RIB's as "Tugs"

limeydal · 28 October 2006, 17:39

Have a little problem down here and wondered if anyones has experience or "opinion" on how best to do this

Have to get the "Surprise" safely away from the dock and into the Bay ready to set sail.
Immediately to the Stern we have a WWII sub and off the starboard bow,the "Star of India".
The museum has a PIlot boat that is going to attach a line and I wondered if I could get round and "Push the bow with my RIB.
Had seen this done to assist docking with another tall ship and wondered how much"Push "I can get with my mere 90HP and what effect we could expect

Any ideas of how best to get her out??
She does have an engine but limited manouvering capability
cheers Dal

Limey Linda · 28 October 2006, 17:59

Hi There
Sounds like a fun project. Needless to say the better the tide/wind conditions the easier it will be; a mild offshore wind would be ideal. Suggest pulling the bow out while swinging on a still attached stern line. No power on vessel. Release the stern line when bow is clear and engage vessel power when bow is pointed to clear water. Make sure dockside aft quarter is well fendered. If you need to nudge with your Rib then your 90 HP will be ample, just take it slow and make sure you have good radio contact with all concerned.
Hope this helps.

PS. As per Cods advice below, don't get squished.

codprawn · 28 October 2006, 18:04

A RIB would be fine as a bow thruster BUT there is no way you should be in a position where you could get squashed between the ship and the dock - you don't want to end up as a fender!!! It would be safer to tow the bow out I think.

So much depends on wind and current. Remember 1 horse can pull a 100 ton canal barge no problem once it starts moving. Stopping it is another matter.....

limeydal · 28 October 2006, 18:34

My buddy onboard seems to think they can tow out the stern and try and use her engines to reverse her out. Would have to move pretty well paralel to the dock as the sub lies only a few feet behind

So tied off and well fender the dockside bow and "spring her out that way

Will have the camera ready either way

cheers Dal

marknj · 28 October 2006, 19:13

Surely if the skipper is not sure how to go about this then he should not be in charge of such a vessel?
It is a simple manoveure, as long as the weather is ok. With the pilot boat and a 90hp rib should be easy!

Pete7 · 28 October 2006, 19:35

The Royal Navy (before we sold it to Canada) did an experiment with two inflatables and a submarine. It took 24 hours for the two inflatables powered by 40 hp outboards to turn the sub round.

I think you risk damaging the tubes if you try and push but towing out could work. What you really want though is a rib with a large diesel turning a big prop to generate lots of thrust

Pete

Channelwatch · 28 October 2006, 23:46

Hey Dal,

Still waiting for that visit. How about putting a line from the stern to the pilot boat and a line from the bow to your RIB and slowly pull her sideways. That way you don't have to push against the dock and Surprise can use her engine to control fore and aft movement. As someone said earlier, it should be a simple move and we do it all the time with just one boat and no power on the vessel being moved. Have fun and come up for a visit.

tim griffin · 29 October 2006, 07:40

Seen pictures of how in the old day's they would lay a kedge anchor and pull the boat out on this . Either fore or aft depending on which way they wanted to exit.Could lay a bow and stern kedge and pull her out sideways until enough sea room .Same as using the Pilot boat and pulling her out sideways

BogMonster · 29 October 2006, 09:18

With no tugs in our part of the world the local launches are routinely used to assist docking etc of sometimes fair sized boats. Not sure what that thing you are looking at weighs, but probably a lot less than some of the fishing vessels etc. The bigger of the two launches run by our company has about 500hp on tap I think, so if 500 hp would push/tow 5000 tons I'd imagine 100 would push/tow 1000 tons with a similar degree of effectiveness. The big factor will be the wind, choose a calm day or one where the wind is blowing the way you want it to!

As it happens yesterday I watched somebody leaving the jetty here in a yacht (fairly confined space) and he appeared to be using only mooring lines and sail power. I didn't see it all but basically it looked like he let it drift out from the pontoon controlling the position on long lines till it was facing the right sort of direction, then raised a sail, released the lines and off he went. It was quite cool given that most of the wimps driving yachts these days need to use an engine when they are within five miles of land, he evidently knew what he was doing, always good to see things being done the way they used to be before people had engines and radars and stuff

Matt · 29 October 2006, 10:11

Put a kedge anchor off the stern, also pulling slight forwards, to pull the stern away from the dock. Keep the bow line & a bow spring spring on to stop the kedge pulling the boat forward, and the kedge'll stop it moving back.
Nice and slow, and the ship is secured all the time.

limeydal · 29 October 2006, 15:54

Marknj,
think the Captain knows what he's doing

He helms the "California" twice a week and has out manouvered and run rings around all- comers in the Cannon battles we have.
Problem is the "Surprise" was bought as a static exhibit and squeezed in as the photo below shows. It is after a year or so of re-fitting to the USCG standards that they are going to take her out for the first time.
So,many thanks for all the interesting ideas and will let you know how it goes,
cheers Dal

Alex Brown · 29 October 2006, 23:35

Little inflatables are used very regularly by tallships to assist with berthing and unberthing.

However, most don't have rigid hulls, and therefore wouldn't be risking a parting of tube and hull right at the bow with the pushing. Those that do have rigid hulls though seem to have large tyres strapped around the bow to spread the load....

When it came in this summer, I used our small dory at work with a 40hp engine to assist with the berthing of Dunbrody at the dock.

With the correct positioning, a small boat can handle a much bigger boat without a problem at all..... what you will find though is that if you are pulling the boat away from the wall, you will need to be a bit of a distance away from the vessel or your own wash will be just pushing against the hull of the boat you are trying to move, which is why it'd be far better to push.
The other week in a gale, we had to pull a large ketch just a little bit smaller than the one you're looking to move away from a wall at the top end of the dock.... the dory tried with no success, and even when I had the tug attached, I was nearly at full weight (about 3.5ton pull) before the boat started to come in my direction.

To be honest though, I wouldn't use the rib in that situation cos you "could" cause damage to it - it may be better to see if there's a small harbour launch around to assist the boat with coming away from the wall. If you're not sure, it's always best to ask for more help

-Alex

limeydal · 30 October 2006, 02:20

Alex,
many thanks! Great to have someone experienced who has done this

We have the Museums pilot boat to do most of the "grunt work".
The RIB idea was to give her bow a gentle nudge if she was offcourse.
The rubbing strake on the XS is pretty hefty ,but I take your point on the possible damage.
Luckily we are in sheltered waters with usually the wind being weak and blowing from stern to bow.
cheers Dal

Cookee · 31 October 2006, 09:14

We have used RIBs for this purpose a number of times when positioning boats for a movie - 90hp will be plenty - just beware of overdoing it and make sure you can comunicate with the skipper at all times - he is the one in charge and don't rely on just making a plan before hand - things change very quickly!