Survive The Savage Sea - How would a GRP boat fair?

[seanfoster]

I've just read Dougal Robertson's 'Survive The Savage Sea' (been meaning to for a long time, and if you haven't read it then I seriously recommend it!)

His wooden boat was struck by a killer whale (apparently being chased by another two) which pushed in and split a section of planking. "Her hull had taken a full minute to sink beneath the waves"

He wrote "a modern boat, constructed with less regard to brute strength than Lucette, would have sustained heavier damage and sunk even more quickly"

Now I fully understand that this will no doubt cause a lot of arguments and points of view, but how true is that statement? I presume he was talking about GRP boats? How often do whale strikes occur? What damage is usually sustained? What other objects cause a yacht to sink?

I ask with interest, as I plan to do a transatlantic circuit within the next few years and all being well a circumnavigation soon after that.

 

[Ludd]

Having read the book years ago,it's something I've often wondered.Would a heavy old MAB like mine stand up to it better than a modern lighter boat,or would the lighter boat be deflected,not offering an "immoveable object" scenario?
Probably wouldn't matter, as the "survive" bit would be beyond most of us!

 

[Deleted member 36384]

The problem with wooden planked boats is that they are made of planks! Therefore there are more possibilities for something to leak compared to a non planked hull.

There was GRP yacht racing to South America from South Africa (IIRC), about early 80s. It sunk quite fast and I dont think they found the source of the leak. However, as the yacht rolled over they saw a longitudinal split along the keel to hull area.

Check out "Safety and Survival At Sea" a book full of stuff like that. Also "Total Loss", which is where I am sure the account came from.

 

[Ludd]

The problem with wooden planked boats is that they are made of planks! Therefore there are more possibilities for something to leak compared to a non planked hull.

There was GRP yacht racing to South America from South Africa (IIRC), about early 80s. It sunk quite fast and I dont think they found the source of the leak. However, as the yacht rolled over they saw a longitudinal split along the keel to hull area.

Check out "Safety and Survival At Sea" a book full of stuff like that. Also "Total Loss", which is where I am sure the account came from.

Yes ,I suppose every join is vulnerable in planked construction.
Now you mention it ,I remember reading that,but can't remember where!
Thinking about it,my long keel fg hull would be less vulnerable than a bolted on fin and my rudder likewise.
I am,however ,in no hurry to put it to the test!

I think the biggest danger now would be from semi submerged containers,rather than whales.

 

[seasolutions]

the biggest factor in resisting inpact damage has got to be strength of construction not type;

ie a lightly built wooden boat eg one of the racing classes, is going to fair less well than an MFV similarly a cheap day-sailer will be less tough than a heavy offshore cruiser.

then of course you have to consider the type of inpact:

wood and steel are very resiliant (springy) but as the previous post rightly states, cavrel and clinker boats are made of lots of parts so are only as strong as their fastenings,

GRP is not as resilient as these, and it is particularly poor in abrasion, but as the boat is all one piece (except for the keel) even if it is cracked, it will probably still hold together

if your main concern is crashing into things then a steel boat has got to be the way to go, with a GRP boat second (possibly third to aluminum) but if your planning to spend a long time scraping over coral heads or bashing against an old stone quay then wood may come out ahead.

ultimately though a solidly build boat of any material should be ok in most situations, but a lighltly built one less so.

 

[Deleted member 36384]

I think that the new edition of Total Loss (paper back, new edition 2008) has some statistics that would back up your container risk, Ludd. Its a good read and updated quite significantly from the first edition.

 

[Baggywrinkle]

A Bluewater Capable Yacht.

No matter what type of boat you have, something out there could sink it (unless it's an Etap) Making a purchasing decision based on which material may or may not fare better for your chosen disaster scenario is, to my mind, an academic pursuit. Material choice comes a long way behind boat design IMHO.

Fire, gas explosion, roll over, container strike, whale strike, ship strike, lightning strike, freak wave, maintenance error, gear failure, pirate attack, iceberg, navigation error, etc. etc. etc..... pick your doomsday scenario - all can be fatal and pretty much every construction method ever used has met its nemesis one way or another.

I think the author was voicing an opinion based on what he believed to be true at the time. Every construction method has its pros and cons but the design will count more than the materials - exposed spade rudder vs. skeg, long keel vs. deep fin.

I found the book "The Voyager's Handbook" by Beth A. Leonard a good read for someone planning a circumnavigation, particularly Chapter 3 'A Bluewater Capable Yacht'. If that doesn't help try the Liveaboard Forum - and may your bilge never fill with water faster then you can pump it out

 

[photodog]

I think a GRP boat would have sunk as well with a big hole in the side.

Of course, if they had a EPIRB, like the family in the South Atlantic yesterday.. they would not have spent a month or so eating turtles and smelling each others stinky feet.

 

[paulm299]

I think a GRP boat would have sunk as well with a big hole in the side.

Of course, if they had a EPIRB, like the family in the South Atlantic yesterday.. they would not have spent a month or so eating turtles and smelling each others stinky feet.

I hit a Turtle in an Enterprise once .

 

[photodog]

I hit a Turtle in an Enterprise once .

Thats not very nice... did he tack across your bow?

 

[BruceDanforth]

I don't really think eating turtles would be much of a goer, I've seen about 3 per ocean. I've seen a whale swim alongside the boat I was on (60 footer) and they are pretty big beasties. Apart from the air out of it's blow hole being pretty fishy it was quite an agreeable thing which is just as well as it was big enough to reduce us to flotsam if it was angry.

 

[TradewindSailor]

As stated above a steel or aluminium yacht would probably survive an attack by a whale or other large marine creature. This is in general due to the problems with fabricating with steel and aluminium, and also corrosion, requiring the plate thickness to be thicker than the design loads actually require.

GRP and sandwich construction are built much closer to the design strength. But then that isn't the whole picture either.

Generally steel yachts take huge punishment before getting holed ..... even if they do end up like a crumpled coke can. It rather depends on the build quality, particulary welds.

Aluminium tends to shear, particularly at bulkheads, and also welds can fail.

GRP - it depends on the quality of lay-up. If punched hard enough to shear the grp, does it loose material, or does the hole close up after? If it looses material the hole may be difficult to plug. If it closes up the leakage may be able to be matched by the bilge pumping capacity. I've seen examples of GRP hulls that have had holes punched in them (usually by falling off their stands on the hard, but sometimes they have been recovered from the depths) ..... there is no way these boats would have survived an impact with a whale.
I've seen an Island Packet after it was driven onto a reef after a storm. It only needed minor repair.

Foam Core - A lot of people have suggested that it wouldn't stand a chance, but I disagree. I rather suspect that a lot of impact energy would be taken by displacement of the foam, and the integrity of the hull could be maintained by the inner skin. I have seen a Seawind Catamaran that has wound up hitting Granada survive to sail to Carriacou for patching up ...... but then it didn't have a lead keel.

As for the type of damage whales can inflict look at J/World look here:
http://www.sail-world.com/USA/index.cfm?SEID=0&Nid=62778&SRCID=0&ntid=0&tickeruid=0&tickerCID=0
I am a little surprised that the boat sank though ...... probably to a poorly engineered rudder stock. The rudder should be designed to break off before a hole is ripped in the bottom ..... or a watertight bulkhead placed before the stock.

 

[30boat]

I don't really think eating turtles would be much of a goer, I've seen about 3 per ocean. I've seen a whale swim alongside the boat I was on (60 footer) and they are pretty big beasties. Apart from the air out of it's blow hole being pretty fishy it was quite an agreeable thing which is just as well as it was big enough to reduce us to flotsam if it was angry.

They're quite common around Madeira.I sail there regularly from the Algarve and bump into them all the time.It's funny to see them twisting their necks looking at us as we go by.

 

[Woodlouse]

The best material to use if you intend to go ramming whales, reefs, rocks, turtles etc is actually Ferro Cement. Ferro will only ever crack, and chip and the amount of water taken in will be relatively small compared to an outright hole. The punishment required to actually hole it would be incredible.


As for GRP vs wood, I think a fair test would be to get a stout man to hit a GRP boat and a wooden boat with a sledge hammer in similar areas on the hull and see the damage. I reckon you'd see cracked planks in the wood, and big holes in the fibre glass.

 

[mike_bryon]

I met a guy in Horta Azores on passage from Venezuela bound for France with a 1980s grp boat around 30 feet who had survived a whale attack. He and his crew arrived shipping a lot of water and were exhausted from days of bailing and shock. His boat was lifted and repaired and the press eventually reported his story.

He was followed by the whale for a day or more before it attacked and it attacked twice the first time sticking the hull the second time the prop shaft bending it and causing the ingress of water. He was able to slow the leak by packing a sleeping bag under the shaft. He had no life raft.

 

[Boo2]

The best material to use if you intend to go ramming whales, reefs, rocks, turtles etc is actually Ferro Cement. Ferro will only ever crack, and chip and the amount of water taken in will be relatively small compared to an outright hole. The punishment required to actually hole it would be incredible.

That's c0ck. Look at what happened to this families' ferro hull when it "landed on a pile", from the text it seems the boat wasn't even moving at the time

Boo2

 

[Baggywrinkle]

Ferro boats ....

It's interesting to see what happes to ferro-cement when hit by lightning. The charge travels through the wire mesh until it finds the thinnest part of cement (least resistive) and then it creates a massive exit hole where the cement gets blown out and the boat sinks. I know of one person this happened to off the coast of south america. Boat went down so quickly they didn't have time to grab anything. Carbon fibre explodes too unless coated with a conductive layer.

Just as well wales don't know how to use van der graaf generators.

 

[timbartlett]

It's funny, but I know quite a few people who have sailed the Atlantic (and beyond) in boats made of wood, GRP, and steel, and although one was dismasted, none of them have sunk. But I guess that's not unusual enough to be news, and not exciting enough to make a book.

 

[jwilson]

That's c0ck. Look at what happened to this families' ferro hull when it "landed on a pile", from the text it seems the boat wasn't even moving at the time

Boo2

Your example really does not look like a very well built ferro boat. Done well, ferro is incredibly tough, done badly it can be rubbish.

 

[TradewindSailor]

Your example really does not look like a very well built ferro boat. Done well, ferro is incredibly tough, done badly it can be rubbish.

For all those ferro-cement boats that were built to provide cheap cruising, there are not many to be seen on the cruising circuit ....... unless you count the ones hidden under the pelican guano. I've seen some well maintained examples .... but I doubt very much that even they would stand much beating on a reef, or pummeling from a whale.