Deck Targeting

Deck Targeting is a process of making sure the shape of a vessel in the water is the same when it is blocked on land.  Today’s lightweight, keel-less fiberglass yachts have a tendency to flex and “hog” or “sag” when lifted out of the water.  We have seen large yachts such as Azimuts flex as much as one inch in the transom if not blocked properly.

If the vessel requires any running gear work, and there is a chance that a strut or engine alignment is needed, it is imperative that some yachts be Deck Targeted before haul out.  As you can imagine, trying to get a strut and engine alignment within a few thousandths of an inch is impossible if the yacht is blocked on land with a hog that puts the strut one half inch out of her “floating” location.

The modern approach to deck targeting uses multiple lasers strategically placed on the deck or in the engine room.  A skilled targeting technician will understand how to position the lasers for different types of yachts.  While the boat is in the water, lasers are fixed to immovable objects in the boat; a stern cleat is a good example.  The laser is shot roughly one foot above the deck pointing from the stern forward.  A yardstick is positioned every two feet from the laser moving forward.  At each two foot position the deck is marked with tape and the height from deck to laser is noted on the tape.    Measurements stop around the midship point since we are only concerned with maintaining the yachts shape in the aft section (between the struts and engines).  For some yachts the process is repeated with another laser pointed thwartship to look for twisting.

The yacht is hauled after measureing however, great care must be taken to ensurethe laser is fixed and cannot move.  If the laser is bumped or moves then all measurements are lost, the yacht needs to be refloated and measurements retaken.

Once the yacht is up on keel blocks and jack stands the technician checks the measurements.  If the boat is hogging or sagging it will show in the laser marks on the yardstick measurements.  The deck targeting technician instructs the haulout crew to move blocks or adjust jack stands in order to replicate the same measurements and hull shape noted while in the water.

Unfortunately, not all companies perform this necessary step.  We hear from owners and other yards of boats that vibrate after a lengthy and expensive alignment.  A perfect alignment on land is completely worthless if the yacht assumes a different shape once back in the water.

Not all yachts need to be deck targeted.  Most yachts are stiff enough with construction materials or keel designs.  If you have a lightweight, high-speed yacht or one that is know to flex you should consult your local yard on this option.

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