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Construction of a Pogo 50


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@apophenia  I've been very happy with the 50 ft Jenneau, in terms of a balance between waterline, availability at harbors, and maintainability, so in my mind that number was a constant.  I agre

So, actually talking about what I've been through already.  There's the research, and talking to a bunch of different owners about their experiences with various builders.  Plus, and this might n

I bet a lot of people here remember the "Construction of a Pogo 12.50" thread by @shaggybaxter a few years back.  Well, the title is probably pretty self explanatory. The build of my Pogo 50 started t

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On 10/12/2020 at 5:13 PM, Amati said:

FWIW, Disp / Length is ~ mid/ high 70’s, by my guesstimate- is the LOA the LWL?  I was guessing LOA at 48’
 

Wetted Surface?  I suppose I could try to do a similar hull on the Vacanti, but that isn’t even an educated guess....  The whole setup has the mast kind of in the middle, longitudinally, so I’d think headsails are important, but Finot-Conq do that & it works big time, no denying.  You can really pile on the SA.

But maybe WS is around ~ mid/ low 400 sq ft? ;)  

 

C0DD6243-2A36-4A96-9404-6FB7EFBD241C.jpeg

Cool graphics!

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Congrats Tumbleweed, she's out of the mold! It'll look like this soon! 

This is a 50' that was being built at the same time as Fusion, Christian took us over the boat when we came for a visit. 

This 50' was the same cabin layout as my 12.50, except the internal spaces jumped from being plenty to fucking enormous :)

That's Christian on the left, Mr composites guru... 

IMG_1907_zpsdghzryks.thumb.jpg.61d2fe5e1b3cd8607f00c7077c3c31b0.jpg

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And just to balance out the shop floor, on the other side of us was a Class 40 S3 :wub:

The ahem.. freeboard... was one of the reasons why Pogo never bothered to try and make a cruiser racer out of this version.

 IMG_1904_zps6xgbglt8.thumb.jpg.5a90037489b6cad24200bc204f2907c4.jpg

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4 hours ago, shaggybaxter said:

And just to balance out the shop floor, on the other side of us was a Class 40 S3 :wub:

The ahem.. freeboard... was one of the reasons why Pogo never bothered to try and make a cruiser racer out of this version.

 IMG_1904_zps6xgbglt8.thumb.jpg.5a90037489b6cad24200bc204f2907c4.jpg

What is going on with that companionway? I'm sure there's some sort of hard dodger yet to come, but I can't picture it.

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5 hours ago, shaggybaxter said:

And just to balance out the shop floor, on the other side of us was a Class 40 S3 :wub:

The ahem.. freeboard... was one of the reasons why Pogo never bothered to try and make a cruiser racer out of this version.

Need the scow bow of the s4 to balance it out with internal volume up front

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27 minutes ago, Ohmboy said:

What is going on with that companionway? I'm sure there's some sort of hard dodger yet to come, but I can't picture it.

Hiya Ohmboy,

Yep, hard to visualise, this is a finished version.

DSC00635-1920x1440.thumb.jpg.2f12800c915ec8fc037cd481b7873cb8.jpg 

 

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1 hour ago, Lost in Translation said:

Great looking boat, Tumbleweed.  You mentioned A/C on the prior page while on passages.  Did you get a Frigomar system or other variable system that can run on DC?  Curious for your thoughts in this area.

Not sure what the final version will be. I suggested the Frigomar with variable speed, b/c it has very low surge requirements, and can run on eco as low as 200 watts. The yard was skeptical it was up to the task, but I don't have the whole boat ducted, just the main saloon and the starboard aft cabin. I'm very interested to see how well it works.  With a 5kwh lithium battery and 600W on the solar top, theoretically it can run 24 hours on just sunshine.  I suspect that won't actually work.  The W&S hydrogenerator, in combination with the solar should be enough, though.   Then, the third power source will be the double 12Vx100A alternators, which can charge the battery bank in 2 hours.  No Genset. 

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Make sure those alts are well-cooled. Running flat-out for two or more hours, they'll either burn up or derate without adequate cooling. Between real-world alt performance and a 30 minute balancing time for the bank, I'd assume more like 3-3.5 hours to go from flat to full. 

That said, if you can keep your daytime consumption below 300W average, you can probably meet all your power needs with the real-world output of the solar plus some topping up of the previous night's battery drain. 

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Thanks @tumbleweed314.  I have a traditional Webasto unit and am intrigued by the possibilities of a system like that.  Even running a system like that at low power could potentially dehumidify the boat, but you have a very large enclosed area in that boat.  I wonder how many square feet of usable interior space. 

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10 hours ago, TwoLegged said:

I presume that the tillers are toed-in

Why would the tillers be "toed-in"?  Wheather helm?

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21 minutes ago, MauiPunter said:

Why would the tillers be "toed-in"?  Wheather helm?

With the tillers near the side of the cockpit toe-in will prevent the tiller going out over the combing when turning..

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56 minutes ago, Autonomous said:

With the tillers near the side of the cockpit toe-in will prevent the tiller going out over the combing when turning..

Ackerman geometry?  

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21 hours ago, shaggybaxter said:

Congrats Tumbleweed, she's out of the mold! It'll look like this soon! 

This is a 50' that was being built at the same time as Fusion, Christian took us over the boat when we came for a visit. 

This 50' was the same cabin layout as my 12.50, except the internal spaces jumped from being plenty to fucking enormous :)

That's Christian on the left, Mr composites guru... 

IMG_1907_zpsdghzryks.thumb.jpg.61d2fe5e1b3cd8607f00c7077c3c31b0.jpg

Why is it that there are always pics like this during a build? 

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There's a difference between tiller toe-in and rudder toe-in.

I agree with other posters regarding the apparent tiller toe-in.  It is probably to avoid the tiller on the outside of a turn (port tiller when turning to starboard) from riding over the cockpit combing or pinning any crew member sitting there against the combing.

Rudder toe-in is completely different … as a prior poster suggested … Ackerman geometry.  Just like the front wheels of your car, they don't point parallel when turning.  The outer rudder in a turn (port rudder during a turn to starboard) must pass through an arc of greater radius than the inner rudder.  So Ackerman geometry of the rudder linkages will point both rudders in the direction of the tangent to their radius of turn.   This ensures that both rudders exert the same turning force.  If they didn't toe-in, they would put an unequal strain on the rudder posts and each would be trying to steer the boat in a slightly different turning arc.  However, the toe-in of rudders looks different from your car's front wheels because the rudders steer from the stern of the boat, while the front wheels of your car steer from the front of the car.  The principle is the same though, just think of your car driving in reverse.

Many boats don't bother with Ackerman … they figure that rudders are pretty inefficient anyway, so such refinements achieve little.  On your car, they prevent uneven tyre wear by keeping the tyre pointing along that tangent to it's radius of turn.

I believe that most dual rudder set-ups have some natural toe-in, even when steering straight ahead.  I'm not sure of the reason for this … undoubtedly someone of greater knowledge can enlighten us.

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  • 1 month later...

Deck ready to be attached.  (See below)

Additional changes to specs since last update -

  • swapped out SS shrouds for Future Fibers EC3 carbon. 
  • added a diesel heater. 
  • Scrapped the radar/stern post. 
  • Switched to new B&G Nemesis screens by companionway
  • Specced out a removable bench for the companionway
  • Switched starting battery to lithium (thanks to @svitale for pointing that out on his build)
  • Added big ass stickers on the side, similar to @shaggybaxter
  • Clarity around the winches, especially for the runningbacks. Upgraded to performa and the main cabintops will be 3 speed. 

Starting to plan out the transit. Delivery date in September. Gonna need to boogie to get shakedown done and move South before weather turns squirrely.  

 

deck_attach_2.jpg

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Bench for the companionway is a great idea. I have sat there for thousands of miles. Sometimes with a pillow on the hatch for those special watchkeeping periods :-) For many of those miles I've though about making a cushioned seat. But then I forget.

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So where is your radar going to go now?  I can't recall … did you go for the aluminium or carbon mast?

While a stern post or arch is a pain for windage, all those extras, like radar, backup antennas, wind generator, solar panels, satellite dome etc., gotta go someplace.  It would be nice to have an easily removable post/arch for racing, that can carry the gizmos for cruising.  Or has a low windage arch design slipped by under my radar? 

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On 2/26/2021 at 7:38 PM, tonydove said:

I believe that most dual rudder set-ups have some natural toe-in, even when steering straight ahead.  I'm not sure of the reason for this … undoubtedly someone of greater knowledge can enlighten us.

Would be beneficial to align the rudders with the local flow at speed. That could well be a somewhat outward flow at the corners of these wide-aft hulls. Or maybe it is best that the leeward submerged rudder does most of the work...the windward more passive. Would require some careful experimentation to determine.

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While I have no experience with twin sailboat rudders I do know a good way to align twin outboard motors is to disconnect the tie bar and let the motors find their own alignment. Watching the wake is useful too but that takes experience with that hull type.

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4 hours ago, Borracho said:

Would be beneficial to align the rudders with the local flow at speed. That could well be a somewhat outward flow at the corners of these wide-aft hulls. Or maybe it is best that the leeward submerged rudder does most of the work...the windward more passive. Would require some careful experimentation to determine.

As the boat heels, the centerline continues to run through the bow, but the aft end of the centerline migrates towards the leeward quarter, creating a diagonal effective centerline. Without toe, the leeward rudder would generate a lot of weather helm in what looks like a geometrically neutral position on deck.

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Almost. As those big fat bastards tip the centerline moves to leeward at the stern as you say. That's not a problem for the leeward rudder, that's doing most of the driving, as it just goes where you aim it. The windward rudder however if getting every more out of wack, trying to bear off and dragging right up until the point it comes out of the water and stops being a problem. It's the windward rudder causing the problem. The weather helm on the leeward rudder is purely a function on boat set up and sail trim 

The fact that the amount of toe in required changes as the boat tips more is why the racing boats that can change it while they sail.

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18 hours ago, tonydove said:

So where is your radar going to go now?  I can't recall … did you go for the aluminium or carbon mast?

While a stern post or arch is a pain for windage, all those extras, like radar, backup antennas, wind generator, solar panels, satellite dome etc., gotta go someplace.  It would be nice to have an easily removable post/arch for racing, that can carry the gizmos for cruising.  Or has a low windage arch design slipped by under my radar? 

Nowhere. I scrapped the radar.  No sattelite dome.  Solar panels are on the coach roof house.  No wind generator.  Watt and Sea Hydrogenerator gets me power under sail.  

I detest the idea of radar on the mast, disturbing the windflow in the slot. Worse -- I've torn two sails racing hard and getting the trim in as we go through a tack.  

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I agree with you about radar on the mast … troublesome to say the least (unless on the mizzen of a ketch).  However, I do like radar.  Having done some SAR with Coastguard at night … it is invaluable.  I'm curious why you scraped the idea of a stern post for it … that would seem the best of the options.  A central post doesn't seem to bother the Volvo racers and they even had one (for a different purpose) on all the Americas Cup AC75s … so it can't have too bad a windage factor.

I like the idea of getting rid of the SS shrouds but I'm curious why you went with carbon instead of dyneema … dyneema seems more robust.

Anyway … it sounds like a great build you have going … best of luck with it.

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45 minutes ago, tonydove said:

I agree with you about radar on the mast … troublesome to say the least (unless on the mizzen of a ketch).  However, I do like radar.  Having done some SAR with Coastguard at night … it is invaluable.  I'm curious why you scraped the idea of a stern post for it … that would seem the best of the options.  A central post doesn't seem to bother the Volvo racers and they even had one (for a different purpose) on all the Americas Cup AC75s … so it can't have too bad a windage factor.

I like the idea of getting rid of the SS shrouds but I'm curious why you went with carbon instead of dyneema … dyneema seems more robust.

Anyway … it sounds like a great build you have going … best of luck with it.

I also like the idea of radar, I have it on my current boat. I've even used it twice. But the reality was we just couldn't find a place for the post that didn't interfere with runningbacks, lifeboat, etc.  I think the designer was probably saving me from myself and stuck to the original design spec, which is:  "As far along the outward envelope of racer as a racer-cruiser can possibly be".  Very few items not along that spec have made the cut -- probably 100kg total in equipment, and every one has been with a good amount of hand wringing. 

Also, the designer not-so-secretly hates the aesthetic of the post. So, it was probably doomed from the start.  

I'm not expert on the various shroud materials available, but my superficial understanding is that dyneema is subject to creep, only a little, but enough to be a serious pain in the ass on upper diamond stays.  I think this can be mitigated, but not eliminated by pre-stretching.  Admittedly biased marketing materials have impressed upon me the durability of the carbon shrouds as well -- claiming that they are still viable even with 25% of strands damaged.  Maybe true.  Maybe not.  At any rate, in a gale, when some piece of kit goes rogue and starts banging shit,  my gut tells me I'm going to be less worried about the carbon.  

 

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