Bow shape and characteristics under sail: Overhang v straight stemmed

[silver-fox]

You could have drawn up a similar list of undesirable characteristics when Angus Primrose introduced the Moody 33 and 36 onto the scene in the mid 70's. It would have been drawn up by people who had been brought up in deep long keels, small cockpits, gaff and ketch rigs, transom hung rudders and so on. Indeed the list would have featured in all the reviews of the boat at the time.

However it set the scene for a style of boat that dominated the market for the next 30 years or so, reflecting the fact that it suited the main market, that is North European coastal waters sailing, very well. Buyers wanted boats that could stand up well in cold wet environments and had plenty of warm below decks space. Such characteristics also turned out to suit liveaboards when that became popular - even though there were significant shortcomings when used in warmer climates. No different really from the previous generation that used workboat derived hull forms for the same purpose - because they were available.

Things have moved on, though and now the main market for cruisers is warm water orientated, particularly the Med, so unsurprisingly builders tend to design boats suited to that environment because that is what buyers want. But just as in previous generations such boats get used in other ways - look at the ARC entries to see what I mean.

The thing about ultimate stability is in practice overrated in my view. The number of times a boat gets into a situation where this is an issue is tiny. Most boats are used well within their capability and owners will chicken out long before capsizing becomes an issue. More important is being able to sail the boat comfortably within its capability and modern designs with easy handling are just as good in this respect as older boats.

In 20 or 30 years time, cruisers of all sorts will be happily buying today's style of boat when the price comes down to affordable levels and probably moaning about the unsuitability of what will then be "modern" boats - but actually a bit like today it might reflect the unaffordability of such boats as much as their unsuitability.

Funnily enough having been brought up on "traditional" boats - in my case a heavy long keeler, I had the same view about modern boats until I could afford to buy a new one and then realised what I was missing!

Tranona, In suggesting "You could have drawn up a similar list of undesirable characteristics........." you are implying I am critical of modern boats, I haven't expressed a view on modern boats! Neither was my list of characteristics described as "undesirable" In fact I was careful to state "

Boat design is evolving, stimulated by new materials and new ideas. I am just trying to learn more from a designer what the effect (or cost if you like) of each of these design decisions really is.

 

[Tranona]

Tranona, In suggesting "You could have drawn up a similar list of undesirable characteristics........." you are implying I am critical of modern boats, I haven't expressed a view on modern boats! Neither was my list of characteristics described as "undesirable" In fact I was careful to state "

Boat design is evolving, stimulated by new materials and new ideas. I am just trying to learn more from a designer what the effect (or cost if you like) of each of these design decisions really is.

So, not sure why you are listing those particular characteristics rather than others. Is it because those are the ones that are different from older style boats? You have also sort of stated the obvious in that they reflect the market they are aimed at.

Many of the features are interlinked. If you carry the beam aft you can have aft cabins and a big cockpit. Wide stern allows a big bathing platform but access is limited by a big wheel, so why not have 2 wheels.

As always it is the designers job to turn what he thinks the customer wants into a functioning package.

 

[Ludd]

As regards the "bulbous underwater bow" the only one I know of is the Elvstrom Coronet. RAI of this parish sails one.

 

[silver-fox]

So, not sure why you are listing those particular characteristics rather than others. Is it because those are the ones that are different from older style boats? You have also sort of stated the obvious in that they reflect the market they are aimed at.

Many of the features are interlinked. If you carry the beam aft you can have aft cabins and a big cockpit. Wide stern allows a big bathing platform but access is limited by a big wheel, so why not have 2 wheels.

As always it is the designers job to turn what he thinks the customer wants into a functioning package.

I have made it clear all the way through the thread I am looking for the pros AND cons. I want to become more informed.

For example on my boat I have in mast roller reefing. It is widely condemned on these fora for its (alleged) propensity for jamming and for the reduced drive because it has no roach, and that it raises the centre of gravity of the boat affecting stability. My comments after 7 years use are: -

1. It doesn't jam. In 7 years there have been a couple of times I have cocked it up and had to let a roll or two out before reefing - but that's been the sum total of problems
2. Yes it is less powerful but its ideal for a husband and wife team (or any weak crew) because you can reef from the cockpit.
3. I prefer it to slab reefing and boom roller reefing both of which I have had on previous boats

That then is my take on in mast roller reefing, I am a convert until something better comes along.

If we turn to wide beam aft where you have very succinctly summed up the benefits but have not mentioned any disadvantages. Can I ask is that because there are none? If so that is great, but begs the question why boats haven't been built like that previously, given all the advantages? After all it is considerably more expensive to build a shaped stern than a flat transom!

Finally can I say I really have no desire to pull any specific boat genre or make to pieces.

 

[BrianH]

I have made it clear all the way through the thread I am looking for the pros AND cons. I want to become more informed.

Which is exactly how I interpreted your post and applaud you for it as you have articulated my own interest but was concerned to be thought to have another agenda.

For example on my boat I have in mast roller reefing. It is widely condemned on these fora for its (alleged) propensity for jamming and for the reduced drive because it has no roach, and that it raises the centre of gravity of the boat affecting stability. My comments after 7 years use are: -
[...]
3. I prefer it to slab reefing and boom roller reefing both of which I have had on previous boats
That then is my take on in mast roller reefing, I am a convert until something better comes along.

Perhaps your boom roller reefing was the same as I had and learned to dislike intensely, which put me off in-boom roller reefing for a long time but which I now have. That is a totally different principle and I am now a convert.

Thank you for this thread and please continue to ask these interesting questions.

 

[Tranona]

I have made it clear all the way through the thread I am looking for the pros AND cons. I want to become more informed.

Sorry if I misunderstood, but the characteristics you listed were mostly the ones people list when they are criticising modern boats - perhaps because the pros are not ones that meet their perceived requirements.

Much of boat design is evolution and influenced by two main things - what can be built with the materials available and in the case of cruising yachts, heavily influenced by racing - particularly rating rules. So the combination of GRP construction and the IOR produce the typical cruising boat of the 1970's -90's.

Relax those influences and design boats for different purposes using different technology and you get different results. So for your example of wide sterns - the pros are obvious, the cons less so. But typically dynamic, keeping balance and structural. Solutions to these problems you can see in features like chined hulls, twin rudders and fractional rigs that don't have loaded backstays.

Think that answers your question as to why boats were not built like that in the past. Open transoms and bathing platforms are not high on the list of priorities in a boat designed for cold northern waters. Small cockpits and narrow sterns are useful when bashing to windward in the English Channel. You can find many more examples of environmental factors having influence on design. Equally advances in materials make many of the new features practical, particularly the engineering of composite structures that make things like spade rudders, deep keels, tall light rigs etc feasible.

Not all new ideas catch on, or they drift out of use. Sugar scoop sterns for example held sway for a long time because they were a cheap way of providing extra sailing length and a bathing/boarding platform. Now going out because of the desire to increase the usable accommodation length but keep the same cockpit size, and made possible by engineering reliable drop down transom platforms. So you can get almost the same accommodation in a Bavaria 33 as in my older style 37 - not surprising as the LWL of the latest 33 is actually more than the 37, which has a raked bow and a sugar scoop!

Not everybody likes new developments, but often they are not the buyers, so builders don't take too much notice, preferring to try and meet the needs of those that are buyers. No different really from any other consumer product.

 

[Marsupial]

Other what I call passive design features have come on over the years, for example a walk through transom also allows for a very quickly draining cockpit - I wish I had one of those 30 years ago! even if it rained the cockpit would fill with water and like British rail it only took 1 leaf to block the drains. Take a wave over the side and it would drain - eventually.

a few improvements I have noticed over 50 years, winches you can tail without chewing lumps out of the combing, side decks that drain, sails you can leave on the boat all year round if you must and put them away wet and they don't fall apart. Engines that work (well, most of the time), in general most of the mechanical bits have become more reliable over the years.

not sure I understand why a raked bow has more reserve buoyancy than a plumb bow as both are flared; immerse them and the plumb bow will displace more volume.

For me the major problem with a plumb bow is the anchor, how to prevent it from hitting the gell.

the modern mantra is stronger lighter and as other have said in 20/30 years we will look back at current designs and muse on how well made boat were in the old days (now). I still remember the arguments over cotton sails and how polyester sails would be stronger than the rigging and break the mast. Things move on.