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Old 14-04-2015, 09:21   #91
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Re: Boat for polar cruising

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Originally Posted by Tensen View Post
I don't think there's anything wrong with a composite hull for polar exploring, providing that it's been built properly for the task. (Admittedly, whether it's possible to find such a hull is an entirely different question...)

Pound for pound composites are far stronger than steel or aluminium. Steel's most redeeming quality is that it's cheap.

It wouldn't be difficult to make a composite hull that can absorb as much energy from an impact as a steel hull. It just wouldn't be as light as most composite hulls (but would be lighter than steel of course).
Metal hulls have fracture toughness and hardness which allow them to absorb impact energy and abrasion. Steel is particularly good in this respect especially the micro alloyed low carbon variants. Steel also has an infinite life when cyclic loads remain below a specific level. Aluminium alloys have a finite life when subjected to cyclic loads.

Composites are poor performers when contact with hard and abrasive surfaces are encountered. No engineer would specify composites where repeated impact is encountered. Composites are however a great choice for safety cells which must survive one impact event. Motorsport and aircraft are well known examples.

Composites have a much higher specific stiffness than metals. This is purely a function of specific density. This one of their most desirable properties.

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Old 14-04-2015, 10:33   #92
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Re: Boat for polar cruising

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Surely you are thinking FG, maaaybe alloy, not steel?
Well, so many tons (metric) @ speed in meter per square seconds...easy to calculate the acceleration...water is not a brick wall, so boat does not go to a stand still in less than a sec, so energy dissipates then you add another couple of tons of water pushing on your sails....better have a fuse somewhere...


Given the choice...a mast makes a perfect fuse on whatever deck material it seats, don't you agree ?

Then the question is, steel, what steel ?
See automotive and corrosion protection, I am fine with this steel.
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Old 14-04-2015, 11:46   #93
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Re: Boat for polar cruising

Nobody underestimating forces from water. We do understand masts are not designed for being pushed under the keel.

And YET.

If a Contessa 32 can survive 2 rollovers with her mast still up.

If an Overseas 35 can survive a rollover with her mast still up.

If our own 26' plasticky bendy 30 y.o. craft can survive a 135 and back ... with her mast still up.

Then a boat designed for extreme adventures should stand a chance of not losing her rig either. Or at least not losing all of it. (A third of a mast is better than no mast at all...)

I have seen images of that boat and I have seen a video on Norwegian TV. Aside from dramatic mast loss (OK, maybe could not be avoided) the boat was complete mess: water inside and debris floating everywhere as if something exploded.

Since we know adventures like this may happen in latitudes like that, a boat should be designed and set up as if this kind of event was taken for granted.

Otherwise, why not go in a folkboat instead. Cheaper boat, same result.

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Old 14-04-2015, 13:36   #94
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Re: Boat for polar cruising

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Originally Posted by Claude_Marie View Post
Well, so many tons (metric) @ speed in meter per square seconds...easy to calculate the acceleration...water is not a brick wall, so boat does not go to a stand still in less than a sec, so energy dissipates then you add another couple of tons of water pushing on your sails....better have a fuse somewhere...


Given the choice...a mast makes a perfect fuse on whatever deck material it seats, don't you agree ?

Then the question is, steel, what steel ?
See automotive and corrosion protection, I am fine with this steel.
Claude,

You lost me. I thought you were advocating that it's better to have the mast fail rather than have the deck ripped open.

I don't see much chance of my deck being ripped open in any event. Deck stepped masts with welded in compression post.

So why should I want a "fuse"? What is the fuse protecting?

Re your comments about automotive and corrosion were opaque to me. Guess I'm just dense.
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Old 14-04-2015, 14:19   #95
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Re: Boat for polar cruising

Here is a nice little polar boat... she's been to Greenland and Jan Mayen...
Sumara of Weymouth - the Vertue Class
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Old 14-04-2015, 17:27   #96
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Re: Boat for polar cruising

I am not sure decks open all that often. Not on strong boats anyways.

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Old 15-04-2015, 00:44   #97
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Re: Boat for polar cruising

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Claude,

You lost me. I thought you were advocating that it's better to have the mast fail rather than have the deck ripped open.

I don't see much chance of my deck being ripped open in any event. Deck stepped masts with welded in compression post.

So why should I want a "fuse"? What is the fuse protecting?

Re your comments about automotive and corrosion were opaque to me. Guess I'm just dense.

Automotive steel :
Yield point/ Elastic limit :
20 years ago : 300-350 MPa
10 years : 400-700 MPa
Currently : 1300-1500 MPa
Future : 2000 MPa.

Current car body embed : 20% of these "high grade" steels.
2020 : 30% of high grade.
2025 : 40% " ".

Benefit : Savings in weight.
Downside : Welding problems.

Question : Do shipwards have acknowledged those tremendous improvements ?
Shipward building commercial vessels probably.
Building recreational vessels ?


Why do you want a fuse ?
Energy has to absorbed somewhere....if transmitted to your hull...you want lockers doors looking like safe doors.

Remember of " the other century" american cars ?
US Automotive engineers believed that making bullet proof cars was the best way to protect people inside.
Europeans made "soft" cars instead.
Which solution proved best ?
I am happy with a car which front part behaves like a fuse and absorb the energy should a collision occur.
I happen to think the same with boats.
If I am left with enough mast to set a jury rig, fine.
Sorry for being European.
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Old 15-04-2015, 00:46   #98
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Re: Boat for polar cruising

Edit : Sent same message twice.
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Old 15-04-2015, 03:30   #99
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Re: Boat for polar cruising

I don't think getting totally hammered is really an issue in polar regions 'in season'.
However.. expanding upon the 'fuse' concept....

Back before about 1850ish square rigged ships had wooden spars and fibre rigging... the ship would lose her rig but survive.
Then along came iron ships with iron spars and steel wire rope for rigging.... they just ended up on their beam ends and sank with their rigs intact.....

Deck smashed open etc? it may not happen often but it does happen.. a CF member lost his yacht offshore from Rio Gallegos about 2 years ago from such an incident ( deck house gone buggeroff) ... lost his rig at the same time mind you....
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Old 15-04-2015, 03:33   #100
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Re: Boat for polar cruising

Quote:
Originally Posted by Claude_Marie View Post
Why do you want a fuse ?
Energy has to absorbed somewhere....if transmitted to your hull...you want lockers doors looking like safe doors.

Remember of " the other century" american cars ?
US Automotive engineers believed that making bullet proof cars was the best way to protect people inside.
Europeans made "soft" cars instead.
Which solution proved best ?
I am happy with a car which front part behaves like a fuse and absorb the energy should a collision occur.
I happen to think the same with boats.
If I am left with enough mast to set a jury rig, fine.
Sorry for being European.
And how often the sky has falled on top of a boat :P
Seriously, the speeds are totally different magnitude if we talk about cruising sail boats vs cars. If it were a problem shouldn't we use seat belts and airbags too..
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Old 15-04-2015, 03:38   #101
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Re: Boat for polar cruising

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.......If it were a problem shouldn't we use seat belts and airbags too..
Bet they could have used them on that Volvo boat...
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Old 20-04-2015, 11:42   #102
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Re: Boat for polar cruising

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And note his personal boat is steel... and this is who will be building the Adventure 40 (FRP) for John of Morgan's Cloud... claims $200K for a sail-away high latitude yacht.
Incorrect. No claims have been made that the Adventure 40 is ideal for high latitude sailing.

On the contrary, if you check Adventure 40 faqs, you will see the following:
Quote:
Q: Is the Adventure 40 to be a go anywhere high latitude boat like the ones you often write about on this site?

A: The Adventure 40 will be a boat for crossing oceans, or circumnavigating the planet, as well as wonderful for a weekend on the Solent or a two week cruise to Maine.

However, the boat will not be optimized for the high latitudes. That simply can’t be done at the price point. Having said that, I see no reason that the Adventure 40 should not cruise to Svalbard, Labrador, or even the west coast of Greenland.
Similarly, at Adventure 40 - an overview, we find the following:

Quote:
The boat as it comes from the factory and after an ultra-short two week shake down cruise, will be capable of taking a couple with occasional guests around the world in safety and comfort. She will also be a fine weekend cruising boat for those who have to keep working at their day jobs while they plan their escape…. [T]he boat will be designed to appeal to a wide audience—the Adventure 40 is not a specialty expedition or high latitude boat, one of those already exists (linking to a discussion about the Boréal 44).
While I am not personally convinced that there is any real need for the Adventure 40 - proven offshore-capable boats are already available, either secondhand or 'off the shelf' - I do find John Harries' various sailing articles to be thoughtful written and generally helpful. Further, he tends to avoid dogmatic statements, going out of his way to state that his preferences reflect his own experiences and may not be generally applicable.
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Old 20-04-2015, 15:25   #103
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Re: Boat for polar cruising

About the Adventure 40 Boat

What follows has nothing to do with my respect for the designers or the site owner where the Adventure 40 is described in detail. They have both got great credentials for "adventure" sailing and many miles under their keels etc. I respect that experience and if given the chance to meet them or sail with them, I am sure I would enjoy it and learn from them.

My remarks are focused on what is positioned or mentioned as a suitable boat and my questions are related to what others see in the boat that distinguishes it or places it above other boats.
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The Adventure 40 does not impress me as a standout boat for "adventure" or "high latitude" sailing. I spent some time reading as much as possible on that site, and the more I read about the development (slow) of that fiberglass boat (still unbuilt AFAIK), the less interesting that boat became, to me. Why? Because I thought the concept was to build an "adventure" or "expedition type" boat (polar cruising, etc.) for a reasonable or lower cost.

I suppose the "Adventure" name got me thinking one thing initially, but the blog posts (on that site) got me thinking something else over time. This is probably a simple case of "unmet expectations."

But it is also probably something to do with how the boat is positioned and mentioned by others and in the context of a site that seems focused on high latitude sailing.

The quotes posted above (by Svanen) from that site make it clear that the Adventure 40 boat is NOT intended as a polar type boat or high latitude or expedition boat.

From reading that site, it seems the Adventure 40 boat has been "minimized" (my view) to fit the price point and that is preventing anything special about the boat to the point that there was mention of "no options" and rather plain interiors (and too little budget to include a watertight door etc.).

Consequently, I fail to see the appeal of it. Perhaps someone else here can clearly identify what it offers that other boats do not at that price point.

Actually, with a $200K budget, I think I would find an appealing boat (most likely used) that would eclipse the Adventure 40. But we all have different tastes, needs, and opinions.

AFAIK, the Boreal 44, on the other hand, has a different design concept and materials (metal) (and cost), even if it has the same designer and yard etc. The Boreal 44 is a very interesting boat (to me) and in it I do see a boat that looks built to go to remote places etc.
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Old 20-04-2015, 16:03   #104
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Re: Boat for polar cruising

Capsize and Sinking of Steel Monohull During Circumnavigation

Since some of this thread has been discussing the risk of capsize and the possible loss of a mast (and possible water ingress from missing mast or hull/deck seams), I think some might find it interesting to read an account by one of the CF forum members whose boat was lost due to a capsize off Argentina in an area known for rough waters and dangerous conditions at sea.

The boat was a 42 foot steel boat in what appeared to be very good condition prior to the capsize. If you read his blog, you can see that the boat got a lot of care and attention and looked very nice. The owner had almost completed a circumnavigation and had many miles of successful sailing alone. The boat had been refitted and updated and serviced during his voyage around the world.

The boat rolled (which injured the owner with a blow to the head) and eventually sank. The owner and his one crew (a good friend) were rescued by helicopter at night in rough conditions while floating in the water. Scary stuff!

I did not read about the sinking of his boat until after reading much of his blog, because I came to his blog from a link to another earlier part of his voyage. I very much enjoyed his blog about his travels, including his many photos of places he saw, and enjoyed his good humor and attitude about sailing and what he saw. It was complete surprise to me when I came to the last blog entry (January 2014) that told of his loss of his boat.

https://petepowell.wordpress.com

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Here are a few quotes from the owner (Pete Powell, AKA Rigormortis on CF) of the yacht La Rosa.

"In retrospect, I am guessing the wave heights to be 8-9 metres during the 3 days of hard blow that we found ourselves in. No doubt the wave(s) that rolled us were slightly higher and also breaking."

The boat rolled into the inverted position and hung there, stable, for 15 seconds or more (according to my shipmate). I think most of the water came in from the companionway during that upside down time.

That hatch had a heavy Bomar sliding metal/plastic cover and drop boards. I had one wooden drop board in place and was using a 1/4" plexiglass drop 'board' to keep most of the spray out of the cabin before we rolled. All parts of the companionway closures were gone and water flooded in.

When we righted (I think another big wave snapped the mast and she righted) we had about 1 m of water inside.

The dogs for the forward and centre hatches were gone and both those hatches (Bomar) were cracked and no longer secured. Water sloshed in as we sloshed about. Water came in, as well, through the heater chimney hole--chimney gone.


The sink in the bathroom, the sink in the galley and two others used to discharge bilge water became below water line as we rolled and settled.

On deck the mast was down, partially on deck. It was a deck-stepped mast and it broke off about 3 feet from coach roof level.

No water came in from there; the hard dodger and bimini were gone; the steering pedestal was broken off; wind vane, too; my new radar and solar panel frame was still standing--well made in Buenos Aires!

Most floor access panels were gone and that made managing down below very hazardous--I have to scars to prove it. **** was everywhere, as you can imagine.

Advice: make sure all aboard know where the thru hull shut offs are. Do a run through on how to activate the emergency beacon when you have time and good light. Don't get knocked out. More will probably come to me."

Pete

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I found Pete's notes on this forum in another thread. I have bolded a few key points that I think bear noting when discussing what could happen even in a strong (steel) yacht that was seaworthy and had been successfully sailed almost completely around the world.

Notice that the companionway was the source of most of the water coming into the boat. But also notice he mentions the through hulls for the sinks, because those were not shut (his crew did not know where they were or could not find them in the dark and water and chaos of the interior of the boat after the roll).

Putting it simply, you might survive a roll of 360 degrees, but may still sink in a boat that has a sound hull.
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Old 21-04-2015, 08:03   #105
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Re: Boat for polar cruising

IMHO

Dreaming up a fine polar boat is a fine thing. One that will not get flooded only because she gets rolled (yes, this is quire simple: you want a doghouse with watertight hatch to the companionway and another watertight door to the cockpit). Etc.

But how many such boats are around. Well. A handful. But only one.

And they are not the best tool to weekend cruise on the Solent either.

Reinventing the wheel claiming B40, B50 or B60 boat is good for this or that? No, thanks. One look at Dick Zaal's website shows boats like this, by experienced designers, have been around for decades. Buy the plans, have yours built, go cruising.

Now what I know for sure is that many of ice lovers simply set for a knock off Roberts design, some make theirs stronger, and off they go. To Svalbard, Iceland, Groenland, Patagonia. They look rusty after one season, then they get painted over and they go again.

There sure is a nearly perfect tool for everything. There sure is a best tool for any adventure. But something less than perfect will do too and, in fact, may constitute a considerable portion of the polar cruising fleet.

b.
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