Im thinking of buying some used lead shot and making a 150-175lb centerboard. That would make a huge difference.
You'll will almost certainly need to re-engineer the centerboard trunk if you add 100 or 150 pounds to the 25-50 (?) pound centerboard. You might need to replace the mast and the standing rigging too, due to the loads the rig will carry because of the higher righting moments generated by the keel. The mast wasn't spec'd to handle the higher forces, and it might buckle. Chain plates may not be adequately anchored for higher loads. The hull might flex under higher loads, makign it difficlut to keep the rig tuned.
In short, it might be better to buy a different boat than to modify this one. Certainly, it lower the market value if you start changing the basic structure of the boat without professional advice.
And nothing is more critical to the engineering than the righting moment of a boat. Virtually everything else on the boat is engineered to handle the loads generated by the righting moment with a high margin of safety.
Or, you could attach some lead ballast in the bottom of the cockpit. And then reduce max crew weight accordingly.
Or, you could sail without going beyond the limits of the boat. Either don't go sailing with guests who aren't able to switch sides or reef the sails when you have guests who aren't able to switch sides.
Honestly, aside from the weird plastic that cracks too easily, I think the H170 is a great family daysailor for sheltered inland waters. For its price and weight, it's a great boat. A lot of inland sailing schools have fleets of them.
But you don't have to take my word for it, Here's a review by Bob Perry, renowned naval architect.
http://sailingmagazine.net/article-461-hunter-170.html
Hunter 170
1999 November 10
By
ROBERT H. PERRY
When I first set out to test sail the Hunter 170, I have to admit I wasn't quite sure what to expect. My previous experience with Hunters had been on larger boats during extended cruises, albeit very comfortable ones, and not just a quick afternoon spin on Biscayne Bay. I was interested to see the Hunter approach in the context of a daysailer, as the boat is billed as a no-nonsense, affordable family boat. I was pleasantly surprised during my first encounter with the new 170.
The Hunter 170 is a joint venture between Hunter Marine and JY sailboats, which combines simplicity and comfort with toughness and performance. The boat and rigging are set up to be as simple as possible, allowing the owner to rig the boat and go sailing very quickly. The mast is light and can be put up by one person, although it's easier with two. The jib is set up on a roller-furling system with the sheets led back to swivel blocks in the cockpit. The mainsail is simple as well, with only one line necessary for the outhaul and a main halyard that is easily accessible on the mast from the cockpit. I was told that reef points for the sail are an option, but our test boat came with only two settings for the main-either all the way up, or all the way down. The mainsheet is placed conveniently near the helmsperson to trim while driving, but the block swivels so it can be trimmed just as easily by the crew. This simplicity results in a clean and uncluttered cockpit, making movement about the boat very easy.
The standard version of the Hunter 170 has a centerboard that draws 4 feet, 6 inches when fully lowered. It is built with a counterweight so it doesn't require a 270-pound linebacker or a maze of blocks to pull it back up. Combined with the swing-up rudder, landing on the beach or parking on a sandbar is a breeze. With the centerboard up the boat draws only 6 inches. An added bonus is the open transom, which allows for easy access when swimming or boarding. Another option is a 2.5-horsepower outboard, but we decided to go on our test with sails alone. With a blue sky, and about 15 knots of breeze, it couldn't have been a more perfect day for sailing. When I met up with Eric Macklin of Hunter Yachts at the Miami Yacht Club to take the boat for a spin, Macklin had the boat on the trailer waiting in line with the mast already up at boat ramp, and within minutes of our arrival, we had the boat floating at the dock.
Macklin gave me a verbal tour of the boat, and as I got myself acclimated, we sailed out into the bay. The boat comes with a canvas-covered storage area in the bow and sheet bags mounted at the mast. This is an excellent place to keep gear, life jackets, coolers, or other stuff out of the way. As I leaned forward to take the dockline off the bow, I found the one thing that I didn't like about the boat: It was a long reach from the cockpit to the forward cleats, and the canvas cover doesn't support a person's weight when leaning forward. This minor awkwardness aside, the canvas can easily be removed by unsnapping it if you need to reach forward, which is what I did.
The Hunter 170 turned quickly through the wind, and I found that, although a stable boat, it is still sensitive to weight placement, and in a breeze, you definitely need to be on the high side.
After the third tack, Macklin said, "Uh, you don't have to duck. That's one of the best things about the set-up." Of course, he was right and I had to laugh at myself. Years of sailing Lightnings had taken its toll-I was unconsciously ducking my head through each tack, even though the boom was a good three feet above it. In addition to the generous headroom, the clean layout of the cockpit can easily accommodate six people. The contoured benches were also very comfortable as we sat back to enjoy the view of Miami from the bay.
Upwind in the puffs, the wind was strong enough that we had to play the sails to keep the boat under control. Had we not been pushing the boat hard, we probably would have rolled up the jib and sailed under main alone, since with the fractional rig, the main alone provides plenty of power in breezier situations. With the boat heeled, I found that Hunter had the foresight to incorporate a toerail down the center of the cockpit floor. Sailing hard upwind with my feet now firmly planted, I noticed that the boat did not have a heavy weather helm even when it was fully heeled over. I was able to turn the boat up and down with the flick of the arm.
We cracked off slightly onto a reach, and the boat took off. The wide beam provided plenty of stability. Our test boat did not come with the optional asymmetrical spinnaker, but this is an option I would recommend for the sailor looking for lots of fun off-the-wind. We tested the roller-furling jib, and I found that, as with everything else on this boat, it was very easy to use. The line used to roll up the sail is led back to the cockpit and conveniently located next to the cleat for the jib sheet on the starboard side. Macklin suggested that the jib is easier to roll up when sailing dead downwind. The technique also made for a tidier-looking furling jib.
The 170 is built using Hunter's Advanced Composite Process, known as ACP, which makes the boat light, durable, and virtually unsinkable. The technique begins with a weather-resistant polymer on the outside and a knitted fiberglass fabric on the inside. A urethane foam is then injected in between and the resulting sandwich heated and vacuum formed, making it extremely strong and solid. The process is actually environmentally friendly, since the plastic used in the construction is recyclable. In fact, scraps from the building process are recycled on-site at the factory.
The exterior plastic is scuff-resistant, which makes the boat easy to clean and maintain. According to Hunter Marine, since the layers are bonded together and not laminated, delamination isn't even a possibility.
The foam core is also very light so that the boat weighs only 480 pounds. For the skeptics out there, Hunter stands behind the product and puts its money where its marketing is-the hull has a five-year warranty.
The 170's solid construction and straightforward layout make it ideal not only for beginners, but also for more experienced sailors who want a fast, simple boat to take out just for fun. Hunter has taken great steps to ensure that the 170 has a wide appeal by balancing durability and performance for a high fun factor. As is the case with so many of it boats, the company seems to have found the right combination.
