|Topic Review (Newest First)|
|11-01-2015 12:21 PM|
Re: Long versus short overhangs
This thread has been inactive now for 5+ years but I just found it and have a few things to add. Having owned and sailed relatively long overhang/narrow/deep boats over the past 40 years it seems in this discussion that that a few of the advantages of the design has been either forgotten or misunderstood. First, while the CR uses waterline, beam and displacement, I think that it might be more useful to compare what I call water loading, which is analogous to wing loading on aircraft. With aircraft, the comparison between a light wing loading plane and a heavy wing loading (commercial jet) flying through the same air clearly shows the advantage of higher wing loading. These older designs of course have the higher water loading for the reasons that have already been discussed and I personally find the motion to be the best of any of the designs I have sailed to date. I do think that boats with long overhangs tend to pitch more than the boats with shorter overhangs, but the pitching motion is not all that uncomfortable but definitely does reduce speed, mainly to windward in a chop which is a big negative. With regards to yaw control, I have personally found that when well designed that these types of boats can have excellent control but not for the reasons that were being discussed. Keel hung rudders are certainly less efficient in generating a yaw moment than a detached rudder of the same area, however the narrow hulls generate much less helm than the modern wider designs. In fact if the relationship between the width and the depth of the hull reaches a certain value where the depth curve is more significant than the beam curve, the hull will generate a lee helm…in other words try to yaw against the direction heeled. While this might sound alarming (and can be if taken too far) remember that the rig generates weather helm that increases when heeled and it is quite possible for these two forces to partially or fully cancel which creates a neutral helm. Regardless of the exact relationship, this type of hull design can lead to having a boat that has a very light helm in all conditions. With the helm pressures very light, a keel hung rudder with the heel raked forward such that the rudder actually gains effectiveness when the boat is heeled, plus the fact that keel hung rudders act as a cambered foil and retain effectiveness even when stalled, control is very good on these boats even at extreme angles of heel. I have a couple times been knocked down to 60 degrees or more and still felt that I had good directional control. Sailboat design is fascinating stuff and I enjoy learning all that I can about it. Just for the record, I am now looking at more modern designs mainly for the increased stability but as is always the case I can see that I will have to compromise in some other areas so not sure yet if I want to make a change. Thanks for all of the dated but interesting discussion! James
|10-09-2010 11:33 PM|
Overhangs and cliff-hangers...
D'sestini....glad you posted on that old thread...I had missed it somehow. This was one of the best threads I've seen in here...I for one would welcome anybody who has new angles or anecdotes concerning the albeit wide compass points of this thread to weigh in...
|10-07-2010 05:01 PM|
It looks like an interesting discussion to
wade back through. I enjoy it when some
of these 'classic' threads are dredged back up.
|10-06-2010 09:40 PM|
|puddinlegs||You realize that you're responding to a thread that's about 2 1/2 years old?|
|10-06-2010 09:02 PM|
long over hangs on older boats
Just a comment about long over hangs on older boats. One thing I’ve leant about sailing is that it’s all a trade off whether racing or cursing. If you have the money to buy new “quality” construction modern design you’re going to get the best boat. For those of us that cant buy quality and modern, many of the newer boats mention especially the production boats I would not be caught dead on off shore on, sure the ride might be nice until the fin keel breaks loose, plastic through hulls crack, or core damaged accurse do to continuous slamming do to flat bow sections. It depends on what you’re doing with the boat. Our Block Island 40 isn’t the fastest boat and she will pitch at times. However we don’t conceder reefing in anything under 20 knots, we think about it at 25 and do it at 30. Above 30 we sail under jib and mizzen and general smile. The v shape of the bow on our boat, the Cape Dory , Hinckley Pilot insures no pounding, maybe pitching but no pounding. And in general if maintained are better construction than many new production boats at a fraction of the price. Seriously a Hinckley Pilot at less than half the price of the same size new Catalina, I think it’s a no brainer. If your going to sail the coast of Maine get the Cape Dory or the Pilot, if your racing go modern light with long water lines. If you’re going off shore get the safest boat for your budget. If you’re a trailer sailor well then you constrained by draft.
Just a fact; 20% of sailors will notice the Catalina 380 coming into port, 80% of sailors will notice the Pilot 35 and the other classics beauties come into port.
|05-20-2008 12:18 PM|
|CharlieCobra||We got caught out in some of the nastiest wave action I've seen this past Saturday. We had waves coming from two directions on our beam and 30+ knots of wind. We also saw three rogues running perpendicular to the rest of the waves, that just rode over the normal wave train. This was a clear day, unforcasted event. While we never got pooped, I did have a couple break over the high side onto me (we were heeled at 30-40) for a nice saltwater bath. These waves were straight up the San Juan de Fuca from the Pacific against a strong ebb and with the wind. They were short period, vicious things. I've been out in 60+ and these bastards were the worst I've seen. It didn't help that they were on the beam either. We did a lot of surfing along the faces of these things and the boat was a handful at times. It was a very strange passage.|
|05-19-2008 01:19 PM|
I like German Frers latest designs such as the Swan 45 and the two Hylas's that he did recently. I think that Frers has always been a designer who can produce performance oriented designs that are also more wholesome than most. I have been a fan of his since right after his S&S days. I am not familiar with Nestor Volker.
|05-16-2008 08:20 AM|
|copacabana||JeffH, what do you think of the Argentine designers German Frers and Nestor Volker? They are very popular here.|
|05-16-2008 03:17 AM|
|bestfriend||Thanks JeffH. More than enough to get me started. Don't start arguing on my account fellas. I just wanted something very general. I'll fill in the blanks later myself.|
|05-16-2008 02:16 AM|
I guess this is a situation where what was once considered to mean one thing, now means something else. The CCA's were often described as rather beamy in reviews of the day, but aren't considered to be beamy these days. I look at the Bristol 34 and do not consider the sailplan to be a high aspect ratio when looking at what is considered high aspect today. BTW, the Bristol 34 ('71-'78) is a revision of the Bristol 33, first produced in 1968, and is not a true CCA design. While it has overhangs, they are not the typical CCA 30%. This directly contradicts the short waterline rule CCA is so well known for. The 33/34 is marginally wider than comparable length true CCA designs. It may have been raced under CCA rules, but it was in no way an optimal, as you say, "rule beater." It actually favored Herreshoff's SORC 41 design. As for the Tartan, what's this A and B business? I'm aware of the 34C, referring to design #1904, which had 3 boom designs. The 12 footer, of which an actual production model is in question, the 14 footer would've been for CCA, the 10.5 footer for IOR. The boom was shortened to gain a better rating under the IOR. CCA rating guidelines favored low aspect rigs. The Tartan 34C may have been a CCA era hull, but it didn't fit the CCA ratings rule, at least with regard to the short boom rig. It was a CCA design fitted with a high aspect ratio rig. So was it a true CCA boat under the rules? No. Your statement that CCA boats had high aspect rigs is misleading because it reads like the CCA made a radical rule change when it was actually replaced with the IOR, and the higher aspect rigs came about to gain better IOR ratings. CCA ended around 1970, but the 34C was produced til 1978. How can that be CCA-era production if the CCA era had ended 8 years earlier? Also, with regards to "with the shortest foot of all at the end of the very CCA era," the short boom was introduced in 1973, well after the CCA was officially superseded by the IOR,
On a side note, it's interesting that the Tartan 34C had a dramatically shortened boom to fit the IOR racing rule. Racing. Speed is everything. When I asked the Sailnet board and other individuals not on Sailnet about doing this very same thing to reduce weather helm, all I got was, "Don't do that, you'll lose power." I barely had a clue at the time and it seemed like a good idea to me, and here Tartan was, doing the very same thing.....for racing.
"However, this progressive foreshortening of the boom was done primarily to provide for a better IOR rating. An added or side benefit was a significant reduction of the rather heavy weather helm experienced while on a reach in heavy going."
I guess the lost sail area, along the leach, not along the chord where the power is, isn't such a bad deal after all.
The C&C 39? Gimme a break. That's one of the first boats ('72-'74) actually designed to meet the IOR rule, early IOR at that.
The Hinckley 38 doesn't appear to have much in the way of high aspect either. It was, however, S&S's first cored hull. Now there's a claim to fame.
|This thread has more than 10 replies. Click here to review the whole thread.|