Help!
I have run across an absolutley lovely 1954 Sparkman and Stephens 39ft
yawl.Double hull. Its one major problem is rot amidships from the shear to 5
planks down. The owner has tried to minimize the damage, but has deferred this
too long. I am afraid about what could be cooking between the hulls right now.
the hull is mahogany but I am thinking that marine plywood ripped to planks
would be better. ANyway figuring on replacing the whole midship section, does
any think I may be able to do this for around $10k US or less?

Hi

"Monarch Canvas" skrev i en meddelelse
...
Help!
I have run across an absolutley lovely 1954 Sparkman and Stephens 39ft
yawl.Double hull. Its one major problem is rot amidships from the shear to
5
planks down. The owner has tried to minimize the damage, but has deferred
this
too long. I am afraid about what could be cooking between the hulls right
now.
the hull is mahogany but I am thinking that marine plywood ripped to
planks
would be better. ANyway figuring on replacing the whole midship section,
does
any think I may be able to do this for around $10k US or less?

Just a detail -------- case you replace with max length plywood this could
be quite short "planks". Then if you make the repair like this, stay with
the boat a few years, how will you be sure such repair will make it easy to
sell the day you want to do that.

P.C.

I think your talking about 'double planked' not double hull..

To make any repairs worth while the cost and effort, you should stay with
the traditional or prescribed method of replacing the planks. Ply wood
planking has none of the strength and longevity that are needed in any boat
planking.. Leave the plywood for plywood boats where the minimum edge grain
is exposed (and then it should be glassed).

First of all the grain of the planking should run parallel with the plank
edges, so a 7ply plywood plank would have only 5 plys parallel and 3 plys
cross grain. Hence you have reduced the strength to ~ 4/7th what it should
be..

Also, all of those end grains in the seam would tend to wick moisture into
the plys. Even a double planked hull will have movement in the seems and
eventually the seam filler will let some moisture in.


--
My opinion and experience. FWIW

Steve
s/v Good Intentions

"Steve" wrote in message
...

First of all the grain of the planking should run parallel with the plank
edges, so a 7ply plywood plank would have only 5 plys parallel and 3 plys
cross grain. Hence you have reduced the strength to ~ 4/7th what it should
be..


Opps! Should read: ".. 4 plys parallel and 3 plys cross grain.... "

Sorry..

Steve
s/v Good Intentions

Get a thorough survey by a surveyor who is competent with older wooden yachts.
Most aren't. These boats are not simple and diagnosing them isn't, either. The
surveyor's report will give you the full list of deficiencies, recommend
materials and methods of repair, and estimate the costs. I'd be surprised if the
prescription includes marine plywood.

S&S was arguably the best US yacht designer of the period. Their boats were built
to the very highest standards and anything less than top grade repair work will
destroy the value of the boat. If you can't afford to do it right, leave the boat
to someone who can.

Jim

Monarch Canvas wrote:

Help!
I have run across an absolutley lovely 1954 Sparkman and Stephens 39ft
yawl.Double hull. Its one major problem is rot amidships from the shear to 5
planks down. The owner has tried to minimize the damage, but has deferred this
too long. I am afraid about what could be cooking between the hulls right now.
the hull is mahogany but I am thinking that marine plywood ripped to planks
would be better. ANyway figuring on replacing the whole midship section, does
any think I may be able to do this for around $10k US or less?

I agree. But it sounds like the OP is trying to pinch the penny on this
boat..

A competent survey is going to cost between $500 and $1000 (because of the
detailed recommendation needed. Around here a routine fiberglass (quickie)
will cost $10/ft and I wouldn't purchase a boat on one of these type..

I'm not saying, not to get a survey, I'm just saying only a serious buyer
with serious intentions for this boat is going to invest that much money
before he even purchases the boat..

This may be a case of a boat for FREE to anyone who wants to assume the
repair expense and responsibility.. It would be in this type of a situation
where a NEWBIE might want to pay for a survey before making the commitment.

Steve
s/v Good Intentions

I don' think 5+3=7??

Monarch Canvas wrote:

Help!
I have run across an absolutley lovely 1954 Sparkman and Stephens 39ft
yawl.Double hull. Its one major problem is rot amidships from the shear to 5
planks down.

heh... boats never have just one problem!

The owner has tried to minimize the damage, but has deferred this
too long. I am afraid about what could be cooking between the hulls right now.
the hull is mahogany but I am thinking that marine plywood ripped to planks
would be better.

I don't think so. If this is a double planked hull, which it sounds like, then the
double layer of planking, alnog with the bond between layers, is a major part of
the structural integrity.



ANyway figuring on replacing the whole midship section, does
any think I may be able to do this for around $10k US or less?

Very doubtful.


Jim Conlin wrote:

Get a thorough survey by a surveyor who is competent with older wooden yachts.
Most aren't. These boats are not simple and diagnosing them isn't, either.

Agreed!


S&S was arguably the best US yacht designer of the period. Their boats were
built
to the very highest standards and anything less than top grade repair work will

destroy the value of the boat.

Agree again, but the issue here is that the value of the boat may already be in
the negative numbers. It's a shame thre aren't more good homes for needy boats...

Fresh Breezes- Doug King

In A-1 condition, this boat could be worth well over $100K. If it's a basket
case, it'll cost even more to get there. Only a competent survey will tell you
whether you're upside-down from the start.

This will not be an inexpensive boat to own.

Steve wrote:

I agree. But it sounds like the OP is trying to pinch the penny on this
boat..

A competent survey is going to cost between $500 and $1000 (because of the
detailed recommendation needed. Around here a routine fiberglass (quickie)
will cost $10/ft and I wouldn't purchase a boat on one of these type..

I'm not saying, not to get a survey, I'm just saying only a serious buyer
with serious intentions for this boat is going to invest that much money
before he even purchases the boat..

This may be a case of a boat for FREE to anyone who wants to assume the
repair expense and responsibility.. It would be in this type of a situation
where a NEWBIE might want to pay for a survey before making the commitment.

Steve
s/v Good Intentions

I'm not saying, not to get a survey, I'm just saying only a serious buyer
with serious intentions for this boat is going to invest that much money
before he even purchases the boat..


Thank you very much for your input. I know a survey will be needed. As far as
the plywood planking, I had seen some nice smaller craft built this way and
thought it might provide an economic solution that would be sound. Apparently
not by theopinions I've gotten. I know absolutely nothing of the science or
engineering of naval design nor the concepts of loads and stresses of
materials, but I have owned and kept afloat wooden boats for 30 years. Ive just
never restored one. Thanks for your input.
Rags