Modern sailboats with wide sterns versus Narrow sterns

[ds797]

A lot of modern sailboats now have VERY wide sterns - Jeanneaus, Elans, Dehlers, Beneteaus etc.

Just wondering how this affects upwind performance in a bit of a blow?

I guess downwind performance is much improved compared to boats with narrow sterns like Contessas, Sadlers etc but what I want to know is about sailing upwind in stronger winds.

Can anyone shed any light?

I guess any boat is a compromise but what are the pros and cons of these modern designs?

Thanks.

 

[KREW2]

I find upwind performance good but, in a blow I do have to reef earlier than most otherwise it gets a bit of a handful. This does not bother me as in 24knts of wind with 2 reefs in the main and about half the genoa out I can get 6.5 to 7knts SOG with a 0.9knt following tide

 

[Phoenix of Hamble]

But I always considered the need to reef early related to high form stability, eg a flat bottom, rather than a wide stern per se (the flat bootm meaning she'll be stiff and fast until the flat bottom is too heeled, and then a lot slower and a bit more tender than a more rounded bottom).... but I guess the two are quite closely related..... without a fat stern, the bottom wouldn't be so flat...

That said, I never seem to find upwind speed a problem......

 

[Habebty]

I have a Sadler 290, v. wide stern. Two weeks ago I was getting a steady 7.5kts sometimes 8kts TTW closehauled in I think according to Harwich VTS about 18-22kts of wind. One reef in main and a bit of genoa rolled up. Pointing very well and in a good chop in the Medusa Channel.
So yes they can go well upwind especially if well ballasted and balanced. /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif
I might be a bit biased /forums/images/graemlins/wink.gifbut I can't think of too many disadvantages. Other than marinas allocating a too narrow berth on arrival for a traditionally narrow 29-0 footer /forums/images/graemlins/tongue.gif then refusing to believe the length when they see the boat!! /forums/images/graemlins/grin.gif

 

[dunedin]

One key factor is the balance of stern and rudder. Some wide sterns and shallow rudders can lose grip suddenly when the boat heels too far, and then lifts most of the rudder out.
This is a matter of some design subtlety, and some boats get it right, others don't - could cause great controversy suggesting boats which didn't quite get it right and which did

 

[Salty John]

Some modern beamy boats get their stability from beam rather than ballast ratio. This means they are fast off the wind, as you say, but tender up wind and so they heel a lot more. Thus, you have to reef early. Also, when well heeled (does that make them affluent?) these broad beam boats can lift the rudder out and lose stability - which is why some have twin rudders.

 

[moondancer]

This is a huge subject which has been debated at length here many times. Not sure I should say this here but Peter Poland in a recent Sailing Today did quite a good article on the upsides and downsides of modern hull design. An awful lot depends on what you want to use your boat for.

I think it was about 3 months ago.

 

[exfinnsailor]

Will let you know .. Got a new Beneteau 323 on order with twin rudders so if we loose one we have a spare .. What do we do if you loose both .. Hmm try to remember how to sail without one ! .. Prop wash over none existant rudder should be fun .. Wind up keel will help if we touch the bottom .. /forums/images/graemlins/tongue.gif

 

[Lizzie_B]

Don't think it's that simple. There are so many other variables, i think it comes down to individual boats. I recently sailed on an Oceanis 331 which went well to windward and handled fairly rough seas well without slamming.

Was impressed, much better than the Bav 34, which in those conditions would have been shaking us all to pieces and not made any headway.

However, it didn't come close to my Elizabethan 31 which would have probably pointed about the same, but would have given the crew a much less tiring and more comfortable ride.

My Catalina, which has a fine entry and inner sheeting tracks for windward work would have outpointed all by a considerable margin while maintaining good boat speed and also give a very comfortable ride for the crew.

Downwind, the Elizabethan was an absolute pig, but gybe tacking she could get down wind as well as the broader sterned boats going straight downwind.

The Catalina, although a 70's design with a narrow stern is excellent downwind.

I think crew comfort/ride quality is an often overlooked and important safety factor and raw 'performance' figures provided by manufacturers and 'heaven forbid' some boat reviews are not always that revealing.

I think in an ideal world you would be able to go out and try different boats in a variety of conditions and see which one best suits the type of sailing you envisage doing, but of course, very rarely is that possible which is why we have to research as much as possible before parting with our dosh.
/forums/images/graemlins/smirk.gif

 

[mortehoe]

I don\'t think that sterns have much to do with this

It's the underwater hullshape that affects performance. Bruce Farr invented the O-60 platfom planing hull which is now adopted by the go-faster boat builders.

Now, the Contessa that you are referring to has to be the CO26 which is a David Sadler rip-off of the Van de Stadt 33 but much improved with the subtle variations to the hull and skeg.

The Farr boats (ie Open 60's and all their derivitives ie Bendytoys ) are not only wet boats when going to windward but slam so much as to drive you nuts, but they sail like and are as responsive as dinghies.

If I had the monies then I would have 2 boats: 1) a long keel for winter sailing (ie Lyle Hess BCC and 2) a Bendytoy for the summer .... ie Beneteau 473 /forums/images/graemlins/smile.gif

But .........

 

[wingdiver]

Re: I don\'t think that sterns have much to do with this

There are so many other hull design factors that help or hinder.

You find a lot of the modern BavBenJen's etc have a very 'blunt' prow, a flat wide underwater profile and not that much weight.

This can lead to stalling when the bow hits a biggish wave and slamming when you bellyflop after going over a big one.

The lighter weight helps to sail in lighter winds.

A heavier boat with a long keel will power through the waves but will not get going until the wind gets over a F5 when some of the lighter brigade are starting to reef.

IMO - but then again, I am biased. /forums/images/graemlins/grin.gif

 

[Oldhand]

I think you have to consider the righting moment vectors as a hull heels to get an idea of the difference. A wide stern produces more righting moment from aft of the longitudinal centre line than a more balanced hull shape. Apart from this making the stern ride high and the bow to dip, it will cause additional turning moment to windward. To compensate for this, keels and sail plans should be further forward, which in turn needs a full hull form forward to prevent bow down trim. It is thus IMHO much more difficult to design a well balanced boat with a fat stern than with a more moderate shape and thus there is more scope for getting it wrong.

I would guess from observation that the majority of fat sterned cruising yachts have to be sailed more upright than more moderate shapes as they will build up weather helm more quickly with heel.

 

[Sybarite]

Wide boats have been associated with fast off-the-wind sailing but they are now designed to sail upwind "on their edge" which means that the effecive beam at the turn of the bilge becomes very narrow. To complement this they have twin rudders and very deep fin keel or kanting keels. They also have generally a very fine entry to reduce slamming. Great fun for racing but probably not very comfortable for cruising.

John

 

[jamesjermain]

This is a big subject but since the most important points have already been addressed I would just like to add a personal comment.

Some people seem to be saying 'have to be sailed more upright' as though sailling upright was a bad thing. I would like to turn the argument on its head and say: 'older designs have to be sailed on their ears because they lack the form stability of modern yachts. Because they also have lower sail area/displacement ratios they have to hold on to full sail longer for maximum performance which means heavier loads on winches etc. Also IOR inspired rigs mean small mains and large genoas which need powerful winches and powerful winchmen to handle them. In light to medium airs they lack the power to achieve hull speed'.

Of course, this is not the full story and there is much to be said, in cruising terms, for the heavier displacement, well-balanced hull form, with nicely vee sections forward, under an easily managed but powerful rig.

(Edit)...Or, of course, a catamaran

 

[Koeketiene]

Re: I don\'t think that sterns have much to do with this

[ QUOTE ]

A heavier boat with a long keel will power through the waves but will not get going until the wind gets over a F5 when some of the lighter brigade are starting to reef.


[/ QUOTE ]

True - for our previous boat (Etap 38i) an F5 was pretty much borderline for comfortable sailing, and even then with a reef in the main.

Now for Guapa it takes an F5 before things start to be fun. Even F6-7 she takes in her stride.
Current light airs in Normandy are costing me lots of money (diesel).
Harwich-Ramsgate-Brighton-St Valery en Caux-Dieppe -> only 7 hours of sailing, all the rest was motorsailing.

Life's a compromise.