Plumb Crazy

[Alaskan Sea-Duction]

This article is from Power & Motoryacht.

would have to agree with Mr Prince. Never did like these funny looking bows.

What say you?

https://www.powerandmotoryacht.com/column/inside-angle-plumb-crazy

 

[AlaskaProf]

This article is from Power & Motoryacht.

What say you?

 

[Comodave]

Agree 100% with the author. Besides looking bad they don’t handle waves well. Watch some Haulover Inlet videos and see how they perform. Very wet boats. I think that most people that are buying them because they think they look good, they don’t, and are likely inexperienced boaters. But in Miami it is all about the looks…

 

[BroadCove]

I say...it's a boat, there is no single "correct" hull form. (Not saying you're suggesting there is one!) I can appreciate the design aesthetic, and, in a hull speed vessel, it may work. But I'm a moderate person by nature. I don't like extreme Carolina flare any more than I do a plumb bow simply for the aesthetic. If it has a functional purpose, I'm intrigued. I previously owned a Halvorsen "Gourmet Cruiser" which had a fairly plumb bow, with a bit of flare. The advantage was a 36' overall boat with a queen berth and separate head / shower. The disadvantage was it was slow and wet. It was pretty to my eye, which matters too (to me). I liked the tradeoff at the time.

 

[PM]

I kind of like the look on larger sailboats but I think it may be a fad.

pete

 

[boomerang]

The only plumb-bow boat I ever owned was a 44' Chesapeake bay deadrise, the lower bay built deadrise with a hull design having nothing but sharp angles as opposed to those built in Maryland that had softer shaped hull. My boat was as very stout ,tough as nails and gave an excellent ride but in high seas, she definitely required the high combing boards to keep the water on the outside of the boat. I prefer my bow to rise up over the seas, not go through them. I personally don't care for the looks of a bow with no rake, either. Though I think I'd rather have a boat with the vertical bow and lots of angles rather than a modern "bubble boat", as the late Tom Fexas called them.

 

[sean9c]

On these boats with plumb bows the thing that gets me is they then have a big ugly anchor roller sticking out so they can lower the anchor without it banging the bow. Just put some rake in then you won't need the big ugly roller.
Isn't there someone on this forum that had a custom plumb bowed boat designed and then has an extending, presumably hydraulic, bow roller to get the anchor far enough out to not hit the hull?

 

[CaptTom]

Kudos to the author for saying it so much better than I could have. Unfortunately that article has reinforced my dislike for that style, so I'm probably going to be even more insufferable around them. Seems a new one shows up at our marina every year.

 

[Delta Riverat]

Yeah, Pardo's...

 

[psneeld]

Wikipoedia....

"A wave-piercing boat hull has a very fine bow, with reduced buoyancy in the forward portions. When a wave is encountered, the lack of buoyancy means the hull pierces through the water rather than riding over the top, resulting in a smoother ride than traditional designs, and in diminished mechanical stress on the vessel. It also reduces a boat's wave-making resistance.

Design theory calls for very long thin hulls, so in practice most are multi-hulls such as catamarans and trimarans.

The main current usage areas are passenger ferries[1] and naval ships.[2]"

Vessels that are usually out there when ohers don't have to be.

 

[Mako]

On these boats with plumb bows the thing that gets me is they then have a big ugly anchor roller sticking out so they can lower the anchor without it banging the bow. Just put some rake in then you won't need the big ugly roller.
Isn't there someone on this forum that had a custom plumb bowed boat designed and then has an extending, presumably hydraulic, bow roller to get the anchor far enough out to not hit the hull?

Agree that I dislike the ramming rods, but the proposal you mention is an overkill. Easy solution is just to employ a stockless anchor. Nowadays they are available in HHP and SHHP versions as well.

 

[rslifkin]

Anchor handling is an issue with plumb bows. And they're a wetter ride. But they do often pitch less. And for a given bow fineness they'll carry weight better up forward as you have less things hanging out ahead of the waterline. In particular, a lot of boats with highly raked bows carry all of the anchor chain beyond the end of the waterline. More waterline length for a given overall length also makes a faster boat if not exceeding hull speed.

 

[sunchaser]

Ahh, the old form over function debate. The plum bow FPBs that came to fore have a lot of blue water advocates. But so do plumb bow csts, sail boats and Axopars.

 

[North Baltic sea]

Hi,

I have "blump bow" boat Nordig tug 37.

I have been over 12 feet high and short gap about 6 seconds in a wave and even though it partially splits the wave, yes it also rises the wave always safely whether you ride the following waves or the waves coming in front. The ride is smooth vs planig Hull and yes it is wet in both models when the wave is high.

I don't see it very clearly that the second would be a clearly better bow shape. Nowadays ships have an x-bow which is very effective in dispersing the force of the wave, apparently these are not yet available in Pleasure boats?

https://ulstein.com/innovations/x-bow

And Finish blumb bow boat xo is very seakeaping also Axopar...

https://youtu.be/rBu2RrNNw84


NBs

 

[Mischief Managed]

Ahh, the old form over function debate. The plum bow FPBs that came to fore have a lot of blue water advocates. But so do plumb bow csts, sail boats and Axopars.

FPBs are never going to plane on power alone (they apparently surf really well) and they are designed to maximize LWL for efficiency. They are also very specifically designed to pierce waves for a smooth ride, so I'm guessing a dry ride was never going to be a design priority. I don't think style was ever considered as much of a design factor on FPBs either, stylish, they are not... I like them though, they look mean.



I think plumb bow sailboats are also designed to maximize LWL. I don't know what a cst is.



I see a ton of Axopars and boats styled like them on the Maine coast nowadays. There's a lot of new money on the Maine coast so maybe it's form over function, I dunno??? They do look cool in a paramilitary way though. Kind of a mini-FPB style. Whenever I see them they are usually really moving out and appear to offer a decent ride and great spray protection for the crew in the pilothouse. Despite the plumb bows, I don't think Axopar and Pardo are in the same league. Pardo seems to value style over pretty much everything else.

 

[rslifkin]

Thinking about it, plumb bows on trawlers aren't necessarily new. The classic Grand Banks hulls have a nearly plumb bow with just a little bit of flare to the sides. Not as fine as some of the newer designs, but still pretty plumb.

 

[backinblue]

I've thought about this at times. With so many differnt bow styles, some exactly the opposite of the other, why haven't we settled on a "best" overall design. I've always liked the lines of a spoon bow. Some still make them, like Back Cove, but not many. Then there's the cutter bow which is like a reverse of the spoon. Here's a pretty good discussion if you have the time.

 

[mvweebles]

Thinking about it, plumb bows on trawlers aren't necessarily new. The classic Grand Banks hulls have a nearly plumb bow with just a little bit of flare to the sides. Not as fine as some of the newer designs, but still pretty plumb.

I thought the same about the GB - see the attached. Shows four bows for comparison - a Hershine 41 with extreme flare/rake; a GB 42 with very little flare/rake; and a Defever 40 with somewhere in between. I also tossed-in a Willard 40 that has some bow rake but not much flare. My Willard 36 has a wee-bit less rake but about the same amount of flare. I personally find the combination very comfortable. Too much flare/rake makes for a really active ride - I'd gladly put up with some spray and water on the bow to reduce bounce/hobby-horsing (a characteristic of the early Nordhav 46s - so much so that Leishman states in his update to Beebes VUP that he would have added 18-inches to LWL).

The West Coast salmon fleet was traditionally low-flare and plumb bow. My strong hunch was this was due to the typically heavy seas from the NW that were frequently encountered on northbound transits. A lot of flare (i.e. bouyancy) makes for a ton of pitching on the boat. Yes, a wetter ride but in all candor, with any amount of wind, a lot of flare creates a lot of spray which still gets wind-driven onto the boat. At least with a fine entry, the work-decks are a bit easier to navigate.

I'm a fan of only modest flare and bow-rake. Some of the Ed Monk motoryacht designs (Sr and Jr) where a bit too much flare/rake for my tastes. I like the GB hull design. It's a trade-off.

Peter

 

[North Baltic sea]

FPBs are never going to plane on power alone (they apparently surf really well) and they are designed to maximize LWL for efficiency. They are also very specifically designed to pierce waves for a smooth ride, so I'm guessing a dry ride was never going to be a design priority. I don't think style was ever considered as much of a design factor on FPBs either, stylish, they are not... I like them though, they look mean.



I think plumb bow sailboats are also designed to maximize LWL. I don't know what a cst is.



I see a ton of Axopars and boats styled like them on the Maine coast nowadays. There's a lot of new money on the Maine coast so maybe it's form over function, I dunno??? They do look cool in a paramilitary way though. Kind of a mini-FPB style. Whenever I see them they are usually really moving out and appear to offer a decent ride and great spray protection for the crew in the pilothouse. Despite the plumb bows, I don't think Axopar and Pardo are in the same league. Pardo seems to value style over pretty much everything else.

Hi,

Axopar and Xo vs Pardo design starting point is completely different purpose of use is completely different.

Here in Finland, there is a huge archipelago (no one knows the exact number, but about 200,000 islands), where people have holiday apartments on their own little islands.

Xo Boats was first and Axopar followed behind in design, these boats are designed as fast connection boats from the mainland to the island cottages on weekends and other times. The market leader in terms of quality and seaworthiness here is Botnia Targa, but they are quite expensive, that's why Xo and Axopar became popular here and later as an export product in other parts of the world.

It is surprising that these small factory boats made in Finland can be found on your market.

NBs

 

[mycows]

Plumb crazy

As a prior owner of both a GB 36 classic and a Krogen express 49 I would be in the plumb bow camp. We loved both boats and cruised them extensively. Many passages from the Columbia River to the San Juan islands. Neither boat gave us a concern when things got nautical…

 

[Chris Leigh-Jones]

Ahh, the old form over function debate. The plum bow FPBs that came to fore have a lot of blue water advocates. But so do plumb bow csts, sail boats and Axopars.

I'm tempted to add a little here as we are in the process of building a yacht with a plumb bow. First off this she is a displacement hull, max about 12kN cruise at 10 . I am not sure they work so well on planing hulls (Haulover perhaps?). Made for displacement hulls and for long sea voyages a la FPB intentions. The reserve buoyancy you get with a nice big flair can cause havoc in a steep head sea as she slams, stalls and the prop cavities loosing grip. A finer entry and less forward buoyancy will be wetter but less pitching and less tendency to drive the bow up/stern down. So we designed in the knowledge she will get wetter but nevertheless be more sea friendly in conditions out of the ordinary. That fine bow also gives us very extended range under more normal conditions.

Now the anchor, total pain in the rear. Those ram rods out front remind me of Triremes and we are not a Greek Admiral. We set ours to the side but will still employ a long snubber to stop it sawing at our stem as she swings. To illustrate, I have enclosed two pictures of the bow in build.

Anyhow Gents, thats my personal two pennies worth.

p.s. not sure if links are allowed but if so more details can be found on www.exploreryacht.com. Please feel free to delete this if I have transgressed any policy.

 

[Hippocampus]

When looking at any design element it’s import to consider the entire design not just one feature. With all due respect the authors opinion is applicable to one small segment of powerboat design.

In sail people became enamored of slice of pizza hull forms with hard chines. This works great in a carbon fiber ultralight but not at all in a cruiser. The production boats styled in such a matter are quite a handful in a significant seaway especially downwind or broad reaching.

You see the same thing in some recreational powerboat designs and agree with the author sometimes to detriment of handling.

However in some designs the plumb bow is just wonderful. Tugs have them and do just fine. Similarly so do the current generation of aluminum LDL boats. Going heavy full displacement and look at the commercial trawler fleet out of New Bedford you’d see a multiplicity of plumb bows. All these boats are great sea boats and have the miles to prove it. On none of them was a plumb bow just done for style points.

You need to look at the whole boat. Does it float on the water or mostly in it. What’s its half angle. Is the bow intentionally wave piercing. What’s the gyradius. What’s the reserve buoyancy at both ends. What’s the freeboard at the bow. How far is that brought aft. How does it handle green water. So many factors to consider. Good NAs draw a boat not just one feature. Any feature means all the other features change. Everything needs to work in harmony.

The weakness of this article is he doesn’t consider the whole dang boat. The strength is he’s correct some boats aren’t built for the sea but for first impressions and marketing reasons.

 

[Hippocampus]

Chris I love everything in the design you choose. Will you adopt me? I’m housebroken and fairly neat.

 

[HopCar]

I’ve always believed that form follows function. What works best looks best. Plumb bows on a fast boat don’t work and are ugly.

 

[Fletcher500]

The Axopars are very popular in our area. Dealers sell them as fast as they get them.

A similar design, larger brother, are the Sirenas. Their lack of a wake at 5 to 6 Kn is impressive.

Both boat types are mainly purchased by new boaters who rarely leave the confines of a breakwater but they serve their purpose well.

 

[KnotYet]

Chris I love everything in the design you choose. Will you adopt me? I’m housebroken and fairly neat.

I'm also available to clean up after Hippo and cook pizza from scratch if needed!

 

[North Baltic sea]

Hi,

Intrestig video UK made boat, Thunder child 2

NBs

 

[Hippocampus]

Wonder what his fuel bill is? However that wave piercing bow definitively works.

 

[backinblue]

Wonder what his fuel bill is?

As the saying goes, if you have to ask you can't afford it!

 

[North Baltic sea]

Wonder what his fuel bill is? However that wave piercing bow definitively works.

Hi

shall we say multiple here in Europe vs US. Last summer we could pay about 11$/gal.

Seriously, here is a good article about the boat's technology and performance, as well as a reference range / consumption about 2,8 gal/nm 35-40kn speed

https://www.bairdmaritime.com/work-...speed-patrol-boat-for-all-weather-conditions/

here is a really special hull, that you can see in the article, it is a multi-frame, but not traditional.

NBs