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Old 09 September 2002, 11:16   #1
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Getting used to rougher conditions

Hello all,

On Saturday I took my eldest son (6 years), a friend, and his 3 lads (11 year old and 9 year old twins) out in Christchurch Bay, in rather rougher conditions than we've seen before. Did my L2 last year, but having smaller children, mostly have stuck with calmer conditions.

We left Christchurch harbour for the Needles, forecast W/SW F4-5 occ F6 (though it seemed mostly F6 to me!). Despite the large waves, we made good progress, and everyone was happy. Turned left down the Needles Channel to stop for lunch on the beach at Hurst Castle. All the lads had a blast steering the boat on the flat water in the lee of Hurst Spit, then back into the bay, for a rather difficult slog back west to Christchurch.

Hmm. I rather misjudged how difficult it would be making progress into the wind. We spent quite some time just plowing up and down the waves, making very slow progress, and getting very wet, until we got some shelter from the headland, when I was able to get planing, and get lots of throttle practice. With the bow trimmed fully down (is this right in a head sea? Iím not sure, itís my understanding from Dag Pikeís book ďInflatablesĒ), and closing the throttle at the crest of each wave, I was able to make reasonable progress without the boat slamming.

Conclusions:
1. An excellent time was had by all (bright sunshine helped a lot), but I wonít be doing the same with my younger children!
2. 60hp seems like a lot less in big waves than in flat water.
3. I was very glad to have the seating arrangements I haveóall 6 of us on one long jockey seat, with an adult at the back, nice and secure for the kids
4. Not withstanding that, I ought to practice a man overboard drill in such conditions
5. What a brilliant little boat my Ribcraft 4.8 is.

One question: is such slow progress what I should expect in such conditions, or was there something better I could have done?

Second question: Iíve got all the kids in 100N foam buoyancy life jackets (Crewsaver Spiral), but am not totally convinced. Would anyone recommend junior size auto gas inflation life jackets for kids?

cheers,
Simon
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Old 09 September 2002, 13:12   #2
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Simon, Can't help with lifejackets but you seem to have proved the point that it is always more uncomfortable (and slower) heading into a sea than running before it! I'm sure you know this but its because heading into a sea you are into the steeper face of the wave whereas running before it you are on the long slope.
Mind you the same rule seems to apply in yots as well in my experience!

I have Dag Pikes book as well and have attempted to practise the theory with some degree of success. For me driving a RIB in rough conditions is more of an intuitive thing - perhaps as a result of experience gained etc.

You have also proved admirably the point about decent - I mean Jockey - seating. Too many RIBS out there with nasty bench seats - you would not have had such an exhilirating time and your spine would be somewhat sore! Its also a truism that its fun when its sunny but a rain-squall can put a completely different perspective on things!

I have never driven a ribcraft 4.8m in the rough but I have followed one round Britain in a support RIB and as a number of happy owners here will confirm, believe them to be the finest RIB of their size!

Cheers,
Alan
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Old 09 September 2002, 13:36   #3
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Comments re Ribtec

Being a total novice I can add nothing to help I am afraid but thanks for such an endorsement of Ribtec 4.8m. By coincidence I had just posted a thread on subject of Ribtec.

Actually one thing does come to mind re rough waters. Wavehumper put me on to a site which I am sure you have seen and has articles on boat handling in rough waters which I have read and felt was good.(All I need now is a boat!!!)

I will pm you as I can't remember site name off hand.

Cheers

Clive
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Old 09 September 2002, 14:38   #4
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hi simon
not like the weather when we met on studland beach eh?
You have got it right-trim up when you are going with the waves so that you dont drop of the crest and down the hole in front of the wave with a bow down attitude so that you stuff into the back of the next wave.
Trim down when you are going into the waves so that you dont fly skywards off each roller as it marches towards you.
But everything is relative and is probably not fully up or down - rather an adjustment to what your normal trim angle would be. As has been said , more intuitive than dogmatic up or down, whilst remembering the basic principles.
trouble is you get the kids hooked on this ribbing thing and before you know it they'll be leaving you notes for when you get home from work to say they have borrowed your boat
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Old 09 September 2002, 14:59   #5
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Hi Simon

Had a similar day off Milford Haven a few weeks ago, big swell, 2-3 meters and a few big overfalls where the waves broke. I decided not to take the kids as it was 30 miles trip each way and if they didnt like it there was no turning back.

Was interested what sort of speed to managed. I found that a max of 12 to 14Kts was good, still on the plane but not to much for the wave crests. I also found working the throttle quite hard work, and only changed setting when the next wave didnt look right.

This was quite a supprise as I had always planned for passages at about 20Kts, just shows how wrong i was !

Regards Gary
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Old 09 September 2002, 15:27   #6
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Simon

You picked an interesting piece of water to try in the rough.

With such a young crew you made the correct decision to throttle off. In rough seas Iím always changing the trim, throttle, tabs, angle of attack to the waves etc just in case there is a better way, most times there isnít, but Iím always learning.

The MOB drill is worth practicing along with insuring that your crew know where the spare kill-cord and engine key are in case youíre the one that falls out !

Regards

Mark
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Old 09 September 2002, 15:37   #7
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Ribtec / Ribcraft ????

different boats arent they, although both appear to have excellent reputation.

I've been out in the Solent in a 21 foot bayliner I once owned, even in a 3/4 he size of waves used to put the fear of god in me !

Came back over from Cowes once in a 17 foot speedboat once when the wind got up a bit, had to do exactly the same basicly plod back because of size of waves, at least with a rib you have the piece of mind that you dont have to worry about it getting swamped, with a speedboat it would just sink !
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Old 09 September 2002, 17:02   #8
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working the thottles etc is a pointer to the safety issue of fuel when it gets rough. We had a terrible job here about 12 years ago when some local boat anglers (fast planing boats) came down the coast about 10 miles on a flat calmwinters day but with gale force winds forecast. The wind got up as promised (and eventually even stronger) and they were faced with a 10 mile return trip. They used next to no fuel on the outward trip, but soon ran out on the return as they climbed up the waves and then dropped down into the next trough time after time.
The inshore lifeboat went out in conditions beyond its spec on what became a medal award service, plus helicopter etc etc. Several rescued but two or three fatalities. So basically there ain't no miles per gallon at sea and when it gets rough the fuel goes down at an alarming rate.
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Old 09 September 2002, 17:11   #9
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Testing but fun isn't it

If you wanted to get some better rough water training, you could ring Paul Glatzel in Poole. or IRS in Lymington.

Paul Glatzel wrote an article in this site called rough weather handling

IRS who are all ex Marine coxwains can be found at www.intrib.co.uk

I also guess there is no end of experience in the contributors to this site.

Britt (Mrs. Thewavehumper)
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Old 10 September 2002, 03:17   #10
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Good point from Gary ab out speeds and expectations of boat speed in the rough. We may all plan on passages o 20-25-30kts etc but invariably you will get slowed down, particularly in a headsea, and you will burn much more fuel. I can concur with the 12-14 kts for a Ribcraft 4.8m in such conditions having followed Spirit (RB4 rib) from Dungness to Solent at 12kts! (At which speed the RIB I was in - 9.5m was going THROUGH the waves, a very wet experience!)

Its all relative to size though - my BWM DS21 was more comfortable at 20kts than 14 in those conditions whereas the 7.5 Scorpion goes better at 30!

Matiboy, I've had loads of fun going out in convoy with friends in Fletchers/Glastrons etc who scream around at high speeds in dead calm conditions but once it gets a little rough just can't keep up!

Alan
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Old 10 September 2002, 05:23   #11
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Quote:
Originally posted by wavelength
hi simon
trouble is you get the kids hooked on this ribbing thing and before you know it they'll be leaving you notes for when you get home from work to say they have borrowed your boat
Hi Dave, hoping this won't apply for a few more years!

On speed, I currently have no way of measuring this, so when the kids are always wanting to know how fast we're going, I have to guess. Gary, is 12 knots minimum planing speed for you? I've guessed my top displacement speed is about 5 knots (haven't measured my waterline length ...), but I reckoned my minimum planing speed was somewhat more than 12 knots.

Working the throttle was hard work, but made a huge difference in comfort. Fuel is a concern. My fuel gauge is just a bunch of 8 LEDs, and I'm in the process of trying to calibrate it. I don't think it's terribly accurate - perhaps due to the shape of the fuel tank (triangular cross section under the deck). I generally fill right up (60 litres) before going anywhere.

cheers,
Simon
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Old 10 September 2002, 06:41   #12
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Quote:
On speed, I currently have no way of measuring this
Hi Simon

What you need is a hand held gps. Great fun. A superb safety item. Good for back up if you get a gps fitted. I can recommend the Garmin 12 at about £130.00

Keith (value for money) Hart
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Old 10 September 2002, 06:47   #13
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Hello Simon. ref your query about lifejackets. I carry two autogas, two manual gas and two crewsaver foam buoyancy. I always put kids in the foam buoyancy jackets. Gas inflated jackets are fail dangerous and they have been known to fail because of lack of maintenance. usually the cylinder seal corrodes away. If the kid was to go in the oggin, would he/she have the nous or the breath after going into cold water, to inflate the jacket through the tube. Would an adult for that matter. Personally, I wear an autogas for the comfort factor but all the jackets are checked regularly. Others will have their own preferences but I hope this helps.
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Old 10 September 2002, 11:36   #14
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Interesting comments about life jackets / bouyency aids.

I have always worn a foam style bouyency aid (from dinghy sailing) but further to having an RNLI SEA-check (great idea, friendly chat really) the guy suggested wearing auto-gas life jackets - so i do!

I bought two 'coz there is normally only two of us when up to anything serious - obviously i use the conventional bouyency aid for skiing and similar wet activities, but his theory was that falling out at speed (and maybe night) you want the lifejacket to keep you afload, head and mouth out of water - hence the auto gas choice.

How long should i think about before i replace / service it - would i know if cylinder seals have corroded through a regular check???

Comments invited!
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Old 10 September 2002, 15:43   #15
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Hi Simon, 12kts was with one up, just me. If you had more people in hence weight it will go up but i start planing just below 12kts on the GPS.

Regards Gary
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Old 10 September 2002, 16:02   #16
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Hi Simon,

I thought it was about time I put in my twopennyworth as I have the same craft as you albeit with a Mariner 60 2-stroke lump which, I think is lighter than yours. I also have an A-frame which may take the rear end weight near to yours

As regards speed, I use GPS as the speedo fitted dosen't work below 10kts, is inaccurate and reads in MPH. I reckon that my max. displacement speed is 6kts, (I have found that, at low speeds, a crewman in the bow increases the speed by up to 1knt without touching the throttle). Minimum planning speed is 11kts and maximum WOT speed is 32kts (on a flat calm sea) with two adults up. The revs for the last figure is 4800 but, as the engine should go up to 5500. I think I need to reduce the pitch on the prop. I have found that with a head sea of about 1m the most comfortable speed is around 14kts, anything above and we're airborne, anything much below and we're off the plane. The worst conditions are beam seas then the speed can vary between 12 & 16kts depending on how we take them but the intense concentration required can be very tiring. Even on a short trip from Bembridge to Chichester Harbour recently in these conditions I was exhausted after only 30mins - perhaps I'm too old for these RIBS!!!

I have auto lifejackets for everyone - I also unpack them after every trip to wash off and check the cylinders/firing mechanisms. I also have a spare killcord on board and everyone knows where it is and how to use it.

The Ribcraft LED fuel gauges are "interesting" to say the least - when mine has the 2 reds showing I need 50L to fill to the brim. One other tip with these - if you do any night running, stick a bit of duck tape over the gauge or you will be blinded!

Keith (King Bracket) Hart is right about the H/H GPS but trying to read it at speed in a bouncy sea is almost impossible - its hard enough with a fixed unit.
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Old 12 September 2002, 13:42   #17
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Hi Simon,

After read a thread here (some months ago), I decided to purchase the Crewsaver "Air Foam Lifejacket".

They are 150N lifejackets, partial inflatable - oral, not automatic, is always buoyant (due to cell foam). Of course 150N will only apply full inflated.

see
http://www.crewsaver.co.uk/leisure/airfoam/main.htm


bye
pedro
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Old 12 September 2002, 15:32   #18
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Quote:
Originally posted by Viking
Testing but fun isn't it
Apologies Wavelength, this reply was meant for the opening part of the thread. I am emabarrassed about saying this immediately after you explained how three boaters died on the water
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