Building a bulletproof boat
Posted on 01 November 2010
Written by Eric Sorensen
In 1986, work began in California on the hull that eventually became Lions Whelp, the 65-foot Alden-designed schooner that Phin and Abbot Sprague bought more than a decade later and outfitted for offshore cruising. The hull was built with strip planking and cold-molded wood, but construction came to a halt, and the boat sat in the sun with the bilge full of water for the next 12 years. That's how Phin and his brother found her in 1998.
They'd been searching for a schooner, a design well regarded for its seaworthiness and ability to take heavy weather and without artificial design compromises imposed to meet class restrictions. The boat was just what they had been looking for - minus the rot around the garboard caused by the standing water - so they purchased the hull and had it trucked across the country to Portland, Maine, where it sat for another year and dried out. Meanwhile, Phin started to design the interior and deck arrangement with Niels Helleberg, the boat's original designer at Alden.
A key concern for the brothers was hull integrity. "When you're doing 9 or 10 knots at night there's no way you can see a log or container just under water ahead of you. It's a probability issue," Phin says.
He points out that right after a hurricane in 2003 a whole load of telephone poles came off a container ship in the vicinity of Bermuda. The poles were 120 feet long and 3 feet thick, plenty big enough to sink a yacht. There was also a sea buoy loose in the area and that buoy was 10 feet in diameter.
"There are lots of hazards to navigation floating right below the surface," Phin says. "Either you're going to sit there scared out of your wits, or you build the boat so you have a higher probability the boat will be safe."
Preparing the boat for cruising in today's junk-strewn oceans shaped the work to come on Lions Whelp. "To repair the rotted hull above the keel," Phin says, "we sliced the boat in two horizontally and replaced everything from the keel up to above the turn of the bilge - the wooden floors, planking and lower sections of the ribs."
Once they had repaired the garboard area, they built test panels. The first one was built the same as the original hull and the other two were backed by 3-inch-thick sections of Nida-Core. Their engineering work consisted of dropping a 150-pound section of railroad track on top of the panels from a height of 30 feet. The impact cracked the first panel. "Made quite an indent in it," Phin says. "Then we did the same thing with the Nida-Core sections." (Nida-Core is a structural plastic honeycomb core material.) The indentation was barely visible and there was no structural damage. "We dropped the rail from 30 feet a number of times, still no damage," he says.
"The problem with a conventional plank-on-frame hull is that you have the planking on the outside of the ribs and the ceiling on the inside, with a void that's the thickness of the ribs between them," Phin says. "If you puncture the hull planking, you can't get to the damage to stop the leak because the ceiling is in the way."
They bonded 3-inch-thick Nida-Core - the same thickness as the ribs - to the planking with WEST System epoxy. "Then we glassed over the Nida-Core from the inside with epoxy 10-08 glass creating a smooth surface on the entire inside of the hull, from sheer to sheer," Phin says. "Next, we epoxied a 5/8-inch fir tongue-and-groove ceiling over everything and painted that. We created a monocoque [one piece] structure, a continuous I-beam that added a great deal of strength and impact resistance to the hull, as well as thermal and acoustical insulation."
The 3 inches of Nida-Core lining the inside of the hull also added a lot of positive buoyancy - not enough to keep it afloat in a worse-case scenario, but enough to slow the flooding in the event the hull is punctured and repairs are under way.
"The boat displaces 84,000 pounds and we've got 54,000 pounds of positive buoyancy in the hull as it's built, between the wood and Nida-Core, so it could sink, but it's much more resistant to sinking than conventionally built wooden or fiberglass boats," Phin says.
"If swimming is a poor option, the first rule is to keep water out of the 'basement,' "he says. "So failing to prevent that introduces a whole series of cascading problems that could easily sink the boat."
The wood-epoxy structure was further braced with 3/8-inch stainless-steel floors with strapping bent over the wooden frames as stiffeners integral to the mast steps, and heavy stainless-steel engine beds and I-beam mast steps.
The yacht is finished off to a very high standard, with joinery as good as any I've seen. The mahogany interior and deck furniture were built at Belfast, Maine, boatbuilder French and Webb, then trucked to Portland and installed in the hull.
The yacht's systems are thought through in minute detail, including their accessibility. Major components are designed for rapid removal; they're even designed to fit in the available cabin space while work is being done to the machinery. The brothers spared no expense building the boat and it shows in the attention to detail everywhere.
Other than a rock or reef punching a hole in the bottom, one way for water to get into the boat is through holes put there by the builder - through-hulls or shaft and rudder stuffing boxes. The original design had 28 through-hulls, so they reduced that to nine by using manifolds on the inside, effectively creating sea chests. Think of it as increasing the odds against a fitting failure. Also, there are no through-hulls their 220-volt, 380-gallon-per-minute Piranha dewatering pump can't keep ahead of.
The carbon fiber masts are finished to look like wood but are hollow, stiffer and lighter than wooden masts would be, and they serve as a ventilation duct for the engine room. Sails are raised using block and tackle, not powered winches.
If this were an ocean-rated commercial vessel or a Coast Guard heavy-weather rescue vessel, it would be divided into separate watertight compartments to make it more resistant to sinking with a hole in the bottom. But this is a yacht and true subdivision would require four or five watertight bulkheads up to the main deck level, impractical for a pleasure boat.
What Lions Whelp does have is a forward collision bulkhead, all that positively buoyant Nida-Core and the high-capacity pump that can keep ahead of a single through-hull fitting or hose failure. All these elements serve to shift the odds more in the favor of the boat and crew in an extreme situation.
Propulsion is a 120-hp Perkins, and Lions Whelp can do 8.5 knots on just the engine. "So what we do is think worse case, such as how much fuel would it take to go 628 miles from Newport to Bermuda under power alone," says Phin. "That's what we plan on then. You have a great big target on your back when you're heading for Bermuda in November or anywhere else far away. You do not want an intersection between that target and the low that's coming along and you really have to hustle and plan to stay ahead of the low. You want to know that target's there on your back. You need to feel it. You don't leave port unless you know your boat can take the consequences of meeting that low."
Since launching Lions Whelp in 2003, Phin has put 20,000 miles on her, sailing from Maine to the Caribbean and Bermuda and back a number of times. Currently under cover in storage, Lions Whelp is for sale, a victim of the economic conditions the country has been in for the last two years.
For information, go to www.portlandyacht.com.
This article originally appeared in the November 2010 issue.