IMS Racer

The IMS differentiates between racing and cruising designs by using a series of requirements, including headroom, accommodation components, cockpit length and volume, interestingly, the cruising version has the bigger rig, with an additional 33 square feet of sail area.

tank capacities and general stowage capacities. Visually, the cruising versions will have longer and higher cabintrunks and shorter cockpits with coamings.

This IMS hull has a very plumb stem, all business. I think all else being equal, a little more bow overhang would be nice. Bow overhang gives a dryer boat and provides more deck space around the tack of the jib. However, with the way the rule is currently written, we will not see bow overhang on racing boats for a while. Beam is moderate and evenly distributed. The D/L is 113. The keel shows no fillets at either end of the root, and the rudder is very narrow and deep. There is a shoal-draft option.

I think the nicest aspect of the racing version is the deck layout. The basic idea is to keep the crew weight in the middle of the boat where it will not aggravate pitching. Add to this the convenience of arranging it so most of the line handling can be done from the weather side to keep the boat on its feet. Modem boats need to be sailed as flat as possible. Maybe all boats do. The use of a tiller, as opposed to wheel steering, is that it has the advantage of keeping the skipper forward. Plus, a tiller can be lighter than a wheel.

In the racing version, the emphasis on the interior is to place the sleeping off watch centered right around the LCG (longitudinal center of gravity) of the boat to reduce pitching moment. This makes sense in long races but has little effect on round-the-buoys courses. The galley is almost invisible and the head shares the fo'c'sle with the sail inventory. The engine box is right in the middle of the boat.

If this layout is a little austere for you, check out the cruising version. The cruising interior is a conventional layout, with double berth forward and two large quarter berths aft. There is an enclosed head and a nice galley. There is even a nav station and wet hanging locker.

Rigs also differ with the two versions. Both are fractional rigs, but the racing version uses a fourspreader setup, while the cruising version has only two sets of spreaders. The advantage of the quad spreader rig is a lighter stick, but a stick that will require more attention to keep it in column. A very subtle difference in the two rigs is the additional 2 inches of J dimension on the cruising version. I would guess that this difference is a function of some pragmatic structural consideration. The cruising version has 18 inches more P dimension. Interestingly, the cruising version has the bigger rig, with an additional 33 square feet of sail area. The SA/D for the cruiser is 28.6. That's a lot of horsepower per pound for a cruising yacht. The cruiser also comes with a retractable bowsprit so that you can fly an asymmetrical chute.

Holby's construction technique uses the SCRIMP method of resin infusion. Laminating resins are injected into the laminate under pressure. Unidirectional E-glass is used along with Divinycell and balsa cores. The bilge grid uses biaxial and unidirectional fibers over variable density cores. All bulkheads are composite panels.