Plumb vertical bow

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Channel Sailor

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When I chose my current yacht one of my requirements was not to have a straight up from the water line stem. My reasons being sensible anchor handling, some degree of clearance for a mooring buoy and increasing reserve buoyancy in a chop.

So I am wondering what the advantages of a plumb vertical stem? Maybe there are be some advantages that I am not aware of. Does the small increased water line length actually make that much of a difference, is there more interior space of significance maybe.

I suspect when I come to replace my yacht with another 2nd hand slightly newer one that my choices will be increasingly limited.
 
I personally do not like vertical stems either, from an aesthetic point of view. However I really hate a forward-sloping transom and can see no practical or design reason for them on a cruising boat. There is a safety issue here. When going down the ladder on a conventional transom, the dinghy is nearer or even under you. On a forward slope, the dinghy is behind you and you are leaning the wrong way.
 
Channel Sailor said:
When I chose my current yacht one of my requirements was not to have a straight up from the water line stem. My reasons being sensible anchor handling, some degree of clearance for a mooring buoy and increasing reserve buoyancy in a chop.

So I am wondering what the advantages of a plumb vertical stem? Maybe there are be some advantages that I am not aware of. Does the small increased water line length actually make that much of a difference, is there more interior space of significance maybe.

I suspect when I come to replace my yacht with another 2nd hand slightly newer one that my choices will be increasingly limited.
Click to expand...

On my vertical stem cat the buoyancy chambers are in the lower part of the bow underneath the bunk of the front single cabin and do not intrude into the storage space under the second double berth cabin.

A raked stem would mean less storage space or a much smaller buoyancy chamber.

Richard
 
It's always a compromise.
LOA v LWL
Reserve buoyancy v load change (structural design)
Deck area
Anchor clearance
Internal volume for stowage
Looks

The old pilot cutters had plumb bows. They were considered the fastest design of their age as their job was to get the pilot out to the incoming vessel first. It also used least material in the build and was therefore most cost effective.

Ocean liners are mostly raked or clipper bowed. Keeps the water off the deck in a heavy sea.

For yachts built to a rule it will depend on the rule. LOA = Plumb. LWL= rake.
Also the profile of the bow above the water line can be a function of the fore foot construction and amount of rocker.

I would go with whatever takes your eye unless you have a specific constraint.
 
Bodach na mara said:
I personally do not like vertical stems either, from an aesthetic point of view. However I really hate a forward-sloping transom and can see no practical or design reason for them on a cruising boat. There is a safety issue here. When going down the ladder on a conventional transom, the dinghy is nearer or even under you. On a forward slope, the dinghy is behind you and you are leaning the wrong way.
Click to expand...

I have a slightly forward leaning transom (Feeling 920)

However I have a cut-out and special moulding which renders the centre part of the transom vertical as well as providing a small bathing platform.

For me it's a good compromise and I like the looks.
 
Channel Sailor said:
When I chose my current yacht one of my requirements was not to have a straight up from the water line stem. My reasons being sensible anchor handling, some degree of clearance for a mooring buoy and increasing reserve buoyancy in a chop.

So I am wondering what the advantages of a plumb vertical stem? Maybe there are be some advantages that I am not aware of. Does the small increased water line length actually make that much of a difference, is there more interior space of significance maybe.

I suspect when I come to replace my yacht with another 2nd hand slightly newer one that my choices will be increasingly limited.
Click to expand...

My last two boats have the same LW, but the new one is 4' shorter overall - 33 instead of over 37. The advantage of the new is much easier to get into my restricted berth and of course lower fees. Accommodation space very similar although different layout and allocation of space.

Don't see any difference in anchor handling as the new has a longer stemhead fitting. Anchor locker is a bit smaller and does not have space for my preferred Lofrans windlass. The deeper forefoot allows for more effective installation of a bow thruster if you want one. At the other end of the boat the loss is the sugar scoop and open transom, but the new has a much bigger drop down transom. Sterns tend to be wider as well so more room in the cockpit, although mine is a single wheel version so does not maximise space, but is ergonomically good for single handing.

Overall the displacement and sail area are the same, but the new one sails much better. This is not necessarily because of the shorter ends as the hull and keel design are different as is the rig. while "ends" make it easier to draw a balanced profile, I find the cleaner looks of some of the latest boats more satisfying to look at - but not all. The first iteration of the one I have was awful, but a new more balanced deck changed it dramatically.
 
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Channel Sailor said:
When I chose my current yacht one of my requirements was not to have a straight up from the water line stem. My reasons being sensible anchor handling, some degree of clearance for a mooring buoy and increasing reserve buoyancy in a chop.

So I am wondering what the advantages of a plumb vertical stem? Maybe there are be some advantages that I am not aware of. Does the small increased water line length actually make that much of a difference, is there more interior space of significance maybe.

I suspect when I come to replace my yacht with another 2nd hand slightly newer one that my choices will be increasingly limited.
Click to expand...


A good deal of it is fashion, as in ladies hemlines.

I like this readable overview:

http://gtyachts.com/files/PlumbStem_FashionOrPhysics_Jan2013.pdf
 
My HR34 has a sloped stern, but it is nowhere near as sloped as it appears because the styling involves a wrap around the sides. As far as I am concerned, it is more comfortable to stand on the small plaform to board a dinghy than it was on my vertically-transomed Sadler 29, even though this had a non-standard and substantial ladder.

Much depends on whether your marina measures the mini-bowsprit on plumb-stemmed boats when deciding what bow to have.
 
doug748 said:
A good deal of it is fashion, as in ladies hemlines.
Click to expand...

Quite probably. Though if you look back at what working sailing boats had for efficiency (build, load and performance) they tended to have plumb bows ... often with a pole in front to attach a sail to. Most of the boats of the early yachting pioneers were based on this "traditional" shape.

The long overhanging bows in yachts was a fashion, driven initially by rating rules which focussed on LWL measurement, and long overhangs gave "free" length when underway.
So arguably a Westerly from the 70s with a sloping bows could be the "fashion victim", and the J120 with plumb bows plus bowsprit is the "traditional" one.

Either way,, a near plumb bow (perhaps 6 inches overhang) seems optimum to me. Fast, roomy and practical.
Beauty is in the eye of the beholder (and generally based on what they were familiar with when growing up!)
 
Our Finngulf 33 was fairly straight up at the front and slopy at the back, it was at least as fast as the Sigma 38 it replaced, which was not surprising as the LWL and air draught were much the same. The wife was not impressed as I had told her we were downsizing.
But I do agree that you had to exercise a fair bit of care when recovering the anchor, I applied a couple of strips of white duck tape every spring as insurance. A 'banana' swivel which orients the anchor as it approaches the bow is a help as well.
 
A boat or Yacht should be an object of beauty, flat up and down at the front and flat up and down at the back with maximum volume down stairs may be some peoples idea of beauty; however I prefer a bit of shape at the front and also the rear to have a pleasant shape, volume down stairs is low on my list, prefer a nice tight accommodation.
Simon
 
The plumb vertical bow is simply a fashion statement in modern cheap plastic boats. Trying to make them look like racing yachts. A bit similar to the fashion for silly wide tyres on cars.
 
Malo37 said:
The plumb vertical bow is simply a fashion statement in modern cheap plastic boats. Trying to make them look like racing yachts. A bit similar to the fashion for silly wide tyres on cars.
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Funny how it has spread (just like other "fashions") across the price/size/quality spectrum. Look at the latest HRs for example.

There are clear advantages, not least greater speed potential and greater accommodation for a given amount of berth space. Just the same as when it was in fashion for boats like fishing bawleys in the 19th century and copied by yachts until the rating rules changed and created a new fashion of spoon bows and long overhangs either end.

What goes round, come round.
 
I watched a documentary a few years ago explaining that a plum bow on a fishing boat was more efficient in making progress as it would cut through the water rather than get knocked back with a sloping bow! I just wouldn,t want to be on deck when it goes through a wave :eek:
 
gertha said:
A boat or Yacht should be an object of beauty, flat up and down at the front and flat up and down at the back with maximum volume down stairs may be some peoples idea of beauty; however I prefer a bit of shape at the front and also the rear to have a pleasant shape, volume down stairs is low on my list, prefer a nice tight accommodation.
Simon
Click to expand...

It would be interesting to see how you describe your preferred girlfriend :ambivalence:
 
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