Keel and Rudder: Design vs. As-built

Jim Backus designed the 37' LNVT with 3000lbs of ballast to be located just below the waterline and as far outboard as possible.

However, the tug was built with the ballast in the keel.  Did the ballast's relocation result in changes to the keel?  To find out let's compare the tug described in the blueprints to the tug we own, i.e. the as-built tug.

The LNVT's 'Revised Hull Line Drawing', dated 19 June 1981, calls for a 4-3/4" wide keel. This thickness is to be consistent from top to bottom and from stem to stern.

Here's a shot of Thistle 37VT47's keel. Looking at the root (where the keel attaches to the hull) the light makes clear the keel's fore-aft and top-to-bottom tappers. At the aft end of the keel the root is 6" wide while at the bottom it's 5" wide.   Moving along the root towards the bow, the keel's width increases to ~8".  But the bottom of the keel remains 5" wide.

The bottom line: the as-built root is thicker than designed but tapers quickly to almost the specified thickness--5" vs. 4-3/4". There's also some taper along the keel's longitudinal direction which wasn't specified in the plans.

In the above picture the as-built measurements (in red) were made by Allan Seymour, Sally W. 37VT42, the numbers in black are takeoffs from the blue print.  The height of the keel was measured from points 3', 6' and 9' forward from the end of the shoe.  The fillet between the hull and keel makes it difficult to get an exact measurement. While there are differences between the designed and as-built keel, they appear to be minor.   Since there are known differences between the designed and as-built shoe, perhaps basing all measurements from the rudder post's center-line would make more sense.

Most glaring, in these preliminary measurements, is the difference between the designed and as-built rudder. The blueprint calls for an approximate 32"w x 32"h rudder; the as-built is 30"w x 30"h.  The rudderpost's center line was designed to be 6-5/8" aft of the rudder's leading edge; it is actually 3-3/4" aft.

Dave Howell, Nellie D. 37VT63

Yard Productivity and Market Competitivness

According to Daniel Spurr's Heart of Glass, U.S. based Endeavour Yachts more than tripled their productivity between 1984 and 1988.  In 1984 they built 200 sailboats with 308 employees (2/3 boat per employee). In 1988 they built 100 boats with 50 employees (2 boats per employee).  

Contrast this to OEY's peak year, 1986, when 33 boats were built with 250 employees (that's about 1/8 boat per employee).  

If the above is representative of the world boat building industry, several generalizations can be made:

To be competitive a mid 1980's Taiwanese boatyard worker made about 1/5 of their U.S. based counterpart. 

By the late 1980's, and without major productivity increases, OEY could remain in business by paying their employees 1/15 of the U.S. yard worker or by tripling the price of their boats.  Clearly, neither solution by itself is feasible. 

Dave Howell, Nellie D. 37VT63

2015 NE Rendezvous

The NE Rendezvous is now scheduled and we hope you'll be joining us.  It will be in Camden Maine 24-26 July.  You can find all the details at: http://tugin-east-2015.wikidot.com/schedule-of-events. Hope we will be seeing you there!  If you have any questions about the event, please contact the organizer, Sally Seymour at sallyvt@me.com.

LNVT History: "No one really needs a boat."

Lord Nelson Ltd. and Ocean Eagle Yachts went out of business in 1989.  U.S. based Pearson Yachts, the largest recreational boat maker up to that time--at their peak they had nine production lines and sold one new boat per day--went bankrupt in 1991.  Their deeper pockets allowed them to hold on a little longer than Lord Nelson but they too were done in by the same tidal wave of events.  According to Daniel Spurr's Heart of Glass those events included the institution of the 10% luxury tax on new boats, anxiety over the Persian Gulf War, high oil prices, fear of recession, and the flood of good used boats on the market.  William Shaw, Pearson's CEO, reflecting on why his company, along with much of the boat building industry had recently gone under, succinctly said, "No one really needs a boat."  

  Pearson is where Jim Backus got his start designing boats. In fact, in 1982 he'd just left Pearson to hang up his own shingle when he won the 37 Victory Tug commission.  

Dave Howell, Nellie D. 37VT63

  

Thistle 37LN47's Bigger Rudder

Thistle's rudder has had been extended by about 4 inches.  The weld is a very good one but you can see the seam when you look closely.  As a comparison the picture above shows a standard LNVT rudder (the darker image) overlaid on Thistle's rudder.  Thistle tracks through the water like she is on a rail. 

Ed McChain, Thistle 37LN47

Annie's Makeover

Submitted by Craig Kurath, Annie #38

 

We applied a second coat of high build primer on the sheer stripe, sanded that out and applied gray sanding primer.  We are currently sanding out the gray sanding primer. 

 

Victory 37VT02 gets a new mast (Tuggers Vol. 63)

Submitted by Bob Allnutt, Victory 37VT02

It is wonderful to be getting warmer weather; yesterday I painted the aluminum mast that I made for Victory. I applied Interlux Primekote and will apply Interlux Perfection for a top coat. My compressor is not big enough to paint with so I am using a HVLP spraying system that does a fair job. The first coat has some orange peal; I may not have thinned it enough. As the weather permits, I'll apply an additional prime coat and top with Perfection.  

Sally W's Cutwater

Sally W. 37VT42's cutwater is made of stainless steel. It was formed to closely match the stem's curvature. It extends from just beneath the rubrail to well below the water line. Stainless fasteners hold the cutwater to the stem's leading edge.

Replacing the Galley's Countertop (Tugger Vol. 63)

Cutting new laminate to fit perfectly on the galley countertop is tough. John Mackie, John William 37VT68, found a good way to do it. First he removed the fiddle and old laminate. Both came off easily. Then, as the picture shows, he temporarily nailed 1/2" wide wood strips as router guides around the refrigerator's openings. With a piece of laminate laying over the guides and clamped in place, a router mounted trim bit perfectly cut out the countertop's two openings. The wood guides were then removed and the router, using the side of the cabinet as a guide, cut almost all of the rest of the laminate to its finished dimensions. The radius nearest the liquor cabinet, where the router couldn't fit, John used the old laminate as a template.

Fram's Cutwater

The very nice cutwater on Fram 37VT71. It is made of highly polished stainless steel. The stainless conforms to the front of the stem and even flares out with the hull. It is held in place by flush mounted, polished, stainless screws. There appears to be a bedding compound between it and the fiberglass.

A Stainless Cutwater (Stem Guard) Design

Here's the problem, the missing paint clearly shows where the anchor rode and bridle have worried on the stem. The good news is that the missing paint shows exactly how long the new stainless guard needs to be.

Nellie's new $380 stainless stem cover was made from three pieces and welded together. The curvature was gotten by first making a pattern for the port and starboard side pieces.  The front piece was then screwed to the stem and the side pieces tack welded to it.   Part of the finish work included filling in the the temporary holes in the front piece and drilling permanent mounting holes in each side piece.  We elected to go with less than a highly polished finish the thinking being that scratches in the stem were inevitable.  

The bottom edge of the stainless guard was glassed in with 1708 leaving no exposed edges on which the anchor or chain could catch. 

The new boot stripe and stainless stem guard. 

We've used the stem guard for six years and it is working well.  If I had it to do over again there are some changes I'd make.  The fiberglass stem is curved but Nellie's stem guard was made with right angles.  A stem guard that conformed to the curves of the fiberglass underneath it would be a step up in both fit and finish.  The void between Nellie's stainless stem and the fiberglass fills with water.  We added a drain hole in the bottom of the stem.  A better solution would have been to fill the space with a bedding compound.  A screwless mounting system may result in a better look too.  Perhaps the ideal stem guard would be curved to perfectly fit the fiberglass beneath it and be attached with a bedding/mounting material that would both seal out water and hold the guard in place.

Ken Smith, Polar Mist 49VT07, on Haloes (Tuggers Vol 63)

I have had blowout [aka haloes] occur around various thru-hulls from time to time. I repainted my bottom in May of 2013 and my diver has reported some blowout around the stabilizer cutter bars. This is bit premature, usually happens before the three year mark.

I have had multiple discussions with divers and ship-yard managers and have determined the following.

In a bonded system, especially in a hot marina environment, there can be a galvanic reaction between the grounded system and the bottom paint. It requires a very high copper content paint.  I use Pettit Trident SR [same as Sally W. 37VT42 -ed.] which is very high copper. Over the years the exact formula changes and I believe the low VOC brings more loose copper to the surface allowing for greater reaction surface and looser bonds. In essence the copper in the paint is sacrificed. This brings up the old debate about not bonding all underwater parts but placing sacrificial zincs outside. On wood hulls due to wood corrosion, systems are generally not bonded.

This time I have reaction between the stainless cutters and the paint. The cutters are not bonded and the dissimilar metals of stainless and copper seem to be reacting. This has never occurred in the last 15 years but I suspect a change in paint formula and stray currents from a possibly hot boat have contributed to the blowout. I have attached two photos, one of thru-hulls and the other the cutters. 

Due to this problem I am considering switching from a high copper hard paint to a lower copper sacrificial paint.

Ken Smith, kenes@earthlink.net
Polar Mist, 49VT07

Just in from Mike Dunn, Wally 49VT02 (Tuggers Vol. 63)

Need to replace a sea cock?

Consider the Seabung's Breach Control Plug.  Its design allows the maintenance and changing of seacocks afloat.  It is a flexible, elastomeric Polyurethane outer with a stiff, tough ABS core.

More details can be found at:

http://us6.campaign-archive2.com/?u=d2655484a4&id=fb330b19fe&e=cc62b1dbdf

A 35lb CQR in the Anchor Hawse Pipe

"We're dragging", seemed a constant refrain once we started cruising Nellie on the East Coast.  Our Babeth (think Forfjord), which worked flawlessly in the Pacific Northwest, proved less than optimal on the Maryland to Florida ICW, in the Keys, and in the Bahamas.   Danforth anchors are popular here but they are notorious for not resetting and that's problematic as some anchorages have significant tidal currents.  Available anchor choices quickly whittle down to some sort of plow.   Enter the CQR.  

Both Thistle 37VT47 and Kedge 37VT43 have mounted 35lb CQRs on their tugs.   Al Peterson designed an innovative bow mounting while Ed McChain uses the LNVT's existing anchor hawse pipe. It's the hawse pipe mount that we've been using with good success while cruising from Key West to Palm Beach.  The 35lb CQR actually fits quite well in the hawse. 

While retrieving the anchor its shank comes aboard easily.  The top of the shank reaches deck level just as the bottom of the shank enters the hawse.  The flukes rest nicely against the tug's stainless strike plate.   The mounting isn't perfect though.  When the anchor first clears the water its bill can scratch the hull's paint.  In fact, the bill extends beyond the tug's stainless strike plate until the anchor is almost fully up.  Controlling the bill with a boat hook helps mitigate the problem.  Another issue is that even when the anchor is fully up its flukes are free to swivel. In large seas the flukes could pound against the hull.   Thistle's solution, and the one we adopted, is to capture the flukes with a loop of rope, haul up tightly, and then lash the rope's bitter end to the bow's starboard side hawse cleat.  The final issue I want to bring up has to do with aesthetics, and there's no nice way to put this, a 35lb CQR on an LNVT is butt ugly!   They say "Form follows function."  I translate this to mean that I'd rather sleep well than look good.

Written aboard Nellie D. while anchored off Palm Beach using a 7 to 1 scope, 3/8" BBB chain, and a well set 35lb CQR.  The good news is that with her anchor down Nellie is as pretty as her sisters!

Update (20 March 2015) - While beating through some 4' waves the restraint, pictured above, was inadequate as the anchor was hitting the hull.  A second line around the forward fluke was needed.

Faucet Washer Source

The Tiawan faucet washers are available from:

RAINIER PRECISION
PO BOX 77610
SEATTLE, WA. 98177-0610
phone 206-624-8258

Just talked to Jeff from that company and they are sold in 2 packs for $4.95 a pack plus shipping.
If you order the washers, be advised they no longer have the stainless disc inside. Don't know why and didn't get a good reason from Jeff (Rainier Precision). Probably should save the disc from the old washer. May not be necessary, but seems it would make the washer more durable.

Dale
Brigadoon #54