Springing off

Slow_boat

Slow_boat

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I recently had to spring off a berth that I was being blown onto with wind coming from about a point off the bow. It all went okay with a line from a cockpit sheet winch to a cleat on the pontoon near the bow but it did get me to thinking out the mecanical advantage of various length spring lines and attachment points on the boat and on the pontoon. I came to the conclusion that a line from the stern cleat to a point on the pontoon halfway up the boats length seems about right but I'm not sure if that is theoreticaly correct.

What does the team think?
 
It's not the length of the line - it's the function of making a part of the boat stationary to the fixed object whilst allowing the rest to move.
You could do this with some 4x2 and a few bolts if the HM would let you!
 
Anything more than about 1/3 of the boats length is fine when springing off. A longer line gives no advantage. By choice I prefer to spring the stern out as that enables me to use the rudder to give an extra outward push.

FWIW I use a different technique only available to twin-engined boats, using the engine nearest the pontoon to hold position while the outer one pivots the boat out.
 
Wind forward of beam, get bow out, wind aft of beam get stern out is the plan that usually works. Stern out as SL mentions is generally the easiest.

Twin engine motorboats are great, dont even need the spring line, most will do it on engines only.

Helps if you use plenty of fenders!!!!
 
The advantage a shorter line has is that it's less to haul in as you motor away.

I try to keep it as short as possible, but my hull shape was made for springing off, which is just as well as she can sometimes be interesting to manoeuvre
 
capnsensible said:
Wind forward of beam, get bow out, wind aft of beam get stern out is the plan that usually works. Stern out as SL mentions is generally the easiest.
Click to expand...

Or if there's a significant tide, spring the uptide end off and watch the tide catch the keel.
 
flaming said:
Or if there's a significant tide, spring the uptide end off and watch the tide catch the keel.
Click to expand...

Yup, especially great in rivers. Ferry gliding is great fun too as well as good practice.

Important to watch for back eddies in marinas though, I can remember getting it nearly wrong close to the shore in west Cowes marina. :eek:
 
flaming said:
Or if there's a significant tide, spring the uptide end off and watch the tide catch the keel.
Click to expand...

That's worth bearing in mind before you arrive, having a think about how you will leave.

We were at Shepards in Cowes a few weeks ago, and because we were going to be leaving as tide was flooding, it meant I had to moor going down tide. Which wasn't a problem as our prop walk when I put her stern meant I could get her beam in, put her astern and it pulled the stern in with a bit of a ferry glide astern. We were alongside the pontoon and I thought we'd get a couple of boats rafted alongside.

In the end we didn't, but we did have two 3 boat rafts ahead and astern of us. So we sprung the bow out into the flood tide, ferry glided out of the two lines of boats and away we went.

If I'd approached going up tide, it would have been horrible to get out as the prop walk would have taken the stern off down tide, so I'd have had to use a couple of slips and the whole thing would have got a lot more complicated.
 
Impressive.
There is a reason why there is no decent pic of my boat on this here site: When it goes wrong I would wish to at least try to retain a slight degree of anon !
Cant be much fun being TC etc all the time, I imagine
 
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I have used the technique a few times when departing from a leeward berth.

I have found attaching the spring as far aft as possible seems to give the best leverage, you do need good fenders at the stern where the pressure will come.

An alternative technique shown to me by a fellow club member also works well, especially in a boat with a relatively beamy transom.

The "spring" line is attached to the aft cleat on the side away from the dock, and you motor ahead with the rudder straight or steering the bow in slightly. This causes the bow to steadily swing away from the dock, when you are at an appropriate angle just slip the line. The advantage over the 1st method is that the line is much shorter, and you do not have to switch from astern to ahead which might give the wind time to push the bow to leeward again.
 
I don't really enjoy springing the bow off these days. The main reason is that my boat's stern is fairly wide, like many modern cruisers, and the limited angle I can achieve plus the restriction on tight turning caused by my saildrive arrangement means that the manoeuvre becomes "fail-unsafe". Springing the bow off is more practicable for me and almost always my preference.
 
I recall once springing off by taking the sring round the bow to the offside cleat .This enabled us to make use of all the "sPRING" and end up at right angleto the dock which with the tidal stream enabled the boat to turn round and steam out
 
My most useful fender I have is one like this...
http://www.force4.co.uk/7706/Force-4-Ocean-Bow-Fender.html
It protects the bow when motoring forwards to spring off and can cope with quite a height difference on the pontoon. Because of the way it covers the bow it will fend from when you are starting parallel to when you are at right angles (nnd beyond) to the pontoon. It has always stayed put as well.

The other great thing about this type is that it is solid.. so never any punctures!
 
Another little tip..

When letting the line slip... never use a warp with a spliced loop in the end - It can (and just might) loop itself around the pontoon cleat!
 
Martin_J said:
Another little tip..

When letting the line slip... never use a warp with a spliced loop in the end - It can (and just might) loop itself around the pontoon cleat!
Click to expand...

Tip No. 2. Make sure the crew member releasing the line fully realises that he only has to undo one end of the slipped line and throw it on the pontoon.

Otherwise you get to do it again after going back in to collect your warp.
 
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