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Old August 27th 05, 03:13 AM
John Smith
 
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Default Fiberglassing my daggerboard?

I would like to drill a couple holes in my mahogany daggerboard (on a 13'
boat) and fill them with lead.
Although I am sure the boat can handle it, I am not so sure about the
daggerboard. I am thinking of sanding an 1/8" of an inch off it all around
(or maybe routing it, that should be more precise and faster...) and
wrapping it with fiberglass; a couple inches further up than the lead. It
seems to me that a few pounds of lead at the end of the daggerboard ought to
add significant stability to a small boat.
I figure the fiberglass will add more strength than the holes take away.
I am not particularly knowledgeable about these things, so it is entirely
possible I am overlooking something that will make this a stupid project.
(I have lost 8 pounds this year, and plan to lose some more; so I am not
concerned about the effect of a few pounds of lead on the boat.)



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Old August 27th 05, 04:12 AM
Tom Dacon
 
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A few pounds of lead added to to your daggerboard on a 13' boat will not
make any significant difference in stability. Hiking out about a
quarter-inch farther will do more for the boat's stability than any
reasonable amount of lead would do.

The reason people used to add lead to centerboards and daggerboards was just
to counteract the buoyancy of the wood, and to keep them from floating up in
the slot.

If you want to do something more useful, shape the daggerboard into a really
accurate NACA foil cross-section. Do the same with your rudder. If the
cross-section of those two foils is kind of crude now, you'll be amazed at
the difference.

Tom Dacon

"John Smith" wrote in message
news
I would like to drill a couple holes in my mahogany daggerboard (on a 13'
boat) and fill them with lead.
Although I am sure the boat can handle it, I am not so sure about the
daggerboard. I am thinking of sanding an 1/8" of an inch off it all
around
(or maybe routing it, that should be more precise and faster...) and
wrapping it with fiberglass; a couple inches further up than the lead. It
seems to me that a few pounds of lead at the end of the daggerboard ought
to
add significant stability to a small boat.
I figure the fiberglass will add more strength than the holes take away.
I am not particularly knowledgeable about these things, so it is entirely
possible I am overlooking something that will make this a stupid project.
(I have lost 8 pounds this year, and plan to lose some more; so I am not
concerned about the effect of a few pounds of lead on the boat.)




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Old August 27th 05, 02:11 PM
Roger Derby
 
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I'd suggest that the lead will be useful, mainly, for keeping the
daggerboard from floating up. On a small boat, the crew's weight is so much
larger that any moment supplied by the lead will be hard to see (unless you
want the boat to be able to sail away without you like my Sunfish did).

I think you're right about the fiberglass skin being more than adequate for
any lost strength. The material in the middle of a beam is there mainly to
keep the edges apart, and the lead won't compress. You might want to
calculate the areas for various schemes. One slightly larger hole will have
as much area/volume as two smaller holes and it will be easier to key the
edges to hold the lead.

Roger

http://home.earthlink.net/~derbyrm
"John Smith" wrote in message
news
I would like to drill a couple holes in my mahogany daggerboard (on a 13'
boat) and fill them with lead.
Although I am sure the boat can handle it, I am not so sure about the
daggerboard. I am thinking of sanding an 1/8" of an inch off it all
around
(or maybe routing it, that should be more precise and faster...) and
wrapping it with fiberglass; a couple inches further up than the lead. It
seems to me that a few pounds of lead at the end of the daggerboard ought
to
add significant stability to a small boat.
I figure the fiberglass will add more strength than the holes take away.
I am not particularly knowledgeable about these things, so it is entirely
possible I am overlooking something that will make this a stupid project.
(I have lost 8 pounds this year, and plan to lose some more; so I am not
concerned about the effect of a few pounds of lead on the boat.)




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Old August 27th 05, 02:32 PM
John Smith
 
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Default


"Tom Dacon" wrote in message
...
A few pounds of lead added to to your daggerboard on a 13' boat will not
make any significant difference in stability. Hiking out about a
quarter-inch farther will do more for the boat's stability than any
reasonable amount of lead would do.

The reason people used to add lead to centerboards and daggerboards was

just
to counteract the buoyancy of the wood, and to keep them from floating up

in
the slot.

Well, there's that too; it does tend to float up a 2 or 3 inches unless the
side pressure is enough to keep it down.

If you want to do something more useful, shape the daggerboard into a

really
accurate NACA foil cross-section. Do the same with your rudder. If the
cross-section of those two foils is kind of crude now, you'll be amazed at
the difference.

Thats one thing I will say for the boat; both daggerboard and rudder have
great cross-sections. Don't know why it (Starwing) was a failure; the
workmanship is very good..


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Old August 27th 05, 03:08 PM
Roger Derby
 
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Don't know what the numbers are for this case, but the Sunfish is a pretty
good boat, and with well over 500,000 kicking around, it's easy to find a
"class" race or a replacement part. Market timing???

What does the Starwing weigh? Every year some new graduate of our sailing
class would buy a ??? (Sunfish knockoff), sail it for the season, discover
that it weighed twice what the Sunfish did, and sell it. That particular
boat changed hands some six times in the four years I was sailing there. It
only looked like it would be competitive.

My fat belly meant that the 19 year olds would get up on a plane some ten or
twenty feet before I did and stay on for an additional distance when the
wind faltered. Of course they also could also hike out further and stay
there longer.

Roger

http://home.earthlink.net/~derbyrm
"John Smith" wrote in message
...

Don't know why it (Starwing) was a failure; the
workmanship is very good..





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Old August 27th 05, 03:35 PM
Toller
 
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Default


What does the Starwing weigh?


Starwing is a completely different animal. It has a lot of sail (the number
escapes me at the moment) for a boat it's size, with a main and jib. It is
very narrow at the water line, but then swells out broadly above (I figure
that is the "wing"). The wood is all mahagony, and everything is done very
nicely. The fiberglass is very thin, and the boat is light.

At least it was until I "fixed" it. I got it really cheap because it had
cracks in both sides from rough trailering. Since I don't plan on
trailering it ever, I put some fiberglass over the cracks and it is fine
now; if a bit heavier.
Frankly though, I am not much of a sailor, and I couldn't handle it in winds
over 5mph; it was just too responsive and would capsize in a gust before I
knew what happened. It is much better now with a few pounds of new
fiberglass.

However, last week I took it out in 10-15 winds, but headed home when the
winds picked up. Before I could get home a huge gust too it over, despite
my hiking out as far as I could go. I am hoping some weight in the
daggerboard will add a small cushion.


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Old August 27th 05, 05:35 PM
Sam
 
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John Smith wrote:
"Tom Dacon" wrote in message
The reason people used to add lead to centerboards and daggerboards was

just
to counteract the buoyancy of the wood, and to keep them from floating up

in
the slot.

Well, there's that too; it does tend to float up a 2 or 3 inches unless the
side pressure is enough to keep it down.


I had a Sailfish that had a short piece of rope that you would secure
over the top of the daggerboard to keep it from floating up. I also
don't think what you propose with thw lead would show any results
comparable to the effort.Sam

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Old August 27th 05, 05:45 PM
Toller
 
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On rec.woodworking, I asked about how to drill the holes parallel to the
sides. Someone suggested going in with a hole saw through the sides. That
will weaken the board, but done down low where there is no torque, that
should not matter; expecially if I go over it with fiberglass. And I could
get in more lead.
I suppose my concern there would be after a capsize, when I pulling down on
the board to get the boat back up I would be putting a lot of force on a
weakened area. Hmm..

I know I can't get in enough weight to make it self-righting or anything
like that, but just giving me a little more time to react to gusts would be
nice.


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Old August 27th 05, 06:40 PM
William R. Watt
 
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Default


A piece of shock cord from the top of the daggerboard forward and down to
some point on the boat will keep it from floating up in the slot.

Letting out the mainsheet to dump wind will do more for stability than
adding lead to the daggerboard.

Can you reef the sail? Can you add reef points to the sail? Can you wrap
some sail around the mast? Reducing the size of the sail will reduce its
power.

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Old August 27th 05, 08:05 PM
Roger Derby
 
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One should never (hardly ever?) capsize on a beat or a reach. Running
downwind is a different question.

DO NOT CLEAT THE MAIN SHEET FAST. Letting it run in a gust depowers the
sail.

DO NOT TAKE YOUR HAND OFF THE TILLER. Heading up in a gust depowers the
sail. (And gains distance to windward when beating.)

Reducing sail makes life easier, but if you have the sheet free and are
ready to head up with a quick twitch of the tiller, you can unload
instantly. Hiking out is good for boat speed, but not required to avoid a
capsize.

My Sunfish came from the factory with a simple hook on the front center of
the cockpit. Someone had replaced this with a cam cleat, but that's too
risky. I put back the hook. Since I'm lazy, I added clam cleats on each of
the side decks. On a beat or reach these are right under my hand and I can
free the sheet in an instant. Note that's cam = bad and clam = good.

Running down wind is risky. If you have too much sail up you should
consider tacking down wind.

Remember, with the Sunfish we're talking 90+ square feet of sail on a 150 lb
boat that has no reef points and no ballast. Not as "responsive" as a wind
surfer, but it can get exciting. Running before a squall line once I
actually had a rooster tail from the rudder. I didn't capsize but when I
tried to round up and come about to fetch the finish line I slid off into
the water and it sailed away without me. (Didn't matter since the committee
boat broke its anchor rode, the safety boat pitch poled, and those that
didn't capsize ran way up on the shore.)

Roger

http://home.earthlink.net/~derbyrm

"Toller" wrote in message
...
snip
Frankly though, I am not much of a sailor, and I couldn't handle it in
winds
over 5mph; it was just too responsive and would capsize in a gust before I
knew what happened. It is much better now with a few pounds of new
fiberglass.

However, last week I took it out in 10-15 winds, but headed home when the
winds picked up. Before I could get home a huge gust too it over, despite
my hiking out as far as I could go. I am hoping some weight in the
daggerboard will add a small cushion.






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