J/125…”A Spectacular Sailing Machine”
The 41 foot J/125 is as close to high performance big-boat sailing one can find in a boat that’s manageable (yes, even with spinnaker) by two or three people. J/125 is like a street-legal Indy 500 car that’s easier to drive than the family sedan. Joy in ownership (and investment) is a function of time spent sailing. Time sailing depends on how easy it is to be off “on the spur of the moment” inspired by a beautiful day without having to organize 8-10 crew.
Easy to Go Sailing – How easy? Throw off the cover and hoist the mainsail on slides from the cockpit using a 2:1 halyard purchase. Cast off and sail faster under mainsail alone than most boats under full canvas. Unroll the jib and fly upwind. Ready to really take off? Pull out the retractable carbon bowsprit. Hoist the spinnaker in its sock. Then from the cockpit, slide the sock up the sail to deploy the spinnaker. Trim the sheet. Hold on to your hats!
To jibe, cast off one sheet and pull in the other. No need for anyone on the foredeck. To douse the spinnaker, cast off the sheet and pull the sock down over the sail from the cockpit. Stow when ready. Can you imagine the surprise of other sailors as you fly by them in 15 knots of breeze doing 10-12 knots?
Getting the Gun – One of the thrills J/125 owners experience frequently is being first-to-finish and getting the gun. The local crowd ashore assumes, as in other types of races, being first across the line determines the winner. J/125 upwind target speed is 7.8 – 8.0 knots. 10+ knots downwind is a daily occurrence. In fact we know of no other boat of its type and length that’s faster. Finding crew for weeknight and Saturday races is hardly a problem when you’re first to the party.
Stability & Seaworthiness- The sense of solidity and power when sailing the J/125 is explained by J/125’s extraordinary stability index of 143 degrees with a stability curve ratio of positive to negative areas of 12.5:1. This greater stability is combined with a balanced hull-form with proper amounts of reserve buoyancy forward, capable of safer & controllable higher-speed planing offshore in large waves and providing a wider steering groove upwind for sustained peak performance by average helmspersons. No IMS rule-inspired hull form can match the high 4.72 length to beam ratio of this sea-kindly yacht nor the reserve buoyancy designed into her bow sections. High length to beam ratio insures straight tracking in rough seas and light steering loads. Sailboats with fine bows and full midship sections are more difficult to balance and more likely to spin out of control in big waves.
What’s Unique About J/125’s Construction? The J/125 is built to ABS offshore specifications by TPI Composites using the SCRIMP resin-infusion process. Tests conducted by the US Naval Surface Warfare Center at Carderock, MD established that the properties of laminates produced by TPI’s patented SCRIMP resin-infusion process are superior to low-energy pre-pregs used by many custom boat shops and twice the strength of hand lay-up.
J Boats was hesitant to enter the lightweight race boat market until something like SCRIMP/Carbon technology became available. In our judgment, SCRIMP construction greatly reduces the chances of warranty claims due to laminate failures resulting over time from pounding into waves and/or rig tension or ballast loads.
SCRIMP Process- The entire laminate is placed in the mold dry. A high vacuum eliminates any air voids, then resin feed tubes draw in only enough epoxy to “wet” the laminate. This is the TPI patented SCRIMP resin-infusion process. The last step in the process is to post-cure the hull and deck at 140 degrees in a closed oven. As can be seen from the chart, SCRIMP laminate properties in terms of compression strength, flexure, and tension are twice the strength of hand lay-up and significantly stronger than low energy (vacuum bagged) post-cure pre-pregs. There is no entrained air in a SCRIMP laminate. 1% void content reduces flexural strength by 10%. Note that 50% fiber content in a carbon laminate equates to 67% carbon/33% resin by weight. See the comparison of composite properties of low cost fabrication methods in the chart above.
Weight of Construction- after subtracting weight of keel plus 1000 pounds of rig, engine and hardware, J/125 at 2700 pounds is as much as 1500-2500 pounds lighter than competitive designs. Not all of this has to do with the J/125’s narrower beam.
Hull & Deck Laminate Design- of the J/125 is stronger for its weight than E-Glass/epoxy laminates using slit CoreCell foam. J/125 uses epoxy with a combination Kevlar & E-Glass for the outer skin with two layers of carbon fiber (bi-axial & unidirectional) for the inner skin. The higher strength of these exotic materials allows a thinner, lighter skin than the equivalent E-Glass structure.
The CoreCell A500 and A600 foam cores of the J/125 laminate is further processed for strength and to save weight by:
(a) thermoforming to the shape of the boat in a second set of tooling to avoid having to slit the foam to bend it to the shape of the boat, and
(b) perforating on 2″ centers to form epoxy rivets between hull skins. If the core is slit to bend to the boat, then either resin fills the slits and adds weight, or there are air pockets in the laminate which reduce strength.
Keel- The keel design of the J/125 is unique to this size boat in three ways important to the owner:
(1) The strut is cast of an NAB (nickel/aluminum/bronze) alloy rather than from steel/iron which can rust causing maintenance headaches,
(2) The integral flange of the strut has a six square foot interface with the hull in two parallel rows of ten 7/8″ stainless bolts. And,
(3) Built into the leading edge of the keel as an option is a San Diego style kelp cutter.
Built to: Hull #16
Last Model Year: 2003
Articles & Reviews
J/125 Sailing Reviews & Articles
Winning The Chicago-Mac 1999
By Jay Lutz
Back in May (’99) my friend and customer Mike Rose of Houston called to say that he didn’t have the time to do Block Island Race Week. We had been preparing for the regatta since Key West R.W. and his new J/125 Raincloud was a blast to sail. “What regatta can we do later in the summer?” Mike asked. “What about the Chicago – Mac Race? I heard it’s a lot of fun” So off we went, six Texans and a couple of Yankee’s.
Flying South for the Winter on a J/125
By Jeff Johnstone
Jeff Johnstone caught up with Dan Mullervy of Annapolis and heard about his recent experience crewing aboard the J/125 STRABO. The story begins with the delivery down the coast and winds up with STRABO winning Class A in the Fort Lauderdale to Key West Race. Read more here….
J/125 PHRF/Sportboat of the Year
Over the last five years, sportboats have evolved into highly refined sailing machines that offer incredible performance with a touch of offshore capability. This year, the competition in our PHRF/Sportboat category included the J/125 the One-Design 35, the Van Gorkam Mount Gay 30, and the Quest 33. All are remarkable boats rampant with innovation, but the long, lean, and mean J/125 simply blew away its competition.
TEST-DRIVING THE J/125
By Tom Leweck- Scuttlebutt Sailing Newsletter
Sure—I’ve heard all those stories about people who are too dumb to come in out of the rain. Yet on Tuesday afternoon there were seven of us sailing in the rain on San Francisco Bay. And while I can’t speak for the others, I was having a blast. How’s come? It was because I was taking my first test-drive in the new J/125. Read more here….
J/125: Innovative speedster
By John Kretschmer
The J/125 makes you feel young all over again. Remember sailing a J/24 for the first time? The boat seemed to defy gravity, or at least friction, as it surfed down waves in perfect control, blowing by 35-footers in the process.
This new 41-foot flyer, designed by Rod Johnstone, delivers a similar thrill in a larger, brilliantly conceived package. Innovative designs and engineering excellence are certainly the key factors in J-Boats’ongoing success.
Another reason the company often seems one step ahead of the competition is that it takes consumer research very seriously.
- ft/lb m/kg
- LOA 41.00 12.50
- LWL 37.00 11.28
- Beam 10.60 3.23
- Standard Draft 7.90 2.41
- Standard Ballast 4,646 2,107
- Displacement 8,350 3,788
- Diesel Aux. Engine 28 hp 28 hp
- 100% SA 781 72.56
- I 49.00 14.93
- J 14.80 4.51
- P 45.50 14.17
- E 18.00 5.49
- SA/Dspl 30 30
- Dspl/L 74 74