Lowest speed under engine

[snowleopard]

cat with 1 engine & 2 rudders. sounds like the nightmare scenario. even worse than one i met a while back - twin engines and centreline rudder - at least he could steer with his engines! the principle of number of props = number of rudders should be burned onto every designers brain. it may be heavy and expensive but i can tell you that 2 props & 2 rudders, 17 ft apart, make it harder (but not impossible) to make a prat of yourself!

incidentally i did say 'as fast as necessary' it's the people who show off by doing it at a charge that i'm getting at. control linkage failure does happen, more often than you'd expect!

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[Talbot]

I can move the outboard through about +/- 20 degrees independently of the rudders, which does help, and makes low wind manoeuvres easy. but high wind can be a tad interesting, especially as I have a tight 120 degree turn to get into my berth! turning to port and berthing portside to. Wind off the berth is a real b*stard

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[snowleopard]

wouldn't it be nice if marinas had big windbreaks all round? i have the interesting dimension of drive from the mast. before attempting any berthing operation i have to set the mast angle to prevent it taking charge, that usually means locking it at 90 degrees. if i have a big crew i can use it as an air rudder. on the odd occasions i have forgotten to set it, the results have been straight out of the Art of Coarse Sailing.

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[oldharry]

3.5kts sounds to me quite a lot faster than is necessary or desireable except for a very heavy long keeler. If the engine is ticking over at around the corrct revs then it may have too large a propellor providing too much thrust at low speeds (and conversely not allowing the engine to develop its full power at high throttle settings.

Undesireable because several tons of boat moving at that speed takes some stopping, and close quarters manevering as you found becames rather hair raising. That is quite fast enough to do substantial damage if anything gets in the way.

The optimum lowest engine speed is that at which in calm conditions the boat is still responding positively to her helm, which could be reasonably expected to be no more than 1 - 1.5knots with most modern designs.

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[geoffatstanpit]

Wow! Am I glad I have a swinging mooring with no tide - all I have to do is approach slowly, walk forward, pick up the bouy, drop the riser over the cleat and it's done.

The previous owner of the boat changed the 2-stroke OB in the well for a 4-stroke because he couldn't get into his marina slow enough without it stopping.

I do have to get into a marina berth a couple of times a year but I find that if I shout loud enough and panic a bit all sorts of people pop out and take my lines.

Geoff

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[walker]

Like the sound of that approach!

The actual manouevering is not so much a problem as speed can be controlled by short bursts and she carries her way quite well for (will I invoke the scorn of sailorman again if I get above my station and describe her as) an AWB - I take the 'slow is pro' philosophy to ridiculous extremes to the point where marina staff have gone off too moor up another boat while I weigh my options! But I want always to be able to do it myself if I have to. Seems that my tickover speed may or may not be normal but it migth be worth getting the yard to check it out over the winter.

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[nealeb]

I am a little surprised that you need a spring line to hold the boat when leaving the berth - mine doesn't go anywhere fast and I have enough time to drop lines and climb back on board. Trick is to make sure that the line that is doing all the work is the last one you drop. You can always tell which one it is - it's the one on top of the cleat that has to be moved to release the others! My berth is reasonably sheltered, though, and the boat does have a fair bit of inertia to overcome...

For coming alongside single-handed (28' long-keeler, around 8.5ton) I use a 10mm nylon line with a big loop in the end held open with a length of hosepipe. It goes through a midships fairlead and back to an aft cleat to get plenty of length and will absorb quite a lot of momentum due to the springiness. Then the helm lashed over against forward gear trick to hold her in place. The line seems pretty flimsy compared to the "proper" mooring lines but is surprisingly strong in this role and needs to be on the light side to get the springiness.

I can coast 50yds or so depending on wind from knocking into neutral, and probably only doing around 1.5-2kt at tickover before that. Just before she came out of the water I realised that the revs were rising when I went into gear so I gave the throttle cable adjuster a little tweak to increase the play around neutral just to make sure that the engine is still at tickover when going into gear.

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[Guest]

Bav NOT a AWB ........... since when ????? What is it then a CLASSIC ???????

<hr width=100% size=1>Cheers Nigel ..... <A target="_blank" HREF=http://www.geocities.com/solentlifeuk/>http://www.geocities.com/solentlifeuk/</A>

 

[Guest]

works on ships an\'all ....

size is only relative and only matters really when momentum is involved.

same trick can be used in reverse to leave berth.

<hr width=100% size=1>Cheers Nigel ..... <A target="_blank" HREF=http://www.geocities.com/solentlifeuk/>http://www.geocities.com/solentlifeuk/</A>

 

[Guest]

i think it should be ....

pass line round midships cleat and inboard end back to winch. outboard end is then ready to drop over suitable shore bollard / cleat. the inboard end can then be lengthened / shortened as required to have boat sit right ready for other lines.

with the permanent berth for my boat - all lines are left on pontoon ready for return .... set to length. i then use a line set-up on boat to come alongside .... set at midships. drop over, have boat sit alongside, hop over pick up permanent lines and drop onto respective cleats on board. then first line used when coming alongside is taken off....... and stowed neatly.
why do i do this ? my lass fell in doing a bow-line and now thoroughly dis-likes average marina pontoon fingers as unstable tippable areas waiting for the unwary !!!

<hr width=100% size=1>Cheers Nigel ..... <A target="_blank" HREF=http://www.geocities.com/solentlifeuk/>http://www.geocities.com/solentlifeuk/</A>

 

[oldharry]

< if I shout loud enough and panic a bit all sorts of people pop out and take my lines.>

... a most seamanlike solution, Geoff. One probably most of us have had to resort to at one time or another!

But perhaps not to be relied on if your boat lives in a marina berth.

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[walker]

The question was really about mooring up, not leaving. I do though tend to motor against a spring fairly routinely for leaving a berth where I being blown on - Stella P has an awful lot of windage and its just so much easier to get the bow/stern pointing the way I want to go by doing so.

I'll have to try your hint about tweaking the throttle cable to see if I can get the tickover speed down a bit.

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[walker]

I rather suspect that Mr sailorman was suggesting that a Bav is sub even an AWB, perhaps just to spice things up, there not having been a Bav bashing session recently. Frankly (and of course ever so humbly), I can't be a***d.

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[walker]

Re: i think it should be ....

By jove, I think I've got! Thanks Nigel.

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