Following sea

paul1 · 17 April 2006, 19:59

Hi, Does anyone have any advice with regard to powering through a following sea, i have read the 2 short stories from the Power boat trainer, and was quite surprised today at the speed and freqency of the waves coming from behind , Whats the safest way to ride this situation, fast and hoping between waves,? or somewhere between riding to the back of the crest, or simply going slow?.
I find driving into the wind and waves fine , but feel vunerable with a following sea on the way back, any experiences to share.?

Biggles · 17 April 2006, 20:43

Quote:

Originally Posted by paul1

Hi, Does anyone have any advice with regard to powering through a following sea, i have read the 2 short stories from the Power boat trainer, and was quite surprised today at the speed and freqency of the waves coming from behind , Whats the safest way to ride this situation, fast and hoping between waves,? or somewhere between riding to the back of the crest, or simply going slow?.
I find driving into the wind and waves fine , but feel vunerable with a following sea on the way back, any experiences to share.?

Hi,

I must admit I don't really see following seas as a major problem as long as you keep going. Possibly I haven't got the experience to see the problem.
What I do if its a big following sea is work the throttle. I find that I will be travelling a lot slower than normal because my greatest worry is going too fast off the top of the wave and stuffing my nose in the back of the one in front.
We had these conditions in the Solent coming back from yarmouth today and for a 4 meter boat some of the rough water seemed quite large in the area of the IOW ledges. I found that I was travelling slow and weaving through the waves where I could see less active water. it took ages and a couple of times I noticed that the boat would really struggle to get up the back of the wave from a slow start.
Being a small boat owner I find the in your face waves the hardest to ride and they also give the most uncomfortable ride.

Pete7 · 17 April 2006, 20:54

Paul, in a lightly loaded rib with everything secure it can be quite exilerating driving down the waves. However its takes concentration and a regular change of driver helps if you have to travel any distance. Your at a slight disadvantage with those Mariners if they don't have power trim and tilt as it helps keeping the bow up when going down the waves. In the Solent, the chop is often to short to do anything with it, but further offshore or wind with tide its often possible to use the throttle with bottle to drive over the waves. One problem is it is very easy to end up going faster than you want. So use the back of the waves to slow your speed dipping the trottle as you go over the top keeps the bow in contact with the wave and then power on going down the wave to keep the bow up to avoid stuffing into the back of the next wave. However you will get the odd wave completely wrong which will result in clouds of spray and soak all on board. Take care when entering harbours though, chi and Landstone to name too if there is a big rolling waves. If you are travelling at slow speeds the wave will over take you and cause a broach. Sitting on the back of such a wave would be a good move.

Final thought how about doing an advanced powerboat course.

Quote:

Originally Posted by paul1

I have read the 2 short stories from the Power boat trainer,

What was this btw ?

Pete

BogMonster · 17 April 2006, 21:19

Well I am a newbie and just "feeling my way" in this so I probably should stay shut up, but what I have discovered so far, in a force 5 or so (not uncommon here, prob about that yesterday) is that going slightly faster than the speed at which the wave front is travelling is pretty good, in my boat this gives a comfortable ride and is very relaxing. Trying to go too fast I found to be really rough.

Going back in to it is a different proposition there seem to be 3 options: go slowly and get very very wet (waves break and come over the bow), go a bit quicker and get a rough ride as it crashes down on to every wave front, or go like a bat out of hell which gives the best ride right up until a big one arrives and then it really really hurts .... I had sore B&&&&&ks from the jockey seat after an hour or so of that yesterday!

Nos4r2 · 17 April 2006, 22:35

Quote:

Originally Posted by paul1

, fast and hopping between waves,?

Johnny Fuller posted a vid of what happens when your stern gets flipped up in the air by a wave-far more likely to happen in a following sea...

http://media.boatmad.com/gallery/v/m...stuff.wmv.html

Having stuffed my sr4 at 20 knots trying to go too fast in a following sea I'm not in a great hurry to do it again. If we'd been in a hardboat there would have been search parties out for us.

Jono · 18 April 2006, 08:20

Quote:

Originally Posted by Nos4r2

...... If we'd been in a hardboat there would have been search parties out for us.

Interesting observation.......What makes you think that?

havener · 18 April 2006, 09:38

Quote:

Originally Posted by Nos4r2
...... If we'd been in a hardboat there would have been search parties out for us.

Personally, I'd tend to agree.

Main reasons -

The shock loading absorbing qualities of a rib shouldn't be underestimated. In a typical "stuffing" the tubes will take a lot of energy out of the impact, disipating it along the length of the rib. The boat is then better equipped to follow it's natural bouyancy trend, i.e. to lift the bow and therefore pull out of the curve.

Most ribs tend to have better aft drainage than harder craft, so the water is able to leave the craft quicker, and in any case water moving to stern transfers weight which again helps lift the bow.

Of course, the best solution is to do what the RNLI do on the Atlantic 75s and simply have no stern!! A following wave then simply enters the craft, disipates and exits.

A lot of people seem worried about following seas, but really the biggest danger to a rib is high waves going bow on - just look at the "RNLI Get Wet" clip on the same site linked earlier in this thread.

I also assume by "hard boat" Nos4r2 meant dories, etc...for bigger craft, having driven both pilot boats and Tyne class lifeboat in following seas, I can assure you getting pushed from behind by a wave has little effect whatsoever...unless you're in one hell of a storm.

My personal advice for following seas in a rib would be (a) no-one forward of the driver (keep the weight back), (b) make sure all elephant's trunks and drains are down and clear, and (c) NEVER get scared and try to turn unless the wave length is at least twice that of your boat.

Simon

Jimbob · 18 April 2006, 12:20

The boots tell a reasonable story, but experience is the only way for me

1) Trim up a little
2) Sit on the back of the wave and watch behind so that a waves does not come over the transom, or help you broach
3) miss the breaking areas if you can
4) Accelerate to the next

We has a following sea coming into Chichester and follwed these rules, no problem, but it was a F5/6 and was careful as there is a bar that can make it worse, however there were a couple of times the nose was up

on a hardbost (we could not keep up with the speed of the waves) going into Poole the transom was pushed forward by the waves causing the nose into the water, again a bit of practise and you get used to streeting to prevent a broach

Nos4r2 · 18 April 2006, 18:04

Quote:

Originally Posted by Jono

Interesting observation.......What makes you think that?

The angle we stuffed at, the amount of water we shipped and we were being pulled towards Shambles bank by the spring tide at the time.

If we'd been in a hardboat the bow would have gone under as far as the cockpit.

Yes, I meant dories, speedboats etc.

gtflash · 18 April 2006, 21:04

Thios could turn into the hard boat blow up boat thing or we could even steer it into another hard nose soft nose rib debate!!! wind em up boys

Quote:

Originally Posted by Nos4r2

The angle we stuffed at, the amount of water we shipped and we were being pulled towards Shambles bank by the spring tide at the time.

If we'd been in a hardboat the bow would have gone under as far as the cockpit.

Yes, I meant dories, speedboats etc.

Nos4r2 · 18 April 2006, 22:07

Quote:

Originally Posted by gtflash

Thios could turn into the hard boat blow up boat thing or we could even steer it into another hard nose soft nose rib debate!!! wind em up boys

Nah, just saying I'll take my rib into conditions I wouldn't take a hardboat into-and I'll go faster than I would in a hardboat in similar conditions. Horses for courses-if I wanted to stay out for a weekend I'd buy another 17-19' cabin cruiser or the like.

I had a dory, a microplus and a speedboat before the SR4 and I'd far rather be out in the SR4 when it gets shitty-even though the others were substantially bigger.

Cookee · 19 April 2006, 09:04

Quote:

Originally Posted by Nos4r2

Johnny Fuller posted a vid of what happens when your stern gets flipped up in the air by a wave-far more likely to happen in a following sea...

http://media.boatmad.com/gallery/v/m...stuff.wmv.html

Having stuffed my sr4 at 20 knots trying to go too fast in a following sea I'm not in a great hurry to do it again. If we'd been in a hardboat there would have been search parties out for us.

Just for the record (and I was there navigating in a Phantom 18 in the same race) whaty happened in that clip had nothing at all to do with a following sea, I have been there and got the very wet T shirt on a seperate occasion, and it is speed that does that, and it doesn't matter which way you're going.

A stuff that one would experience in leisure boating is much more influenced by the direction of the waves and the shape of them, unfortunately because of the different wave lengths and boat lengths, there is (IMHO) no magic solution for avoiding this as every situation is totally unique, you can only apply general rules and learn from experience!

Rob Mcarthy and my navigator Graham Lawton were racing a Bernico around the IOW a few years ago and despite deciding they didn't want to go on, the Needles was that nasty - turning around and returning to Cowes downwind was worse than going all the way round!