SHANNON 53 HPS HULL #4 CONSTRUCTION
SOUND DEADENING AND SYSTEMS INSTALLATIONS
(CLICK ARROWS BOTTOM RIGHT AND LEFT FOR SLIDE SHOWS)

One of the areas in boatbuilding technology that has improved significantly over the last 10 years has been sound deadening. The materials available have advanced so that engine and machinery noise is kept to a minimum. These photos show the new products used on Shannon 53 HPS #4.

#1 Here is some of the Sounddown mylar scrim faced sound foam insulation with sound deadening vinyl sheet

#2 the engine room in the Shannon 53 HPS #4 is lined with aluminum perforated sheet with foam backing. Noise goes into the holes in the sheet and is then absorbed by the foam backing.

#3
An additional layer of vinyl sheet insulation is placed directly behind the aluminum panel. Any sound that goes through the aluminum perforations and the vinyl sheet is then absorbed by the foam insulation.

#4
To truly minimize noise, it is necessary to decouple the sound waves. What this means is that sound that makes it past the insulation has to be stopped from transferring through any wood bulkhead it encounters. Sound can be decoupled by a layer of mastic glue applied between two pieces of luan plywood bulkheads assembled together. When the sound encounters the mastic glue it is stopped from transferring through the two sheets of plywood. If you look close you can see the thin green layer in the middle of the two sheets of luan. Two ½” sheets of plywood assembled together with Green Glue mastic will have better sound insulation properties than one solid piece of 2” thick plywood.

Soundown Co. of Marblehead, MA is the primary supplier of the sound insulation used on the Shannon 53 HPS. It is an interesting company that interfaces the worlds of the university and industry, as the founder of Soundown also is a MIT professor of acoustical engineering.
Here are some other details of the systems located in the engine room of Shannon 53 HPS #4.
#1
The Reverso 12VDC oil changer makes changing the oil in two Yanmar motors and Onan generator easy.

#2
The alternators on the Yanmars are set up with remote voltage regulators with a built-in spare. The voltage regulator is the part of the alternator most likely to fail, and this set-up makes it easy to keep charging your battery without having to change the expensive alternator.

#3
This nice detail shows the stainless steel main salon sole supports, remote engine coolant surge tank, Aquasignal Matupo LED engine light (no heat buildup light like halogen lights and lower amp draw and better light than fluorescent) and a conveniently located 110 VAC outlet.

#4
Here is one of the two 50 gallon holding tanks with the 12VDC macerator pump and a back-up manual pump in case the 12VDC pump fails. On most boats the holding tank only has the 12VDC macerator pump, which has listed in the fine print of the warranty that it will fail only when you have 6 guests on board, and the holding tank is full, with no pump-out dock or boat available as it is either the Fourth of July or Labor Day weekend. With Walt Schulz’s belt and suspenders philosophy, the two holding tanks on Shannon 53 HPS #4 have both electric and manual overboard discharge pumps so this problem can never happen.

#5 AND #6
Moving to the electrical systems, here are the Bass 12VDC/110VAC distribution panels. Note the nice electric color coded, labeled and numbered tinned strand wiring as shown behind the hinged cherry panel doors.

#7
Another nice feature of the Shannon electrical system is the distribution terminals located in various easily accessible locations through the interior. By not running one single wire through the length of the interior it makes it much easy to find a problem in the electrical wiring on a Shannon if one occurs. As an interesting side-note, once the Shannon crew was doing an electric repair on a boat built by one of the supposedly top builders in the Far East. The bow light was out because of a short in the wiring, and when we opened the panel it looked just like a Shannon’s electrical system with all neat color-coded wires. When our electrician got to amidships following the bow light wires based on the color coding, he found that every wire in boat was now blue. This turned which should have been an easy repair into a nightmare. It was a lot easier for this Chinese boat builder to forget doing color coded wiring where you couldn’t see it, but it turned a simple repair into a major headache. This type of work is never found on a Shannon.
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