Early in the new year, we announced the exciting news that Seattle Yachts International acquired Northern Marine, the high-end builder of expedition yachts. With a strong heritage in commercial boat building, the company has successfully launched the dreams of many couples. Serious and rugged adventure yachts with exquisite custom interiors designed and constructed to fit the needs and plans of each yacht’s owners. (Read: https://www.seattleyachts.com/news/northern-marine-is-back

With new ownership and the ability to resume operations, Northern Marine slowly brought back its experienced crew of technicians and craftsmen. The decision was also made to begin construction of a new 57-footer, while efforts began in earnest under the Seattle Yachts umbrella to attract buyers.

Northern Marine’s General Manager is naval architect Stuart Archer, an experienced yacht builder who plans to bring the company back to being top dog in the expedition yacht niche. As a custom builder, Northern Marine works directly with each owner couple, rather than through agents who represent foreign yards, which creates great relationships and often friendships.

“The build process can be just as exciting as cruising to your vacation destinations,” Stuart told me. “The amount of decisions to be made on a custom yacht is endless and can be daunting although some of our clients enjoy the process.

“We can build a yacht from just a cut-out picture or build it like the last one and call the owner when it is in the water. However, for many, the more involved they are in each decision the better. The floor plans, countertops, fixtures, moldings, inlays, and door handles. The process can be fun and enjoyable or overwhelming.

“In each case we start with the general arrangement.”

Without an owner of this new yacht, the company reviewed its previous projects and came up with a reasonable plan for the new boat. It would be a two-stateroom layout, and walnut was selected as the hardwood of choice. Many of the primary systems could be determined up front to get started, while allowing changes to the specifications after the boat is purchased and other changes can be accommodated.

“We have a general arrangement drawing and our systems layout outlined. Now it is time to build,” Stuart added.

The team got started building the hull before the virus nightmare affected Northern Marine and the rest of the world. It had to shut its doors for the quarantine mandated for Washington State. Weeks and weeks went by, but slowly the restrictions were eased enough to bring in small teams of employees to pick up the process and build the hull for Hull Number 6.

Northern Marine uses resin infusion to manufacture its fiberglass parts, which include the hull, superstructure, flybridge, boat deck, mast, hardtop, and hatches. The company has enormous success with this building technique, taking advantage of the newest technology made available by nearby Boeing Corporation. This is state-of-the-art boat building, and remarkably efficient, consistent, and accurate. It also scored high marks for its reduced emissions and environmental impact.

For a basic description of the resin infusion process, dry laminates are placed into a mold, the number of layers and core materials carefully arranged for the best possible strength and rigidity. Then the laminates are covered with ply release materials and channels which will allow resin to flow, and then the mold is encapsulated in a big plastic bag. Hoses and valves are attached at strategic points along the bag and a pump generates a vacuum to suck out all the air. Once a controlled vacuum pressure remains steady over a period to ensure there are no leaks, the crew opens the valves and resin is drawn by the vacuum through the network of hoses to saturate the dry laminate and coring materials. This guarantees there are no voids and creates an accurate ratio of fiberglass to resin. When the resin solidifies, the result is an integrated rigid composite part or component. Or hull.

Unlike traditional boat building, everything is carefully engineered and lmeasured to ensure the highest quality of fiberglass construction, and Stuart said they can achieve an ideal ratio of 70 percent fiberglass to 30 percent of resin. (Done by hand, using brushes and rollers, it is impossible to get that ratio of strength. Fiberglass provides strength, not resin.)

fiberglass done by hand on northern marine 57 

About a third of the dry laminate has been laid in this image, with core material going in. Northern Marine uses several different types of core, including Corecell, Divinycell, perforated core, even balsa. (Unlike traditional worries of using balsa as a core material, where it can rot if the laminate is damaged to allow water intrusion, resin-infused balsa can’t rot, has proven to be a great material that offers superior sound deadening.

Note the colored Kevlar in the bow area, sandwiched between the middle and outer layers of laminate, to protect the front 25 percent of the hull in the event of an impact.

green sheeting going down in hull

All laminate materials are in place, next comes peel ply, a light green sheeting that is easily removed after the resin kicks off. It leaves a finished fiberglass surface ready for the secondary bonding of bulkheads and tanks as the textured surface after the peel ply material comes off allows good bonding.

The darker green material is a flow media that lets resin flow easily over the surfaces.

Enka Channel 

On top of the flow media goes Enka Channel, a four-inch wide, three-dimensional filament strip that enables fast resin flow in all directions, and hoses attach directly to it. The flow media has a high resistance to compression as the resin flows, and the Enka Channel won’t leave imprints in the cured laminates.

entire mold covered in plastic 

The entire interior of the mold is then covered by plastic, as if the entire hull was put in one big bag. A vacuum of one atmosphere is maintained to monitor for any leaks of the bag or where it is attached.

valves and inlet hoses 

Valves and inlet hoses are then installed, and Butyl tape used to eliminate leaks, which are most common around the elbow fittings and either side of the valves.

resin infusion process 

Let the resin infusion begin! All of these hoses come out of one of three garbage cans, filled with resin. Once the valves are opened, resin flows quickly through the hoses as vacuum pressure pulls it in. Operators start the resin flowing at the keel and work outward. You can see the resin has infused about halfway up the sides of the mold.

This process happens so quickly that each garbage can must be refilled every couple of minutes, from the blue supply hoses which draw resin from the 17 drums of resin needed for this 57-foot hull.

The two upper garbage cans take over to finish the upper portion of the hull as they need less vacuum to reach those areas.

When it is all done, there might be four or five gallons of resin left over, and perhaps three percent of the resin left in the tubes.

What is striking is the lack of smell. If you have been around fiberglass construction, it is a strong and pungent odor, but with resin infusion everything is sealed. Stuart Archer said one day they were doing a hull while the yard was getting ready for a chicken BBQ, and the building smelled like chicken! No need for protective gear, gloves, masks, or oxygen down in the hull. This is environmentally friendly and no longer the nasty chore of the past.

bags removed from hull 

The next day, the crew removes the bag, hoses, peel ply and other materials. What’s left is the clean, new hull.

foam stringers infused 

The crew next tabs in foam stringers, which will also be covered and infused to the hull.

resin infusion begins 

Almost ready to begin infusing the stringers onto the hull. The techs monitor the vacuum to make sure there is no pressure drop. It takes an hour to complete the stringer infusion.

They sure do use a lot of hose, but it is a clean and environmentally safe way to build fiberglass parts.

gelcoat on the northern marine 57 

The shiny white gelcoat of the new hull comes out of the mold.

Building the Other Structures

building other structures 

The yacht’s superstructure gets the same treatment as the hull. What you are looking at is the top of the boat in the mold, but upside down. The wide edges of the mold are the side decks. Tubes are installed four to six feet apart, and the Enka Channel is set 24 inches apart on vertical surfaces. It takes a couple of hours to infuse the superstructure.

finished superstructure 

The finished superstructure out of the mold. Wood inserts are where windows will go.

flybridge of northern marine 57 

The flybridge is more of a challenge to get out of the mold due to its many compound surfaces.

laying laminate over core material

Laying laminate over core material on the inside skin of the upside-down boat deck. The black core material is high density core for the crane base.

dry fitting the flybridge 

Dry fitting the flybridge to the top of the pilothouse, with the boat deck behind it. In addition to these parts, the crew also builds a mast, hardtop, and hatches using the resin infusion process.

northern marine 5706 wide body 

Northern Marine 5706 will have a widebody layout as seen in this picture of the glassed-in boat deck and flybridge.


Ballast, Interior Tanks, Bulkheads, and Machinery Go In


Ballast in Northern Marine yachts comes in the form of copper-coated lead bullets. In this container are 3,000 pounds of bullets. They come in many calibers and shapes, rejects and overruns, sourced from Idaho.

two ballast spaces 

Straddling the centerline graywater and blackwater tanks, the two ballast spaces each get 6,500 pounds of lead, for a total of 13,000 pounds. The small size of the bullets lets them settle tightly into the spaces, maximizing density, and the two areas are then glassed in place before a floor is installed over the entire area.

The fin stabilizers are in place. Note the fiberglass drip tray to catch any oil leaking from the actuator. Nice touch.

main bulkheads 

Main bulkheads are then glassed into the hull, and two fuel tanks are built outboard of where the engine will sit. The hull is not part of a fuel tank, but the side of each tank follows the hull shape exactly, maximizing volume.

looking down into engine room 

Looking down into the engine room, and the beautiful, 325hp John Deere 6090 diesel engine sitting on its bed. Baffles in the port fuel tank are clearly visible at the bottom of this photo.

engine room with fuel tanks 

Another view of the engine room, with the fuel tanks completed. Each tank gets tested to 3psi.

Note the PTO off the back of the engine, which will power the hydraulic stabilizers and other hydraulic needs while underway. The through-hull fitting for the sea chest can be seen just aft of the engine.

sea chest through hull 

More detail of the sea chest through-hull. The butterfly valve that opens and closes the sea chest is clearly visible.

t-shape sea chest 

This is a new design for Northern Marine. The T-shape of this sea chest allows for up to eight systems to draw seawater for various needs, such as engine and generator cooling, hydraulic cooling pump, and watermaker. This boat will have two spare outlets.

In addition to providing multiple dedicated sources of raw water, what is truly outstanding about this design is that this sea chest has a Lexan cover on top, above the waterline. It will be a simple task to open the top of the sea chest and clean out any debris or growth.

northern marine 57 john deere engine 

Another view of the PTO off the back of the Deere engine. The other equipment over the three-inch shaft is the yacht’s hydraulic drive for “emergency” propulsion. It will be powered by one of the ship’s 17kW generators to push the boat at five knots, 24/7. Get home drives are seldom used in the real world, and Stuart Archer can only think of one instance where it was needed on a Northern Marine yacht, when the owner got too close to a waterfall…operator error.

However, Archer did say that owners use them occasionally to make sure they work. In one instance, the owner got up to make coffee, and decided to move the boat, so he engaged the hydraulic drive and drove off, without the main engine.

master staterooms 

Looking down at the master stateroom, with floors over the ballast and tanks we saw earlier. The copper strap from the stabilizer connects with other straps to a large zinc at the transom, which is easily viewed for general inspection.

New on this yacht are four-foot-tall deadlights to bring sunlight into the stateroom, which is a fabulous idea. So many yachts have dark accommodations when located midships. The deadlights will have one-inch-thick glass, and not to worry, they will have inside covers, just in case. This is big ship, ABS-standard thinking.

steel keel 

A steel keel shoe runs the full length of the boat to the bulbous bow, for grounding protection. The metal bracket holds the keel shoe to the hull. Note the lubricating hole for the cutless bearing, and stern thruster. Stuart said they faired the hull on this yacht at the stern to improve laminar flow of water just ahead of the 42-inch, five-blade propeller. This will keep cavitation to a minimum.

matching generators

A fiberglass liner with two matching 17kW generators mounted. One generator is dedicated to house electrical loads. The generator with the PTO will assist with hydraulic systems. While the main engine will normally power hydraulics, such as the stabilizers underway, when coming into a new port at night, and the owners want full power to bow and stern thrusters as well, the generator provides that additional power so all hydraulic systems are operating at 100 percent.

Such systems can be set up in many ways, of course, and it is common to see a third, smaller generator (which is very quiet) to run the air conditioning at night. Northern Marine can design systems for any possible electrical or hydraulic requirement or load management capability.

Hull Number 6 is now ready to come together. The pilothouse, galley, and saloon are roughed in, and the superstructure can now be placed on the hull, as work continues.

We will continue to follow the fascinating activities as they spiral together to become the next Northern Marine luxury expedition yacht. Stay tuned!