Ferry Gliding

[RIN]

Following Spottydog's post a few weeks ago in which ferry gliding on the Hamble was discussed, we had our first go at it in a tight spot. The hardest part was just turning the boat around whilst the Ebb was going (we have to go up around the top of the pontoon and come back downstream to get to our berth Need to have plenty of way on the boat to do this.

Having done that, getting back up to the berth and keeping in position was ok (if rather more exciting than I was expecting) what I found difficult to control was the speed we shot across the river whilst gliding resulting in a perfectly square arrival on the pontoon, but much heavier than I would have wished.

Any tips for managing this? 30ft boat with twin 290DP's

 

[Whitelighter]

The trick to any slow speed manouvering is to work out how to use the forces already acting on the boat, rather than fighting them.

As you suggest, turning around is not so easy and increases the risk of something going wrong and, because of the speed to have to use, means that it will be a harder bang if it does.

What I would have tried is, rather than turning reverse usung the ebb to push you back. Your forward gear then becomes your break (you dont need to use reverse as you shouldnt power in the same direction as the prevailing current). You can use you two engines to maintain steering using forward tick over on either engine. Then as you draw next to your berth, gently ferry glide across.

By turning round and approaching forwards you are exposing the boat to an uneccessary turn and therefor making the move more complicated than it needs to be.

Spent all day teaching this techinique at Port Hamble last Saturday and its great when it works.

 

[Searush]

OK, so I'm only a stupid Raggie, but 2 engines & turning is difficult?

Now I only have one engine, but I spent many years travelling on the Mersey ferries (very strong tides & exposed berth) & watched them come alongside ferry gliding & not crack an egg. I have also seen them forward port, astern starboard & spin away on their own keel length, or spin turn to approach bow to current. Think about the wind & current & how they will affect your hull, use those forces to help you turn. ie, my bow tends to blow off, so I use a hard burst of throttle with full rudder (using propwash) to spin the boat through the eye of the wind, the wind then helps me round. If I am gentle trying to turn, she will blow off the wind & won't turn.

I frequently ferry glide on the Conway (more strong currents) and the Menai Strait for approaching berths or moorings. Always best to go head to current, unless you can steer accurately astern. The point is to balance your speed against the current & use the angle of the boat to the current for sideways motion. If travelling too fast sideways, simply straighten into the current, use the throttles to balance your speed. Practice, practice & practice, it will become simple in due course.

 

[Whitelighter]

You are quite right Searush, though with this type of boat there are a few things that change the operation slightly.

Firstly, with outdrives you have no rudders, so now power = no turning. Its not like a yacht with a huge gurt thing hanging under the back. Secondly, unlike your boat there is very little below the water line, so much so the front 30% of the boat is not really gripping the water, making the bows very suseptable to windage.

You are right that using opposing engines can turn a boat in its length, but with the vectored thrust of sterndives using the wheel and throttle is more efficicient (as it is with shafts, but here there is no rudder for prop wash to work with).

I can understand the OPs issues with turning at the top of the hamble, but as I have already described it isnt necessary and berthing can be done USING the prevailing forces rather than FIGHTING them - as you correctly suggest.

 

[RIN]

OK, so I'm only a stupid Raggie, but 2 engines & turning is difficult?

Now I only have one engine, but I spent many years travelling on the Mersey ferries (very strong tides & exposed berth) & watched them come alongside ferry gliding & not crack an egg. I have also seen them forward port, astern starboard & spin away on their own keel length, or spin turn to approach bow to current. Think about the wind & current & how they will affect your hull, use those forces to help you turn. ie, my bow tends to blow off, so I use a hard burst of throttle with full rudder (using propwash) to spin the boat through the eye of the wind, the wind then helps me round. If I am gentle trying to turn, she will blow off the wind & won't turn.

I frequently ferry glide on the Conway (more strong currents) and the Menai Strait for approaching berths or moorings. Always best to go head to current, unless you can steer accurately astern. The point is to balance your speed against the current & use the angle of the boat to the current for sideways motion. If travelling too fast sideways, simply straighten into the current, use the throttles to balance your speed. Practice, practice & practice, it will become simple in due course.

Well where I used to berth there was very little current so it was tickover only with one hand holding a gin and tonic

Usual turning technique is to have one engine ahead, one in reverse and the boat turns on the spot. however, with the ebb and the wind blowing in the same direction, it would not turn (no bow thruster) and after doing this for 30 yards or so I ended up powering to put some way on the boat and turning back into the current/wind on the stbd (downstream) engine. There is a "U" shaped pontoon arrangement a further 20 yards downstream that I definitely did not want to visit.

I expect you are right though, it will require a bit of practice, and I think I will avoid coming back at the hight of the ebb

 

[benjenbav]

where I used to berth there was very little current so it was tickover only with one hand holding a gin and tonic

You probably need to switch to vodka martinis, then they will be nicely shaken and not stirred by the time you dock.

 

[Peanuts]

"we shot across the river whilst gliding resulting in a perfectly square arrival on the pontoon, but much heavier than I would have wished."

So what are we saying Richard, it was more of a landing than a mooring?

 

[RIN]

"we shot across the river whilst gliding resulting in a perfectly square arrival on the pontoon, but much heavier than I would have wished."

So what are we saying Richard, it was more of a landing than a mooring?

It surprised me just how quickly it is possible to move sideways across the river - After all, you'd think the amount of hull in the water would act as a brake! It was a bit of a thump but the fenders coped manfully with it. Will be popping down for round 2 this week.

And anyway getting back on your berth without damaging your boat (or anyone else's) is always a succesful mooring in my book!

 

[Philiz]

Any tips for managing this? 30ft boat with twin 290DP's

Practice, practice, practice. Very satisfying when it works well though, or so they tell me

 

[Searush]

Rin
If you are moving sideways too fast, you are at too great an angle to the current. It is the current that moves you sideways & the amount of sideways depends on the speed of the current & your angle to it. Simply straighten up a bit. If you are heading directly into the current you will not move sideways at all, just a little forward or back depending on your speed relevant to the current.

 

[Jonmendez]

Rin
If you are moving sideways too fast, you are at too great an angle to the current. It is the current that moves you sideways & the amount of sideways depends on the speed of the current & your angle to it. Simply straighten up a bit. If you are heading directly into the current you will not move sideways at all, just a little forward or back depending on your speed relevant to the current.[/QUOTE

Searush has this dead right - just parallel up a bit out then use a small angle to gentle glide in! enjoy its one of the most satisfying parts of boating!

 

[hlb]

Rin
If you are moving sideways too fast, you are at too great an angle to the current. It is the current that moves you sideways & the amount of sideways depends on the speed of the current & your angle to it. Simply straighten up a bit. If you are heading directly into the current you will not move sideways at all, just a little forward or back depending on your speed relevant to the current.

Hiya. Were in the river at Conwy. Ferry gliding is quite interesting with a seven knot tide. No prob for MF though. Just need the slightest turn from the current, only a degree or two. More interesting is doing it backwards, as the HM insists that all boats face upstream.

Interesting setting off as well, as you have to get up to seven knots, before letting go.

 

[RIN]

Thanks for the advice everyone, even peanuts

Have just replaced fenders so have put the old ones on pontoon and hope to do some pontoon bashing tomorrow lunchtime
Richard