Please explain the advantage of an overhang to a longer waterline?

[angelfish2]

Thanks everyone for such an interesting thread!

Originally Posted by valhalla360

...For many a long overhang looks right because that's what they've seen for decades. In 40yrs, our kids will see the stray old boat with 5' overhangs and it will look strange to them. It will be a slow evolution.

valhalla, (love your user name), actually I don't think so. All of us have seen (at least in pictures) the majesty and beauty of clipper ships and they have been around for quite a few years. They certainly don't look strange to me.

I guess beauty is in the eye of the beholder but for my part, a clipper bow, graceful shear, and overhung stern is a real "head-turner". They do tend to be a bit more slender, but there's no denying that they are beautiful. I think most of them have pretty good sized drafts, also.

However, as one who is in the middle of a very big vanishing project, there is usually an awfully lot of exterior teak.

[scallowayuk]

Originally Posted by Terra Nova

Overhangs increase reserve buoyancy and righting moment, also decrease wetted surface in light air.

also decrease waterline length my boat is 22ft with 22ft waterline ,she makes fast passages.

[scallowayuk]

Originally Posted by thomm225

This is that post I remembered from that other thread. The link to that thread is:

http://www.cruisersforum.com/forums/...ang-15340.html

This post was from Southern Star:


Overhang, especially at the bow, is not simply about looks. Rather, as Robert Perry pointed out (in Robert Badham and Robby Robertson, Sailor's Secrets, International Marine, Camden Maine, 1999 at p. 193:

"Some things, though, begin to look better the heavier the weather gets. Plumb stems are a modern trend. They obviously maximize waterline length, but in a cruising boat do you want to give up a foredeck and make your boat into a submarine for an extra little boost in top end speed? Traditional elements like overhang are traditional because they work. Overhang keeps people dry and provides space to do what foredeck work you have to do."

To his I would add the importance of front overhand in anchoring - have any of you tried to retrieve an anchor in a boat with a plum bow? It is virtually impossible, in most conditions, to avoid banging the anchor into the topsides - even with an anchor roller that extends a short distance past the bow.

The same can also be said about the current trend towards wide transoms and relatively flat underbody shapes. Yes, the flatter hull form can increase speed potential in relatively flat water, but it does so at the expense of a sea-kindly motion: the boat will tend to slam when sailing to windward.

Further, boats with such an underbody design have significantly greater inverse stability - VERY bad in a monohull. Consider the recommendations concerning seaworthiness made in the aftermath of the Fastnet disaster. Witness also various of the original Open 60's that, when capsized, stayed inverted. As you may recall, this forced a rule change that led to canting keels.

Finally, this 'modern' hull form, while having increased initial form stability, also has a tendancy to increase weather helm under heeling once the rather sharp turn of the bilge is sufficiently submerged on the leeward side.

In the result, it is often the purchasers of these more 'modern' hull forms who are slaves to fashion: they want a boat that looks like a modern racing boat; they want the increased interior volume that is created below (they want huge aft doubles and could care less about proper sea berths); they want the home-like look of a wide cabin sole. For this they are prepared to sacrifice a degree (and sometimes a significant degree) of seaworthiness and actual sailing comfort and praciticality.

Brad

falmouth workboats ichen ferries, bristol channel pilot cutters . falmouth quay punts all have plumb bows and are fast and dry.

[jewt]

Long overhangs not only look beautiful but under sail and the boat heels they increase the effective waterline thus increasing the "hull speed' capability of the vessel.

My 69 Morgan 41 was 41feet on deck with a 30 foot water line; not very fast under power but a super sea boat when heeled, and the C/B really aided trim.

jewt
S/V Bifrost (now a Morgan 44CC)

[john61ct]

Yes but other designs with the same LOA but less overhang will be faster without the heeling, and have more space and carrying capacity for cruising.

afaict the long overhangs are artifacts of arbitrary racing design rules, no other function.

But they do look pretty grant you that.

[thomm225]

The old boat look of the long overhand is what draws many of us, but I like mine more now that I've owned a boat with one.

When I pull up my anchor, it has a bit of room to swing around without slamming into the boat.

Also, when the boat is being over taken by steep seas, I'm thinking the overhang gives my boat a drier ride by allowing it to rise up before the wave crashed into the actual stern.

[roland stockham]

Originally Posted by john61ct

Yes but other designs with the same LOA but less overhang will be faster without the heeling, and have more space and carrying capacity for cruising.

afaict the long overhangs are artifacts of arbitrary racing design rules, no other function.

But they do look pretty grant you that.

This misses the point. The size of the boat depends on WLL and displacement. A boat weighing 10,000lb on a WLL of 24ft will be faster in some conditions and sail better with only a minimal weight penalty if she has reasonable overhangs. Yes of course if you add 4ft to the WLL she will be faster because she is now a 28 footer. The whole point with overhangs, bowsprits etc is to add deck length and change her behavior at sea for the same size boat. The down size is that marinas charge by LOA not the size of the boat so your little 5T classics pays the same as a 35ft houseboat but they sure don't sail the same.

[john61ct]

I use LOA as **my** canonical measure of a boat's length.

Within that context, afaik, I see a lesser overhang as all good, except for looks.

I think arguing about the first statement is useless.

But I'd be very happy to learn how I'm significantly wrong wrt the second.

And I do happen to think that looks are pretty darn important.

[Elie]

Originally Posted by scallowayuk

falmouth workboats ichen ferries, bristol channel pilot cutters . falmouth quay punts all have plumb bows and are fast and dry.

Many thing to talk about.
I agree that overhangs to a point improve sea motion in a seaway, and plumb bows may at times slam to weather in heavy winds.
But in reality, most of sailing yachts design had been is largely influenced by sailing handicap rules. CCA boats used long overhang with the idea to increase its real measured(an important handicap) waterline length. So did the IOR rule with added bonus of very wide middle section and low ballast very high placed. The production boats tryed to look up to date and current with the look a a good racer.
French designers of purely cruising yachts started to get rid of all these idiot handicap rules along with other like Perry, Farr, and many others. Wide sterns and flatish sterns when well blended(Unlike IOR boats) do a good job upwind with good form stability because the hull form with good volume forward, and relatively average overhangs forward. By boat is a Joubert Nivelt design and I'm alway happily surprise by its good behavior in heavy seas and wind. I think that boat form design is influenced by many parametters and good architects with the proper computer tools are capable of designing very modern, fast and safe boat.

[scallowayuk]

Originally Posted by Elie

Many thing to talk about.
I agree that overhangs to a point improve sea motion in a seaway, and plumb bows may at times slam to weather in heavy winds.
But in reality, most of sailing yachts design had been is largely influenced by sailing handicap rules. CCA boats used long overhang with the idea to increase its real measured(an important handicap) waterline length. So did the IOR rule with added bonus of very wide middle section and low ballast very high placed. The production boats tryed to look up to date and current with the look a a good racer.
French designers of purely cruising yachts started to get rid of all these idiot handicap rules along with other like Perry, Farr, and many others. Wide sterns and flatish sterns when well blended(Unlike IOR boats) do a good job upwind with good form stability because the hull form with good volume forward, and relatively average overhangs forward. By boat is a Joubert Nivelt design and I'm alway happily surprise by its good behavior in heavy seas and wind. I think that boat form design is influenced by many parametters and good architects with the proper computer tools are capable of designing very modern, fast and safe boat.

i think you misunderstood, i have a falmouth workboat 22ft loa 22ft waterline 3.5 tons . ive crossed the atlantic in her 4 times, she dosnt slam she has a very comfortable motion and makes good average speeds. but with these type of boats its more important to keep weight out of the bow, ,my friends wing 25 slams to windward with 25ft loa 19ft waterline, and is slow in light airs. ive read that clipper bows only work on boats over about 35ft probably overhangs work in larger boats the j class certainly go. the waterline is important in light airs displacement not so much as you can carry more sail lin and larry pardys lyle hess design tallasin goes well with a plum bow.