SHANNON 53 HPS HULL #4 CONSTRUCTION
STAGE IV
(CLICK ARROWS BOTTOM RIGHT AND LEFT FOR SLIDE SHOWS)
DECK MOLDING
#1 The first step in the process of molding the deck of the Shannon 53 HPS is to wax the deck mold. The deck mold is a negative replication of the deck, and the orange color on the inside of the mold is tooling gelcoat. The most significant feature of the Shannon 53 deck is that it is one piece. One piece of fiberglass is much stronger that several smaller pieces of fiberglass that are taken out of several smaller molds and then laminated together. Where these pieces of fiberglass parts are glued together, the joints are called secondary bonds, and these joints are never as stronger as one solid piece of fiberglass. Almost all production motorsailers, raised salon and pilothouse boats use multiple piece decks as it is much easier to laminate several small pieces, then glue them together. What happens long term is that the joints start to open up after years of stress, which shows up first as cracks in the gelcoat, and eventually leads to delamination which is costly to repair. While it is harder to lay-up and handle, the Shannon 53 HPS deck is one big structure, and it makes for a better product that will outlast the decks of all competitors.
#2 Here are the materials that will go into the deck for Shannon 53 HPS #4 – drums of resin, rolls of laminate, pails of bonding mastic, boxes of PVC foam core, etc. No cost is spared in the state-of-the art high tech composite core deck specifications.

#3 The first day of the deck layup. The light gray color gelcoat chosen by the owners has been applied in the areas of the diamond pattern nonskid and the white gelcoat follows on the smooth surfaces. A layer of mat followed by a layer of Coremat to prevent print-through of the roven is being laminated over the gelcoat. One specific tool for fiberglass deck production that is NEVER used at Shannon is a chopper gun. A chopper gun takes strands of fiberglass material, chops them into little bits and then sprays then on the inside of the deck mold with a premixed amount of the resin and MEK catalyst. One man could

spray a layer of chopped fiberglass into the Shannon 53 HPS mold, while it takes the five man Shannon crew eight hours to apply about the same amount of laminate. This savings of about 40 man-hours in labor is very important to a production boat company, but the layer of chopped material in production fiberglass decks is filled with air that leaves voids that weaken the laminate. In addition, it is difficult to control the flow of material that comes out of the chopper gun, so a too thick layer can make the deck unnecessarily heavy, and a too thin layer can make a deck weak and unsafe. The term “hand laid up” refers to the fiberglass lamination process used at Shannon – layers of laminate are applied, wet-out with exactly the proper amount of resin, then firmly pressed onto the previous layer of laminates with brushes and metal rollers. It is very similar to the process of applying wall paper.
#4 Day 2 of laminating. The entire process for the Shannon 53 HPS deck takes 4 weeks – one week to prep and wax the mold, two weeks to apply the gelcoat, laminates and core, and one week for the deck to cure in the mold. A production boat company will take less than one week to manufacture a deck. The production boat companies have to get a deck out of the mold quickly, so they put on many layers of laminate in one day while Shannon only puts on one to three layers per day. The problem with putting too many layers on in one day is that there is not enough time to roll out every square inch of laminate, inevitably result in voids compromising the deck structure. Also, the exotherm curve of curing resin causes enough heat to be produced by multiple layers put on in one day so that the last layers crystallize and even catch fire, which is a very bad thing. The fire is put out with water, additional layers of laminate are put right on top of the bad laminate, so this problem would not be obvious looking at the finished deck. It would only be apparent when the boat was several years old and the deck started to delaminate. This can never happen with the slower molding process used at Shannon.
#5 On the fourth day, layers of 1808 biaxial roven are added. If you look close you can notice the marking on the white rolled material on the foredeck. To make a deck at Shannon, several hundred specific pieces of different types of laminate (mat, roving, Coremat, etc. ) are cut to exact sizes to be places into locations as engineered by Walt Schulz. Over the years, there have been many more failures in production boat decks than hulls because decks can receive the force of several tons of water with big breaking seas that never happens to a hull. But that has never happened here at Shannon as Walt makes sure the Shannon 53 HPS deck is as strong as it can be.

#6 Additional layers of laminate are applied in high stress areas of the deck. The laminate schedule of decks in particular have to be carefully engineered, as while a lot of laminate and resin will make a deck

strong, too much reinforcing will also make the deck heavy, and weight up high is bad as it makes the boat top heavy and likely to get knocked down in big wave and wind conditions. The Shannon 53 HPS deck design and engineering continues to walk the line (as Walt has done for the last 36 years) between enough strength but not too much weight.

#7 The initial layers of laminate before the core is installed are complete. The lighter color swirl marks on the laminate are where Shannon’s fiberglass crew has taken hand grinders and roughed up the laminate to give it some “tooth” so that the core will adhere better.

#8 The core is careful fit into place. While PVC core is very strong and light and has great insulating properties for both heat and sound, it does not spread a compression load well. When you bolt some deck hardware to a foam or balsa cored deck, the tightening forces tend to crush the core. So at Shannon, in areas where deck hardware is located (like the foredeck and bulwarks), we substitute Penske board, a very expensive black glass fiber substrate that has similar properties to foam core but will not crush when hardware and equipment like cleats, windlasses, stanchions, bow rails, genoa tracks, etc. are installed.

#9- The lighter color PVC core has been installed and the next layers of laminate are starting to be installed. Walt Schulz will be yelling at Joe Arrial for not wearing his protective suit and mask. The core is set into a polyester mastic called Corebond. Over the years, Shannon has experimented with both the vacuum bagging and resin infusion methods of fiberglass deck production. We have concluded that these methods do speed up the process but do not result in better fiberglass part than can be made by a skilled and experienced fiberglass crew.

#10 Looking forward, notice the white inserts where the ½” heat-tempered armor plate glass windows will be installed. The flanges for mounting the windows are part of the deck structure. This is much stronger than glass windows with aluminum frames that are screwed into the fiberglass deck structure.

With aluminum frame windows when big seas crash on the glass, even if it does not break, the force of the water causes the glass to deflect and to pop out of the aluminum frame, letting the waves into the wheel house, which is disastrous. This cannot happen with the Shannon 53 HPS deck and windows. We will show more details on the Shannon 53 HPS windows and installation in subsequent installments.

#11 The last layers of biaxial roving laminates are applied. The deck will now cure in the mold for the next week before it is carefully lifted out of the deck mold and flipped over by a big crane. Then openings for windows, hatches, and companionways will be cut and deck hardware will be installed out before the deck is landed on the hull.

Deck coming out of the mold
Here is the deck for S53 HPS #4 coming out of the mold. It is still winter cold and windy even though the calendar says mid April.
Tom Quinlan and Rick Frazier of Shannon look at the finished deck after it has been flipped over and placed on a trailer
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