Sinking!!

[hlb]

An article on PBO sparked my thoughts on this one.
What dose offshore mean?
How rough is rough?
I was coming back from Brixham to Plymouth last week. The forecast said F 6 maybe 7 but going worse over the next two days.
I set off through Lyme bay doing 16 knots, which we could just manage without going airborne.
Just after Dartmouth a Sports cruiser about the same size or smaller than my Princess 35. Past us like we were stopped. Waved and disappeared into the overfalls around the headland.
We slowed to 10 knots and even 8 at times. We went downstairs because the sea was threatening to come over the fly bridge. We then had deep green sea over the window screen for minutes at a time. Then we’d go air borne and crash back into the sea. The boat felt like it was going to break in two at times and I thought we were going as fast as sensible. The anchor broke its securing rope and bent and dislodged the pin holding it down and pulled the chain off the windlass.
Then course there’s the lobster pot buoys looming up on the rare times they were visible.


I’ve been sailing powerboats in the Irish Sea, Bristol Channel, Scotland and France for the past 12 years or so and this was as bad a sea as I have seen and my boats supposed to have legendary sea keeping.

On radioing Salcombe from about two miles out, To enquire about the bar I was informed that the boat that past us was already moored up!!

Now the question.

Am I getting to old? Is my boat crap.
It’s only about ten miles from Dartmouth to Salcolmbe.
The bloke must have been doing a good 20 knots through this crap to arrive when he did.
Are boats indestructible?
Overfalls arn’t like being in just a rough sea its like being in a bloody washing machine. There’s no direction to it.

Ok after passing Salcolmbe we were back up to 20 knots but still thrashing about allot going West against a f6 from the South West.
All the way to Plymouth.
Now I don’t think that’s bad.

So how did he do it. The boat was nothing special. Maybe a Princess or Fairline.

Or was he just nuts!
How much boat do you reckon was left!!
Or as I said. Am I just getting Old and too cautious.






Haydn

 

[ianphillips]

I can't speak for a full planing hull of this size, but we have an Aquabell 33 (semi-displacement) and in those conditions 8-10 Knots would be about the most uncomfortable speed to choose. I find a small amount of slamming is infinately preferable to wallowing from one crest to the next and therefore make every attempt to stay on the plane and keep the nose up!

We learnt our lesson in a large following sea coming out of Portsmouth Harbour a few years ago and broached on several occassions, all because I didn't have the nerve to open the thottle. As we gained confidence, the boat's behaviour was transformed. In our boat it is vital to keep ahead of the sea and yes there have been many times when I've wondered whether we are going to continue the downward plunge into the back of the next wave, but she so far she has always
stopped short of shipping solid water. This maybe the benefit of a semi-displacement hull.

In a short steep head sea, again I find it best to keep on the plane, even if its just 12-13 knots. Yes she slams a bit, but at least you are riding on the sea, rather than under it. In longer head seas/swells I find 15-16 knots most comfortable.

If it cuts up rough, I find the best helm postion is on the flybridge; wet yes, but at least you have some all round visibility. Good wet weather gear will keep you warm and reasonably dry at this time of the year. I use a waterproof handheld GPS and only go below in thick fog, to gain the benefit of the radar.

As for the durability of boats, I have often wondered how much punishment a hull can take and there have been occassions when we have dropped off a wave and crashed into the trough with a back jarring slam, but in reality with our type of vessel, this seems to happen just as often at 10 knots as it does at 15!

Perhaps a planing hull is different?

 

[hlb]

Yes but you miss understand Ian.
I agrea that in a following sea 22 knots with a f7 behind you is lovely and comfortable. Just as long as you dont slow down!!
But I'm talking about overfalls and I agrea 6 knots would have been alot more sensible. Infact it would have made allot more sence to have taken the long route round the outside of them.
I'm well aware of the preference to keep a planing boat on the plane as long as possible. But this is ten foot lumps all over the place.

Haydn

 

[ArthurWood]

Haydn, you're a tough lot on that side of the pond. Anything over 3ft seas here in Florida and no-one ventures out!! Home of the Brave etc.

 

[duncan]

I would venture that he (the other vessel) had already been out and established how the sea state and his hull worked best re speed.
Being based at Poole I have Old Harry, Peveril and St Albans to play with and, esp Old Harry (smallest) often go through slowly first then round and round finding the best speed / trim for the conditions. I am only 25ft and tend to find a speed between 18 - 22 knots when it's lumpy but....when you get it wrong ......normally the missing wave is the worst situation.
Un practiced I am with you @ 8-10knots (and also if others on board).

 

[longjohnsilver]

I was out yesterday returning from Lyme Regis to Exmouth expecting a SW 3-4 0nly to find a 5-6 SSW with sevens being mentioned! Mine is a semi displacement 32' with a single 215 hp. At first I tried between 5 and 6 knots as the worst of the sea was just off the nose on the port side with some quite nasty patches of waves which we estimated to be approx 10' high. We rolled like a pig at these speeds and it was only after a while that I decided to open her up a bit to 1700 revs and 8.5 knots. This did the trick and virtually stopped the rolling and with almost no slamming. Bearing in mind that my usual cruising speed is only 10 -12 knots I was very pleased with our progress, not only was it more comfortable but it also meant that we were out in it for less time than we expected.
On the way we were passed miles inshore by someone in a flybridge cruiser who must have been doing a good 25 knots - most of the time we could hardly see him for the spray. His hull had to be taking a fair bit of punishment but maybe it was his most comfortable speed.
I think that the lesson to be learned is to experiment and find the most comfortable speed for your boat, it all depends on the direction of the sea and the height of the waves. I started off by hating it but for the last hour ended up enjoying the ride. It was an experience we enjoyed although would not want to repeat it every day!

 

[Guest]

I am beginning to worry because I keep agreeing with you! My not quite late lamented Birchwood has a semi displacement shape which requires to slow up in a big sea but not too much. Below 10 knots and she wallows about. She behaves best when she presents her bow/keel to the waves which tends to cut into the sea. However there have been times with really big seas where you just have to slow down to avoid the feeling that the boat is pounding herself to bits. I have had the props exposed and engines racing in the Irish sea and that is scary! Add to that the fact that wipers can't keep up and the radar can't see any of the buoys we are trying to pick up because the waves are breaking over the flybridge and the buoys are disappearing in the troughs and its time to start doing whatever your religion suggests you should in such circumstances or change your underpants if you are not religious.

However, any time I have been caught in such circumstances the boat has always proved to me that she can take a lot more than the crew!

Nick

ps Boatless on 1 September

 

[Deleted User YDKXO]

Haydn, when I bought my first planing boat the salesman told me the boat's always stronger than the crew so I took him at his word and that's how the flybridge started to come away from the rest of the boat (well it was a Sealine and it was secured with self tappers). I thought crashing through head seas at 20 knots was how it was done and arriving with the contents of the fridge on the floor and a mutinous crew became the norm
Now I'm older and marginally wiser, I've appreciated this ' boat stronger than crew' business is really only bollocks put about by boat salesmen. The fact is that the more you abuse any machinery, the more likely it is to fail.
How big was the sports cruiser that passed you? A 60' Sunseeker can look pretty small in a F7!

 

[hlb]

Re: Agreeing!!

I think we should get married Nick!!
Er indoors never agrees with me.
Most folk seem to have missed the point.
These were overfalls not just rough seas.
Rough seas are easy'ish to find a reasonably confortable route through at fairly fast speeds.
But overfalls just splosh all over the place and are dangerous.
The only thing I can think is by luck or good management he found a better route. Sometimes if you take an inner route you can miss the worst of it.
Once had the experience of makeing 3 knots round Bardsey Island N Wales. The tide was doing 4 or 5 the other way so I'm backing up the rocks!! More power on just did'nt help cos that just meant that the props were in the air doing nothing.
But that was in a 33 with outdrives which slamed in a f2.
Just to prove the point. That cracked every rib in it.
So they do break!!

Haydn

 

[Guest]

Re: Agreeing!!

Remind me never to buy a boat from you - cracked ribs (or were those your own?), demolished gearboxes, blown turbos, oil all over the carpets, exploding holding tanks, tobacco smells (helps with the holding tank problem I suppose). How much do you want for your princess anyway as I am getting desperate?

We once went through Britains largest whirlpool, Corryvrecken, at near slack water just for a look and that was interesting . The boat adopted a mind of her own and did a few pirouettes when we put her in neutral to see what happened. It must be very interesting when the tide is in full flow. Once out into the Firth of Lorne the overfalls are spectacular and, as you say, you just don't know where the next wave is coming from!

I was talking to a yachtie later at Oban and he was saying that the he gets through by applying the slingshot technique - once round the peripherery of the whirlpool and then full power on the way round by which time his speed over the ground is about 10-12knts (but still about 5 through the water) and the boat just gets catapulted out of the whirlpool. Not asomething I would like to try personally. You only go through there at appropriate states of the tide and in a boat with plenty of power.

Nick

 

[Guest]

Getting the size of the boat he spotted wrong is probably the answer. His glasses would be misted up and this would exacerbate the eyesight problems as a result of age and over exposure to the Lamplight club in Bury.

Nick