from falling down, one anchor lost overboard, one retrieved. Deep scratches (some down to iron strengthening in ferrocement hull).
...
BeauVrolyk
10-21-2009, 07:50 PM
I would hold that there are a number of advantages to bow-sprits, but that modern boats probably don't need them, except down wind. Long long ago boats were quite heavy and had tremendous drag due to being slack bilged and long keeled. Given the drag, one needed a BIG sail plan to move the boat, so there was a bow sprit and a long over hanging boom. While these boats are beautiful to look at, they are a bear to sail, I've sailed them all my life having grown up on a gaff cutter which was guilty of all of the above.
If one does the obviously correct thing, from a design point of view, and makes the boat of modern materials and builds it light, then there's no need for the massive sail area of yore and the bowsprit and overhanging boom disappear. (Consider how small the sails are on a 20 or 30 square meter boat) The only reason that one has a bow sprit today is to allow you to set a great deal of sail area on a reach or run without the difficulty of a spinnaker pole. If you had a big crew and no racing rules to deal with, you'd obviously us a spinnaker pole rather than a sprit because it's better in every way - especially on a run. IMHO.
All of that said, a boat with a sprit looks lovely and the thing is really quite good to tie the anchor line to.
With regard to the water damaging the sprit, this shouldn't ever happen. The loads that are put on the sprit by the sails are tens of times larger than the load that could be put on it by the water. The forces on the jib stay could be well in excess of 70,000 pounds on a mid-sized boat, you'd have to be moving the sprit through the water pretty darned fast to come close to that load. So, I'd suggest that you not worry about it.
I would strongly suggest that you think hard about a lighter boat if you think you actually need a sprit, unless you a nostalgic old fart like me who just likes the way they look.
If one does the obviously correct thing, from a design point of view, and makes the boat of modern materials and builds it light, then there's no need for the massive sail area of yore and the bowsprit and overhanging boom disappear. (Consider how small the sails are on a 20 or 30 square meter boat) The only reason that one has a bow sprit today is to allow you to set a great deal of sail area on a reach or run without the difficulty of a spinnaker pole. If you had a big crew and no racing rules to deal with, you'd obviously us a spinnaker pole rather than a sprit because it's better in every way - especially on a run. IMHO.
All of that said, a boat with a sprit looks lovely and the thing is really quite good to tie the anchor line to.
With regard to the water damaging the sprit, this shouldn't ever happen. The loads that are put on the sprit by the sails are tens of times larger than the load that could be put on it by the water. The forces on the jib stay could be well in excess of 70,000 pounds on a mid-sized boat, you'd have to be moving the sprit through the water pretty darned fast to come close to that load. So, I'd suggest that you not worry about it.
I would strongly suggest that you think hard about a lighter boat if you think you actually need a sprit, unless you a nostalgic old fart like me who just likes the way they look.
ancient kayaker
10-21-2009, 09:51 PM
A bowsprit gets my vote any day for appearance. I wonder if I can put one on my 3m boat.
capt vimes
10-22-2009, 04:42 AM
Bowsprits have their own stay. There is a forestay attached to the bowstem or close to it
please read perm stress' post....
i understand that this ship attached on the last page has a cutter-rig but the MAIN forestay is mounted to the bow-sprit... this forestay is taking the main load - as i understand - and i do not think that this is a good idea because of incidents like the one perm pointed out...
please read perm stress' post....
i understand that this ship attached on the last page has a cutter-rig but the MAIN forestay is mounted to the bow-sprit... this forestay is taking the main load - as i understand - and i do not think that this is a good idea because of incidents like the one perm pointed out...
MikeJohns
10-23-2009, 12:20 AM
please read perm stress' post....
i understand that this ship attached on the last page has a cutter-rig but the MAIN forestay is mounted to the bow-sprit... this forestay is taking the main load - as i understand - and i do not think that this is a good idea because of incidents like the one perm pointed out...
You can have a varity of combinations of forestays and most bowsprit designs will often have an inner stay or two, and will usually require this for a storm jib.
Appendages like keels rudders and bowsprits do fall off at times but look to the design if you want them to remain attached, you will allaways find incidents of failure for anything,
some older working boats had sprits that were run out with a tackle once at sea With the line with one turn around a post these bowsprits could be used to ram the dock wall at low speed to stop the vessel and they withstood even that treatment :)
i understand that this ship attached on the last page has a cutter-rig but the MAIN forestay is mounted to the bow-sprit... this forestay is taking the main load - as i understand - and i do not think that this is a good idea because of incidents like the one perm pointed out...
You can have a varity of combinations of forestays and most bowsprit designs will often have an inner stay or two, and will usually require this for a storm jib.
Appendages like keels rudders and bowsprits do fall off at times but look to the design if you want them to remain attached, you will allaways find incidents of failure for anything,
some older working boats had sprits that were run out with a tackle once at sea With the line with one turn around a post these bowsprits could be used to ram the dock wall at low speed to stop the vessel and they withstood even that treatment :)
ancient kayaker
10-23-2009, 01:27 AM
... some older working boats had sprits that were run out with a tackle once at sea With the line with one turn around a post these bowsprits could be used to ram the dock wall at low speed to stop the vessel and they withstood even that treatment :)
Would that work when some seadoo is approaching on a collision course at full speed while the driver is chatting over his shoulder with his girlfriend? Would anyone be offended if it were sharpened?
Would that work when some seadoo is approaching on a collision course at full speed while the driver is chatting over his shoulder with his girlfriend? Would anyone be offended if it were sharpened?
capt vimes
10-23-2009, 03:29 AM
some older working boats had sprits that were run out with a tackle once at sea With the line with one turn around a post these bowsprits could be used to ram the dock wall at low speed to stop the vessel and they withstood even that treatment :)
oh - i know that but...
this is the 21st century and bowsprits in modern shipbuilding are imo just there to sail a gennaker, spi, blister etc from them and to keep the anchor away from the hull if you are not able or willing to store it in its compartement...
and therefore i think that a bowsprit should never be part or take anything from the rig.... it has become nothing but an appendage and if it falls off... no harm done - eh? ;)
nobody is using a bowsprit nowadays as a ram... or have it as an integral part of the sailplan and rig... there is no reason for doing so.
but i must confess that my focus is solemnly on sailyachts used for recreational purposes and cruising... racing is something different still and workboats i have no clue about whatsoever.... :p
oh - i know that but...
this is the 21st century and bowsprits in modern shipbuilding are imo just there to sail a gennaker, spi, blister etc from them and to keep the anchor away from the hull if you are not able or willing to store it in its compartement...
and therefore i think that a bowsprit should never be part or take anything from the rig.... it has become nothing but an appendage and if it falls off... no harm done - eh? ;)
nobody is using a bowsprit nowadays as a ram... or have it as an integral part of the sailplan and rig... there is no reason for doing so.
but i must confess that my focus is solemnly on sailyachts used for recreational purposes and cruising... racing is something different still and workboats i have no clue about whatsoever.... :p
Milan
11-01-2009, 01:33 PM
Long ago boats were quite heavy and had tremendous drag
. needed a BIG sail plan
gaff cutter
beautiful to look at, they are a bear to sail ,,,
the boat of modern materials light no need for the massive sail area
All of that said, a boat with a sprit looks lovely and the thing is really quite good to tie the anchor line to.
nostalgic just likes the way they look.
It isn't oftenly done, but combining modern light materials and ancient sail plane can produce very interesting boat.
I think that you could possibly like this high performance gaff cutter:
http://www.balta.fr/etoilehori2.html
the boat of modern materials light no need for the massive sail area
All of that said, a boat with a sprit looks lovely and the thing is really quite good to tie the anchor line to.
nostalgic just likes the way they look.
It isn't oftenly done, but combining modern light materials and ancient sail plane can produce very interesting boat.
I think that you could possibly like this high performance gaff cutter:
http://www.balta.fr/etoilehori2.html
ancient kayaker
11-01-2009, 02:05 PM
It's beautiful! Except for the house on the deck that is - looks like a container vessel. That hull shape doesn't look all that ancient though.
Milan
11-01-2009, 04:57 PM
… house on the deck …
Dog house can be easily omitted, as on this one:
http://www.balta.fr/chiloe.html
However, that could mean quite limited headroom bellow, as she is shallow under water line and has a low freeboard.
… That hull shape doesn't look all that ancient though.
No, hull shape is not ancient at all. That’s why she is a rocket.
She certainly rises quite a few eye-brows, when she sails circles around modern and fast looking boats. I think that many sailors who automatically dismiss gaff rig as slow, would think twice if they see this boat in action.
Etiole Horizon's bowsprit:
Dog house can be easily omitted, as on this one:
http://www.balta.fr/chiloe.html
However, that could mean quite limited headroom bellow, as she is shallow under water line and has a low freeboard.
… That hull shape doesn't look all that ancient though.
No, hull shape is not ancient at all. That’s why she is a rocket.
She certainly rises quite a few eye-brows, when she sails circles around modern and fast looking boats. I think that many sailors who automatically dismiss gaff rig as slow, would think twice if they see this boat in action.
Etiole Horizon's bowsprit:
DGreenwood
11-01-2009, 05:50 PM
It's beautiful! Except for the house on the deck that is - looks like a container vessel. That hull shape doesn't look all that ancient though.
I think you might be confusing Life Line Banners with a deck house. Enlarge the pic and look closer.
Fun boat!
I think you might be confusing Life Line Banners with a deck house. Enlarge the pic and look closer.
Fun boat!
MikeJohns
11-02-2009, 06:15 AM
...........
She certainly rises quite a few eye-brows, when she sails circles around modern and fast looking boats. I think that quite a few sailors who automatically dismiss gaff rig as slow, would think twice if they see this boat in action.
Interesting but if you couldn't fly the topsail to windward the lift-drag ratio would be poor, always the achiles heel of the gaff rig is the short luff on the mainsail for windward work.
If yo know the vessel and the designer I'd be very interested to know if they produced any polars.
cheers
She certainly rises quite a few eye-brows, when she sails circles around modern and fast looking boats. I think that quite a few sailors who automatically dismiss gaff rig as slow, would think twice if they see this boat in action.
Interesting but if you couldn't fly the topsail to windward the lift-drag ratio would be poor, always the achiles heel of the gaff rig is the short luff on the mainsail for windward work.
If yo know the vessel and the designer I'd be very interested to know if they produced any polars.
cheers
Paul B
11-02-2009, 02:40 PM
Thats why she is a rocket.
She certainly rises quite a few eye-brows, when she sails circles around modern and fast looking boats.
Can you give us details of these feats of speed?
When this boat did the Route du Rhum 2002 it was outclassed, terribly slow compared to the rest of the 50 footers. I believe it was sitting in last place, more than 1200 miles behind, when the first boat in class finished. It was more than 600 miles behind the next to last boat, IIRC.
She certainly rises quite a few eye-brows, when she sails circles around modern and fast looking boats.
Can you give us details of these feats of speed?
When this boat did the Route du Rhum 2002 it was outclassed, terribly slow compared to the rest of the 50 footers. I believe it was sitting in last place, more than 1200 miles behind, when the first boat in class finished. It was more than 600 miles behind the next to last boat, IIRC.
Milan
11-03-2009, 01:24 PM
Interesting but if you couldn't fly the topsail to windward the lift-drag ratio would be poor, always the achiles heel of the gaff rig is the short luff on the mainsail for windward work….
Yes, short luff is gaff’s weakness , but this boat is stiff, she can fly top sail most of the time, and it seems that sails have a very good shape, including the top sail. No buggy, sagging sails one usually expects from the gaffer. So, she is able to sail very well to the windward, pointing a little lower then she would with highly roached bermudian sail plan, but still doing very fine.
… If you know the vessel and the designer I'd be very interested to know if they produced any polars.
cheers
I don’t know designer personally and I couldn’t find any polars, unfortunately. Designer claims that her best speeds are about 11 knots to windward and around 15 reaching.
Can you give us details of these feats of speed?
When this boat did the Route du Rhum 2002 it was outclassed, terribly slow compared to the rest of the 50 footers. I believe it was sitting in last place, more than 1200 miles behind, when the first boat in class finished. It was more than 600 miles behind the next to last boat, IIRC.
Actually, in 2002 Adecco Etoile Horizon lost time because she, (solo skipper Bob Escoffier), diverted from the race course to rescue Karine Fauconnier from her heavily damaged trimaran nearby Madeira.
But that isn’t really relevant to this thread. I wasn’t talking about racing. At the time of Route du Rhum she was stripped out racer, with 8.5 tons displacement, Bermudian rig, and considerably deeper fin.
With her wooden strip planked hull and aluminum mast she is not competitive racer against new generation open class boats.
She is transformed in the fast cruiser. With cruising accommodation she is about two tons heavier, has a shallower bulb fin, but still, a very fast boat. Can you imagine surprised faces on the modern looking boats when they see gaff cutter sailing at 15 knots? Looks like a lot of fun.
This is how Adecco Etoile Horizon looked during her racing days:
Yes, short luff is gaff’s weakness , but this boat is stiff, she can fly top sail most of the time, and it seems that sails have a very good shape, including the top sail. No buggy, sagging sails one usually expects from the gaffer. So, she is able to sail very well to the windward, pointing a little lower then she would with highly roached bermudian sail plan, but still doing very fine.
… If you know the vessel and the designer I'd be very interested to know if they produced any polars.
cheers
I don’t know designer personally and I couldn’t find any polars, unfortunately. Designer claims that her best speeds are about 11 knots to windward and around 15 reaching.
Can you give us details of these feats of speed?
When this boat did the Route du Rhum 2002 it was outclassed, terribly slow compared to the rest of the 50 footers. I believe it was sitting in last place, more than 1200 miles behind, when the first boat in class finished. It was more than 600 miles behind the next to last boat, IIRC.
Actually, in 2002 Adecco Etoile Horizon lost time because she, (solo skipper Bob Escoffier), diverted from the race course to rescue Karine Fauconnier from her heavily damaged trimaran nearby Madeira.
But that isn’t really relevant to this thread. I wasn’t talking about racing. At the time of Route du Rhum she was stripped out racer, with 8.5 tons displacement, Bermudian rig, and considerably deeper fin.
With her wooden strip planked hull and aluminum mast she is not competitive racer against new generation open class boats.
She is transformed in the fast cruiser. With cruising accommodation she is about two tons heavier, has a shallower bulb fin, but still, a very fast boat. Can you imagine surprised faces on the modern looking boats when they see gaff cutter sailing at 15 knots? Looks like a lot of fun.
This is how Adecco Etoile Horizon looked during her racing days:
ancient kayaker
11-03-2009, 02:41 PM
I wonder if there is comparative data of her performance under the two different rigs and race vs cruise configuration? It's not often we get the chance to see such a change on the same hull.
Mike's story of ramming the dock to stop the boat reminds me of a story about a great canadian, rear-Admiral Bob Welland. When worked in Ottawa a few decades back he was the company's GM and many stories both true and apocryphal went the rounds. My favorite was of his habit of approaching the dock at full speed in a destroyer during WW2 and ordering full reverse, just stopping in time. His judgement was impeccable.
Then he received command of a cruiser and tried the same thing. Standing stiffly on the bridge, No. 1 expressed the opinion "we're going to hit aren't we" and Capt Welland agreed. Fortunately alert crews onboard and on the dock managed to get lines wrapped around a bollard or two and helped to stop the brand-new ship inches from embarassment.
Mike's story of ramming the dock to stop the boat reminds me of a story about a great canadian, rear-Admiral Bob Welland. When worked in Ottawa a few decades back he was the company's GM and many stories both true and apocryphal went the rounds. My favorite was of his habit of approaching the dock at full speed in a destroyer during WW2 and ordering full reverse, just stopping in time. His judgement was impeccable.
Then he received command of a cruiser and tried the same thing. Standing stiffly on the bridge, No. 1 expressed the opinion "we're going to hit aren't we" and Capt Welland agreed. Fortunately alert crews onboard and on the dock managed to get lines wrapped around a bollard or two and helped to stop the brand-new ship inches from embarassment.
Perm Stress
11-06-2009, 11:44 AM
by BeauVrolyk:
BeauVrolyk "I would hold that there are a number of advantages to bow-sprits, but that modern boats probably don't need them, except down wind."
Agree...
the problem (or just property, or feature -depend on point of view) with modern boats is that most of them are perfectly balanced for upwind or very close reach work, while for any course further off the balance simply disappear...
Here is the place for bowsprit with additional sail!
And, if not the measurement J (base of fore triangle), I believe it would far more widely used.
I will try to post a photo of 45 feet boat I was skippering for time long enough to invent a makeshift bowsprit for her.
BeauVrolyk "I would hold that there are a number of advantages to bow-sprits, but that modern boats probably don't need them, except down wind."
Agree...
the problem (or just property, or feature -depend on point of view) with modern boats is that most of them are perfectly balanced for upwind or very close reach work, while for any course further off the balance simply disappear...
Here is the place for bowsprit with additional sail!
And, if not the measurement J (base of fore triangle), I believe it would far more widely used.
I will try to post a photo of 45 feet boat I was skippering for time long enough to invent a makeshift bowsprit for her.
Perm Stress
11-06-2009, 11:57 AM
There is a picture..
This boat is not quite modern by today's standards, but still not oldtimer either.
She has quite a long keel, separate rudder with narrow full depth skeg.
And is a bermuda schooner as could be seen.
(And, by the way, her high roached foresail was ordered half a year before first pictures of similarly rigged big schooners were published in Yachting World magazine. :cool: )
What was an effect..:
Before: close hauled, sometimes close reaching you could lash the wheel for hours, no matter if there is any wave or not. But not for beam reach or further.
After: you could lash the helm for hours up to broad reaching (~135 TWA).
Also speed: in light winds, at about 130-150 TWA, Force 2-3, hoisting this flying yankee on a bowsprit is a difference between ~3.5 and ~5.2 knots.
Out of all proportion to additional sail area.
This boat is not quite modern by today's standards, but still not oldtimer either.
She has quite a long keel, separate rudder with narrow full depth skeg.
And is a bermuda schooner as could be seen.
(And, by the way, her high roached foresail was ordered half a year before first pictures of similarly rigged big schooners were published in Yachting World magazine. :cool: )
What was an effect..:
Before: close hauled, sometimes close reaching you could lash the wheel for hours, no matter if there is any wave or not. But not for beam reach or further.
After: you could lash the helm for hours up to broad reaching (~135 TWA).
Also speed: in light winds, at about 130-150 TWA, Force 2-3, hoisting this flying yankee on a bowsprit is a difference between ~3.5 and ~5.2 knots.
Out of all proportion to additional sail area.
ancient kayaker
11-06-2009, 06:00 PM
That is an amazing improvement. From your previous post I gather much of this results from better balance. Does the extra efficiency come from sail power or reduced rudder drag?
Perm Stress
11-07-2009, 08:32 AM
"That is an amazing improvement. From your previous post I gather much of this results from better balance. Does the extra efficiency come from sail power or reduced rudder drag?"
I wish I know this...
I think from both, with more pure power adding better part. This is based on just a feeling of uninterrupted, continuous pulling power such setup is developing. Less rudder work also should have something to do with it.
Also I have noticed many times in different boats, that at broader appearent wind angles, multi sail setup is more resistant to stall, -boat much less often experience temporary drops in speed...
I wish I know this...
I think from both, with more pure power adding better part. This is based on just a feeling of uninterrupted, continuous pulling power such setup is developing. Less rudder work also should have something to do with it.
Also I have noticed many times in different boats, that at broader appearent wind angles, multi sail setup is more resistant to stall, -boat much less often experience temporary drops in speed...
CHARMIANOFPOOLE
11-09-2009, 03:33 PM
37166
Hi,
Our boat "Charmian of Poole" is based on a British Pilot Cutter & has a deck length of 38' with a Bowsprit extending 20' from the stem.
In heavy sea's we have to withdraw & secure, reef the Gaff Mainsail & only use our Staysail hanked onto the stem forestay.
Our mast carries a fidded topmast of 22' & we have found that when the Bowsprit dives into the water the running stay attached slackens badly & on the upward motion the Bowsprit bends almost to the point of breaking due to no tension on the running stay. The Stay snaps taught & this in turn bends the Topmast forward straining the running backstays.
A Good example of what this can cause if not checked early is to be found on www.workingsail.co.uk under the heading "Yard News"
The Pilot Cutter "Agnes" was on passage from the Isle of Mann UK through the Irish sea flying her Jib from her Bowsprit & a Topsail. She dived into a trough snapping her Bowsprit & bringing down her Topmast.
Regards
Lez Arkell
Hi,
Our boat "Charmian of Poole" is based on a British Pilot Cutter & has a deck length of 38' with a Bowsprit extending 20' from the stem.
In heavy sea's we have to withdraw & secure, reef the Gaff Mainsail & only use our Staysail hanked onto the stem forestay.
Our mast carries a fidded topmast of 22' & we have found that when the Bowsprit dives into the water the running stay attached slackens badly & on the upward motion the Bowsprit bends almost to the point of breaking due to no tension on the running stay. The Stay snaps taught & this in turn bends the Topmast forward straining the running backstays.
A Good example of what this can cause if not checked early is to be found on www.workingsail.co.uk under the heading "Yard News"
The Pilot Cutter "Agnes" was on passage from the Isle of Mann UK through the Irish sea flying her Jib from her Bowsprit & a Topsail. She dived into a trough snapping her Bowsprit & bringing down her Topmast.
Regards
Lez Arkell
View Full Version : Bow sprit in high seas.
Legal
Boat Design Forums
Gallery
Directory
Boat Design & Boatbuilding Bookstore
Powerboat Ads
Sailboat Ads
powered by vBulletin which is copyright ©2000-2008, Jelsoft Enterprises Ltd.
Web Site Design and Content Copyright ©1999-2008 Boat Design Net
powered by vBulletin which is copyright ©2000-2008, Jelsoft Enterprises Ltd.
Web Site Design and Content Copyright ©1999-2008 Boat Design Net