How do you feel about plumb bows on cruisers?

[PerfectPirate]

By all means, let us look at those Cornish Crabbers and Bristol Channel cutters. Sure, they have plumb bows. But they also have very broad, rounded bows, not those sexy, narrow racing-style bows that distinguish the current European production boats. If you look at the deck plans for those Cornish Crabbers, et al., they achieve close to maximum beam within the first 25% of their hull length. Full beam width occurs about 40% of the way back from the bow.


When I look at the deck plans for Beneteau and Hanse boats, I see a narrow, tapered bow extending far back and not achieving maximum beam until you are 60 to 65% of the way back from the bow. Near-maximum beam is then carried all way back to the stern, so that you can have a cockpit suitable for square-dancing.


This topic line has focused solely on the vertical orientation of the leading edge, with no discussion about the impact of flaring out the hull above the waterline, with consequent increase in hull volume and redirection of water out to the sides. All of the modern European productions boats which I have seen have topsides that go virtually straight up, with almost no sideways flare until you get nearly back to the point of maximum beam. So, my expectation is that those fine, narrow bows will plunge deeper into waves and not succeed in redirecting the spray outwards and away from the deck. This is why we see so many dramatic pictures of modern racing boats doing a submarine impression. The Bristol Channel Cutters have huge amounts of volume in their bows, and flare close above the waterline, so they will not plunge deep despite having a plumb bow. Most classic cruising yachts (of the fiberglass era) which have overhangs also feature a significant amount of flaring outwards on the bow above the waterline. This also provides much more habitable interior space in the bow area.


As for reverse bows, there is a reason why so many large commercial and military ships have the "Maltese" style bow, with a bulbous projection just below the waterline. Not only does it provide reserve buoyancy, it also functions to help break the surface tension of the water, making it more efficient for the ship to cleave through, thereby saving fuel. At least, that's how Jacques-Yves Cousteau explained it. But they still have overhangs and flared bows above that Maltese bulb.

[malbert73]

I think they look cool and certainly in theory are faster for LOA given extended waterline.

But then again LOA on nearly every new plumb bow cruiser seems to be extended by 3 feet for a permanent anchor sprit so maybe it’s the same speed per LOA and you lose usable LOA to a sprit

[rslifkin]

Originally Posted by malbert73

I think they look cool and certainly in theory are faster for LOA given extended waterline.

But then again LOA on nearly every new plumb bow cruiser seems to be extended by 3 feet for a permanent anchor sprit so maybe it’s the same speed per LOA and you lose usable LOA to a sprit

That only matters if LOA is really LOA. Typically the published LOA excludes bolt on parts like a gigantic anchor roller. So they get to claim the smaller size and it only becomes an issue if a marina decides to get out the tape measure.

[Searles]

Big problem with anchor and chain ripping the stem and fwd sides when retrieving in any sort of sea ,an unbalanced hull at any angle of heel ,must be sailed flat .⛵️⚓️

[nortonscove]

Not sure the market hasn't answered this one. If you are the outlier you must ask why. My brief experience with a full keel was that it too can be very wet as all that weight doesn't really wish to lift over oncoming seas. And I wasn't in any sort of heavy weather. There's something to be said for reserve buoyancy.

The other issues included the miniscule cockpit that offered no protection and tiny drains that offered little assurance. I'll take my mid nineties Beneteau any day thank you.

[DMF Sailing]

Originally Posted by nortonscove

Not sure the market hasn't answered this one. If you are the outlier you must ask why. My brief experience with a full keel was that it too can be very wet as all that weight doesn't really wish to lift over oncoming seas. And I wasn't in any sort of heavy weather. There's something to be said for reserve buoyancy.

The other issues included the miniscule cockpit that offered no protection and tiny drains that offered little assurance. I'll take my mid nineties Beneteau any day thank you.

The market has decided that people want boats that are fun to entertain on, fun to sail in fair coastal conditions, and comfy to live on. And I'm right there with them.

It's also, I think, why makers of more traditionally designed sailing craft market their new models as being fun to entertain on [looksie! 8 people in the cockpit of a 35-foot 'bluewater' boat! And they're smiling! (Other than the guy who looks like my dad, who never smiled on a boat] and looking like Ikea below.

Boatman, you deliver all kinds of yachts, it seems. Does your average modern cruiser perform the same as a craft such as the one pictured below when it gets rough in the Gulf of Lions?

[Not that I'm headed there any time soon.]

[Clivevon]

"By all means, let us look at those Cornish Crabbers and Bristol Channel cutters. Sure, they have plumb bows. But they also have very broad, rounded bows, not those sexy, narrow racing-style bows that distinguish the current European production boats. If you look at the deck plans for those Cornish Crabbers, et al., they achieve close to maximum beam within the first 25% of their hull length. Full beam width occurs about 40% of the way back from the bow."
You are right, of course. I think it was called a codfish bow - not sure why unless that design was copied from fishing boats of the era.

[ohthetrees]

Most that needs to be said has been by now. But I own a Hanse 505, exactly the design style you are taking about, and have sailed Hawaii—>Seattle—>Mexico in the last year, so I’m pretty familiar with the handling characteristics of this plum/wide design philosophy.

In all, I think the pros out-weigh the cons. The plum bow, does allow water over the foredeck in moderate conditions, that an old-school design might deflect. Not much to the cockpit though. Maybe because mine is relatively long with a lot of freeboard? Plum bow is more comfortable in these conditions, in my opinion, the bow does a great job of piercing through waves. Flairs/overhung bows increase buoyancy as they bury, leading to a quick upward motion. From that point of view my boat is more comfortable than older boats I’ve sailed. By the time conditions are rough, things have equalized, all sailboats get wet in harsh weather.

There can be slamming because of jumping off waves onto the flat bow section, but that is also because my boat can still go quickly upwind in those conditions. I slow to 6kn, and all is comfy again.

I really like and prefer the modern hull shape. The only point of sail I don’t think is superior is down wind in heavy seas. The wide stern gets picked up by a corner, and the deep keel feels like a potential tripping hazard. My boat has a powerful rudder, so I’ve never rounded up, but when seas are unpleasant, going downhill, I’m trying to slow the boat down if I go faster than 9kn. Flat seas are another matter! No speed limit!

[DMF Sailing]

Originally Posted by ohthetrees

Most that needs to be said has been by now. But I own a Hanse 505, exactly the design style you are taking about, and have sailed Hawaii—>Seattle—>Mexico in the last year, so I’m pretty familiar with the handling characteristics of this plum/wide design philosophy.

In all, I think the pros out-weigh the cons. The plum bow, does allow water over the foredeck in moderate conditions, that an old-school design might deflect. Not much to the cockpit though. Maybe because mine is relatively long with a lot of freeboard? Plum bow is more comfortable in these conditions, in my opinion, the bow does a great job of piercing through waves. Flairs/overhung bows increase buoyancy as they bury, leading to a quick upward motion. From that point of view my boat is more comfortable than older boats I’ve sailed. By the time conditions are rough, things have equalized, all sailboats get wet in harsh weather.

There can be slamming because of jumping off waves onto the flat bow section, but that is also because my boat can still go quickly upwind in those conditions. I slow to 6kn, and all is comfy again.

I really like and prefer the modern hull shape. The only point of sail I don’t think is superior is down wind in heavy seas. The wide stern gets picked up by a corner, and the deep keel feels like a potential tripping hazard. My boat has a powerful rudder, so I’ve never rounded up, but when seas are unpleasant, going downhill, I’m trying to slow the boat down if I go faster than 9kn. Flat seas are another matter! No speed limit!

Ah, Othetrees, I've been waiting for you. In a Hanse 415 and decent following seas, I've had trouble controlling the boat (in my avatar, Kira is caught off guard by a rather smallish 8-foot aberration to the 4-6' wind waves that particular day.)

I'm so curious about you 'slowing down'...so you're saying that, say, in 20-25 knots true, as we were that day, with one reef and skating along at 8-9 knots, you'd... toss in another reef to slow down and make the ride easier to control?

Upwind slowing down I get, but this is a new one to this slow-down-the-boat newbie....

[rslifkin]

Thinking with a powerboat mindset, slowing down upwind to avoid pounding makes perfect sense. But I don't understand the need to slow down when going downwind.



Generally, with a wide, flat stern, you'd want to go faster downwind provided you can avoid digging the bow in and bow steering (which isn't much of an issue with the very shallow forefoot of a modern sailboat). The fast you go, the less the waves are overtaking you, so the less they push you around. And the faster you go, the more water you have over the rudders, so the more rudder authority you have to keep things in line.

[boatman61]

Originally Posted by DMF Sailing

The market has decided that people want boats that are fun to entertain on, fun to sail in fair coastal conditions, and comfy to live on. And I'm right there with them.

It's also, I think, why makers of more traditionally designed sailing craft market their new models as being fun to entertain on [looksie! 8 people in the cockpit of a 35-foot 'bluewater' boat! And they're smiling! (Other than the guy who looks like my dad, who never smiled on a boat] and looking like Ikea below.

Boatman, you deliver all kinds of yachts, it seems. Does your average modern cruiser perform the same as a craft such as the one pictured below when it gets rough in the Gulf of Lions?

[Not that I'm headed there any time soon.]

Most of my deliveries have been Cats or modern fin keeled boats though I did do a 65ft bilge keeler across the Atlantic.
I have also owned both the modern fin Bene, the long fin narrow Westerly and the full keel type..
Bene's are less comfortable to windward and the wettest in a sea, the long fin was more comfortable close winded and the last type I rode backwards across the Biscay one December in 11metre seas and 60kt+ winds with fully reefed main only for 12 days till I reached N Spain.. never felt in danger once.. Wet.?? Definitely..

PS; the seas and wind speeds were not my estimate but Spanish Meteo quotes.

[Dockhead]

Originally Posted by malbert73

. . . But then again LOA on nearly every new plumb bow cruiser seems to be extended by 3 feet for a permanent anchor sprit so maybe it’s the same speed per LOA and you lose usable LOA to a sprit

Exactly. One way or another, you need to extend the deck to some point forward of the forward-most point of the waterline. You might as well have some fiberglass out there, gaining a lot of buoyancy (making the boat drier).

Not just for anchor-handling, but for the headstay or at least an anchor point for a downwind sail.

So I really don't see any point of plumb bows unless you don't WANT the added buoyancy, which does make the boat pitch more. But where I sail, I DO want the added buoyancy and don't mind a bit of added pitching.

Yet another advantage of an at least slightly raked bow is in a collision. I hit an uncharted rock on my boat in Finnish waters which was slightly below the surface. Because of the rake of my bow, I just rode right up on the rock without any damage at all. But if my bow had been plumb?

[Dockhead]

Originally Posted by rslifkin

Thinking with a powerboat mindset, slowing down upwind to avoid pounding makes perfect sense. But I don't understand the need to slow down when going downwind.

Generally, with a wide, flat stern, you'd want to go faster downwind provided you can avoid digging the bow in and bow steering (which isn't much of an issue with the very shallow forefoot of a modern sailboat). The fast you go, the less the waves are overtaking you, so the less they push you around. And the faster you go, the more water you have over the rudders, so the more rudder authority you have to keep things in line.

In big sea conditions you want to avoid overspeeding out of control down the wave faces. So faster is not always better downwind.

[rslifkin]

Originally Posted by Dockhead

In big sea conditions you want to avoid overspeeding out of control down the wave faces. So faster is not always better downwind.

The question becomes what factors cause the boat to become hard to control when surfing quickly? If it's got enough rudder, preferably a balanced spade rudder with clean water flow to it (to avoid losing rudder authority from turbulence or the rudder forces becoming excessive), the bow isn't digging in, and the hull is flat enough to plane, it should be possible to surf at a fairly high speed without control issues. Just requires good attention from the person at the helm or a good autopilot and a gentle touch on the steering, as it'll be pretty sensitive at high speed.

[ohthetrees]

Originally Posted by DMF Sailing

Ah, Othetrees, I've been waiting for you. In a Hanse 415 and decent following seas, I've had trouble controlling the boat (in my avatar, Kira is caught off guard by a rather smallish 8-foot aberration to the 4-6' wind waves that particular day.)

I'm so curious about you 'slowing down'...so you're saying that, say, in 20-25 knots true, as we were that day, with one reef and skating along at 8-9 knots, you'd... toss in another reef to slow down and make the ride easier to control?

Upwind slowing down I get, but this is a new one to this slow-down-the-boat newbie....

Exactly right. When big, or even just lumpy seas are lifting my stern and causing me or the autopilot to use a lot of steering input, I try to keep max speed around 9 kn. So far I have always been able to progressively reef, but I have a drogue and 300’ of stout line to slow me further if necessary. I find at <9kn with the powerful rudder I always have plenty of steering control and don’t feel in danger of tripping over the keel. But it does take active steering and/or a good (and well tuned!) autopilot in those conditions.

Originally Posted by rslifkin

Thinking with a powerboat mindset, slowing down upwind to avoid pounding makes perfect sense. But I don't understand the need to slow down when going downwind.



Generally, with a wide, flat stern, you'd want to go faster downwind provided you can avoid digging the bow in and bow steering (which isn't much of an issue with the very shallow forefoot of a modern sailboat). The fast you go, the less the waves are overtaking you, so the less they push you around. And the faster you go, the more water you have over the rudders, so the more rudder authority you have to keep things in line.

In big seas, and strong winds, if I didn’t slow the boat, I’d be planing, and going god know how fast down the waves. 20kn? I’d be terrified of tripping over the fin keel. Some people do advocate for the “go fast” approach, but I think it would take an expert helms-person using their full attention to carry it off. That is tough on a 2 week passage. I prefer to keep it in the realm the autopilot can handle.

The fin keel brings lots of performance advantages, and again has more pros than cons. But a con is that the boat wants to turn, which is only held in check by a large powerful rudder (my rudder blade is 8’). When going fast down waves, I can feel the boat wanting to turn, and so far, I’ve kept it at speeds the rudder can cope. I feel it is increasingly likely the faster I go that I turn uncontrollably and trip on the keel in big following seas. I want to avoid that. So far keeping it <9kn has kept it manageable and comfortable. There is some safety margin there, I could probably go faster safely, but I’m a cruiser, not a racer, I’ve got kids aboard, bla bla bla.