The design of the Sentijn has its origin in the late nineties. To call the Sentijn 37IQ an 'old friend' doesn’t do justice to the new version of the Dick Koopmans design. A lot has changed. The sail plan, the interior, the cockpit and the hardware are substantially altered. The addition IQ (Innovative Quality) stresses, however, mostly invisible changes. The new Sentijn is built in a very modern way. The result is a yacht which combines its original design and modern requirements.

All structural calculations were performed to Lloyds standards. The most dramatic improvement is the construction and lamination of a sturdy galvanized steel frame keel. It's filled with closed-cell foam. This prevents condensation and the possibility of corrosion has been ruled out. Two ribs of the frame are extended and continue to just below the chain plates. A stainless steel spanner connects the chain plates to the keel frame. Thus the forces on the rig have optimum support.

The hull is made ​​of vinylester, a synthetic material with many advantages. Vinylester is stronger and more elastic than polyester, it is more scratch resistant and - most importantly - impervious to osmosis. The yard builds the Sentijn 37IQ with vacuum infusion. This method ensures optimum control over the construction process. The resin is everywhere and there is no air entrapment, from which the strength and stiffness benefits. Vacuum infusion results in a lighter hull, because the resin is properly dosed. The hull has a core of 20 mm Airex foam, where according to calculations, 16 mm would suffice. The thicker core provides greater strength, stiffness and insulation. Solid laminate is used in high stress areas and under the waterline.

All bulkheads and lockers are laminated to the hull and to the deck.
The deck is bonded to the hull with polyester glue, then bolted and laminated.

The keel of the Sentijn 37IQ has also been altered. Its draft is 2.05 m and it has an L-shape with a lead bulb. Compared to the original version, the new keel has less wett surface and slightly less weight. The point of gravity is however lower and this is beneficial for the initial stability. Keel and construction provide a weight saving and the engine contributes to this. The modern four-cylinder Volvo Penta diesel is more compact and lighter than a three-cylinder diesel from ten years back. Moreover, it runs smoother, more silent and has lower CO2 emissions.

The cockpit is ergonomically improved. The fore part of the cockpit floor is lowered 6 cm, which guarantees more pleasant seating. The cockpit is spacious, but you can brace yourself properly when the boat heels. Because a bridge deck is missing, the entrance to the cabin is easy. The threshold is high enough to keep water out.