DSK wrote (in another thread):
Actually, I think it would be a good project to add positive
flotation to any cruising boat that ventures out into big water.
Some care should be taken with the volume distribution , so that
stability is mainatained, as well as ensuring sufficient volume.
You could utilize the interior angles & odd nooks so as to not
lose too much stowage.

How do I figure out how many cubic feet of foam I need to add
to a 46' Tayana Pilot without filling it with water ?

Hull: Fiberglass
Displacement: 34,500 lbs
Ballast: 11,000 lbs

For more details see http://www.tayanayachts.com.tw/V460.htm
and http://tayana46.tripod.com

It has a watertight bulkhead in the bow and a large storeroom
(lazarette) in the stern. Do you think it would be enough to just
put the floatation blocks in these areas ?

For salt water:

34,500 / (64 - weight of foam per cubic foot) = cubic feet of foam
required if you want your wreck to be just neutrally buoyant. Since
that won't be much use for survival and would sink if you are carrying
even an extra wrench, you should add 10 - 20% to insure that something
remains above water to cling to and provide visibility to searchers.

After you do these calculations, you'll see why more boats don't have
foam in them.

--

Roger Long



wrote in message
nk.net...

DSK wrote (in another thread):
Actually, I think it would be a good project to add positive
flotation to any cruising boat that ventures out into big water.
Some care should be taken with the volume distribution , so that
stability is mainatained, as well as ensuring sufficient volume.
You could utilize the interior angles & odd nooks so as to not
lose too much stowage.

How do I figure out how many cubic feet of foam I need to add
to a 46' Tayana Pilot without filling it with water ?

Hull: Fiberglass
Displacement: 34,500 lbs
Ballast: 11,000 lbs

For more details see http://www.tayanayachts.com.tw/V460.htm
and http://tayana46.tripod.com

It has a watertight bulkhead in the bow and a large storeroom
(lazarette) in the stern. Do you think it would be enough to just
put the floatation blocks in these areas ?

On Wed, 16 Nov 2005 09:03:09 GMT, wrote:


DSK wrote (in another thread):
Actually, I think it would be a good project to add positive
flotation to any cruising boat that ventures out into big water.
Some care should be taken with the volume distribution , so that
stability is mainatained, as well as ensuring sufficient volume.
You could utilize the interior angles & odd nooks so as to not
lose too much stowage.

How do I figure out how many cubic feet of foam I need to add
to a 46' Tayana Pilot without filling it with water ?

Hull: Fiberglass
Displacement: 34,500 lbs
Ballast: 11,000 lbs

For more details see http://www.tayanayachts.com.tw/V460.htm
and http://tayana46.tripod.com

It has a watertight bulkhead in the bow and a large storeroom
(lazarette) in the stern. Do you think it would be enough to just
put the floatation blocks in these areas ?


Freezing water is 62.4 lb/cu ft. Say the foam weighs nothing.
You need displacement divided by water weight per cu ft =
34500/62.4 = 553 cu ft. Add 10% for luck = 600 cu ft.

That's two chunks measuring 6 X 7 X 7 ft. each.

Brian Whatcott Altus OK

Brian Whatcott wrote:
On Wed, 16 Nov 2005 09:03:09 GMT, wrote:
How do I figure out how many cubic feet of foam I need to add
to a 46' Tayana Pilot without filling it with water ?

Hull: Fiberglass
Displacement: 34,500 lbs
Ballast: 11,000 lbs

For more details see http://www.tayanayachts.com.tw/V460.htm
and http://tayana46.tripod.com

It has a watertight bulkhead in the bow and a large storeroom
(lazarette) in the stern. Do you think it would be enough to just
put the floatation blocks in these areas ?


Freezing water is 62.4 lb/cu ft. Say the foam weighs nothing.
You need displacement divided by water weight per cu ft =
34500/62.4 = 553 cu ft. Add 10% for luck = 600 cu ft.

That's two chunks measuring 6 X 7 X 7 ft. each.

If it was designed into the boat, it would be 13 cu ft per foot, or
about 3 inches thick around the hull and deck. This would also add a
lot of stiffness, insulation, collision protection, etc. However, if
you were doing it from scratch, you'd probably pick a much lighter
design - the Etap 46 is 27000 lbs while the Tayana is actually 42000.

Jeff wrote:
...
If it was designed into the boat, it would be 13 cu ft per foot,
or about 3 inches thick around the hull and deck. This would
also add a lot of stiffness, insulation, collision protection, etc.
However, if you were doing it from scratch, you'd probably
pick a much lighter design - the Etap 46 is 27000 lbs while
the Tayana is actually 42000.

Maybe it's easier to make a MacGregor seaworthy than to make
a Tayana unsinkable :-)

"Unsinkable" works for Boston Whaler, but didn't work out too well for the
Titanic.
What about sealing the boats storage lockers? You could have some sort of
plugs for the limber holes to be kept handy and only used if things got
scary.
MMC
wrote in message
nk.net...

Jeff wrote:
...
If it was designed into the boat, it would be 13 cu ft per foot,
or about 3 inches thick around the hull and deck. This would
also add a lot of stiffness, insulation, collision protection, etc.
However, if you were doing it from scratch, you'd probably
pick a much lighter design - the Etap 46 is 27000 lbs while
the Tayana is actually 42000.

Maybe it's easier to make a MacGregor seaworthy than to make
a Tayana unsinkable :-)

Jeff wrote:
If it was designed into the boat, it would be 13 cu ft per foot,
or about 3 inches thick around the hull and deck. This would
also add a lot of stiffness, insulation, collision protection, etc.
However, if you were doing it from scratch, you'd probably
pick a much lighter design - the Etap 46 is 27000 lbs while
the Tayana is actually 42000.


Tells you something about the supposed practicality of extremely heavy
boats, doesn't it?

Anyway you should subtract the tankage from the displacement figure,
because it's already flotation. And it is easy to picture the volume
required, if you fill the hull up to 1" above the LWL with bouyancy, you
have created an unsinkable boat... what's more, one in which the volume
distribution of the flotation is guaranteed to keep it stable.

wrote:
Maybe it's easier to make a MacGregor seaworthy than to make
a Tayana unsinkable :-)

That's easy, just redefine "seaworthy" and print up a few advertising
brochures.

Fresh Breezes- Doug King

wrote:
DSK wrote (in another thread):
Actually, I think it would be a good project to add positive
flotation to any cruising boat that ventures out into big water.
Some care should be taken with the volume distribution , so that
stability is mainatained, as well as ensuring sufficient volume.
You could utilize the interior angles & odd nooks so as to not
lose too much stowage.

How do I figure out how many cubic feet of foam I need to add
to a 46' Tayana Pilot without filling it with water ?

Hull: Fiberglass
Displacement: 34,500 lbs
Ballast: 11,000 lbs

For more details see http://www.tayanayachts.com.tw/V460.htm
and http://tayana46.tripod.com

It has a watertight bulkhead in the bow and a large storeroom
(lazarette) in the stern. Do you think it would be enough to just
put the floatation blocks in these areas ?

Their is a company that makes side rails that are inflatable. Not so
sure how good they are, lots of people die in accidents on boats with
flotation, most roll over when filled with water and acted upon by
waves. If your that concerned maintain the boat properly, you can set
the engine(s) up with crash valves, carry good insurance and invest in
a raft. Things happen when your on the water, being prepared is the
most important thing to be.