Lofting- Applying the lessons of past Septembers.

Properly lofting the hull of any boat requires a level boat and a reference line- usually the centerline of the boat expressed a short distance from the keel. The reference line is a challenge in an upright boat because the keel blocking often obstructs the ability to express a true centerline.  I learned first hand from my classmates at IYRS last September that the alternative isn't so great. I sidesteped this challenge by making sure the blocking wouldn't interfere with a true center line.

The blocking allows me to tunnel a center line reference under the keel.

Leveling the boat requires a reference line- usually the water line. Two Septembers ago and then again in January I discovered that if the waterline is incomplete or doesn't represent the builder's original line you can have a boat that doesn't sit quite right. So in the case of a restoration it's useful to have that reference line correspond to those found on the construction drawings. For Marlin this presents two problems.

First was that the fire and previous restoration had obliterated a continuous set of scribed waterline marks. The garboards had previously been replaced and the transom refinished so start and end point were impossible determine with any certainty.

Compounding this problem is that the Herreshoff's drawings rely on a construction baseline that has no relation to the actual waterline (it's canted by 5-10 degrees).  This quirk is shared amongst the 12 1/2 family (12 1/2, Alerion, Fish, Marlin, 20 1/2 and Buzzards Bay c.f. Wooden Boat 218) and can lead to confusion when you have construction drawings (Herreshoff's and Mystic Seaport's) that key off of either line- as it did for my team's work on a 12 1/2 replica last year. 

The incomplete waterline data and a desire to level the boat to the construction drawings led me to seek some other visual clue that could establish a proper fore-and-aft level.  Examination of the floors at stations 11 and 14 revealed them to be the same height above baseline. This was true for the original drawing (presumably lifted directly from the Fish Class drawing, Hull #788) and two revised and expanded drawings that date from Marlin's construction.

The Construction Drawing. The water lines are the solid and dashed lines canted at about 5 degrees.  This drawing is not properly dated ("4/1937" penciled with with intials that suggest Bezonton as draftsman) and notes that the 788 Fish class molds are to be used (there was no offset book for the Fish, just a set of notations by NGH on the back of a 12 1/2 model). Addtionally the drawing doesn't indicate whether ASDH or NGH initiated the changes.

Engine and interior space drawing. Note the different construction details for the cabin sole- that's is what first clued me in. This drawing is dated 9/2/38. The date is interesting: it postdates the building of hulls 1420-22 (Marlin is believed to be 1421) furthermore it indicates that the Marlin class was a 'front burner' project when the Great Hurricane struck a week later.  The draftsman was Bezonton and, based on date, it doesn't reflect any input from the recently deceased NGH.

An inspection of floors 11 and 14 suggest they are not replacements from the aborted restoration and their heights correspond to the 1937 construction drawing specs. So I'm pretty confident that I can use them to establish fore and aft level.  I'll only know for certain when I get a chance to loft the long lines.

The faint scorch marks suggest original fabric

For the port and starboard level I've decided to use a camber mold set at station 13 as there aren't scribed waterlines on both sides of the boat amidships. The sheerstrakes are orginal and a subseqent check of scribed waterlines elsewhere on the boat had discrepancies of less than 1/16 of a inch, a fact that raises the confidence of my decision.

Now it was time to start taking lines and getting down to the brass tacks of actual lofting.

August 2011: Work Begins In Earnest

July started off poorly and ended well.  August would invert this as preliminary work started only to be interrupted by Hurricane Irene and the start of school.

Marlin, as you've been able to tell, is just a hull- an abandoned resortation and a few artifacts that survived the fire:

 



Some portside and aft items that survived including the coming,
tiller and sole pieces. The lone surviving spar is the jib club.

 



The starboard side of the rudder was charred...







...but the blank from the previous restoration attempt was preserved.



The very first order of business was to get some the boat secure and level.  The previous restoration attempt had sought to stabilze the sheer with plywood decking (called out by the construction drawings).  Years of outdoor storage and severe damage to the aft deck beams had completely undermined the plywood's rigidity and about half the beams were broken or missing. So we removed the plywood and installed a proper set of crosspalls.

With JC's help we set up staging and got to work removing the dead plywood:

(Before anyone gets in a lather this is the only time JC has worked on the staging without a helmet.)

With all the indignities that Marlin has endured perhaps the most detrimental has been storage on concrete floors without climate control (along with improper keel support).  Most of the planking was dry with seams that had opened up- in some cases to just shy of 1/8th of an inch as shown here...

That's John Goff, Herreshoff Museum COO at the time I surveyed Marlin.

Note the daylight visible particularly on the port side.

More daylight on the port side- also a shot of that nasty plywood and yes....
 that is a crosspall on the right- theirs, not mine

.

It was readily apparent that I would have to assess the condition of the planks to see how they would take to water.  However wetting out dry planking can be tricky business, especially for a boat that's been on the hard for thirty years. Fresh water can promote or accelerate decay and rot, rapid expansion can strain frames or disort planking and there's also the consideration of wastewater.

To avoid these problems I elected to line the interior with burlap sacks impregnated with sea water and then maintain moisture with slop drip soaker hoses.

Planking rehydration kit

So that's how Marlin looked for most of August as JC and I removed beams and made preparations for lofting.  Marlin spent three weeks slowly sipping water. At that point I re-surveyed the planking and, to my surprise, most of the open seams closed up nicely.

Note the faint trace of water along the edges.

While the water ran it's course, I constructed platforms for the lofting and worked on creating a set of reference lines for the boat (more on that in the next post).  Leveling the platforms was particularly difficult since the floor slopes in two directions on either side of a central drainage grate. For that portion of the work I had help from my wife, Shelley:

Shelley helps to establish level for the platforms with a transit stick.

When I pick up from here in my next post I'll discuss the problem of lofting an upright hull- one that's compounded by being a Herreshoff.