Comment

Comment by Raymond Julian on July 7, 2011 at 9:26pm

I have spent many years watching vessels up to several hundred feet in length at anchor.  In even mild breezes the vessels swing.   I stand by my previous comments and hope the operators of the ship will determine if this is an issue BEFORE they go too far in the design process.

Comment by Bob Simmons on July 7, 2011 at 10:19am

Unfortunately I will not be making it to Oshkosh this year.  Take lots of pictures.

Comment by Jonathan Porter on July 7, 2011 at 4:36am

Thanks for keeping this running... we will tell you all more at Oshkosh!! come and see us at the Zenith booth!

FYI The hospital ship is, for whatever reasons (DONT ASK) not being used and unlikely to be released for use. SO, we, being the types that we are, are going to build a 'Health Education Vessel' curently we plan that  it will have a 30' wide steel catamaran hull, with two beachable launches that will form the U shaped dock for the aircraft.  Remember the aircraft will rarely spend more than one hour docked - it will be busy - and normally return to the hangar at the airfield at night (for a rest and more fuel).

see below for some outline ideas that we are working on... more will come out at Oshkosh!

Comment by Bob Simmons on July 6, 2011 at 2:43pm

This isn't a boat.  It's a hospital ship.  Any conditions that would cause a vessel that size to 'oscillate' will have probably long since grounded aircraft.  And I assumed any floating platform would have more than one anchor/mooring point to prevent movement.  Otherwise I would never consider taxiing an aircraft onto it.  The attachments would need some slack to accommodate wave motion and the like, preferably with some elasticity rather than complete slack.

 

However, now that you bring the subject up,  I did consider the U design further after initially offering it and decided it probably isn't really essential with a 'taxi-on' configuration.  With the proper design and flotation, the 'arms' could be eliminated entirely, which would grant much greater leeway in taxiing onto the platform, though you might want to at least consider some type of guard or rail to prevent a float from sliding off the edge.  There is one possible disadvantage to eliminating the arms.  It could reduce the ability to dock other aircraft to the side of the platform.

Comment by Raymond Julian on July 6, 2011 at 2:05pm

One thing to keep in mind in operations involving an anchored boat is that the boat is very seldom actually sitting still.  It typically oscillates on it's anchor.   This may make threading the needle into a U shaped dock a problem occasionally.  I would build the dock off the stern with the u facing away from the boat.  This would allow you to motor into the wind if conditions required and the aircraft would be able to overtake you and enter the dock.  I think being able to get the dock out of the water offers several advantages.  I addition to decreasing drag it allows you to pull the dock out of the water when things are rough and decreases the wear and tear when the dock doesn't need to be in the water.  Someone else mentioned maintenance is easier.

 

Another dock shape that you might consider is an "L".  Although not quite as convenient as the "U" it offers more approaches and once the aircraft is docked inside the "L" it is easy enough to swing the airplane from one leg to the other to gain access to both sides of the airplane.   A "T" would allow 2 aircraft to alternately use the "upright of the "T" while the other was swung out of the way onto the underside of the "cross arm.  The "T" would allow docking 3 aircraft  with ready access to all 3.

 

Well, this has been brain dump.  I hope you find something useful 

 

 

Comment by Bob Simmons on May 20, 2011 at 5:23pm

Jonathan,

 

I read the article about you and Medicine on the Move in Plane & Pilot magazine.  Very nice.

Comment by Bob Simmons on May 12, 2011 at 8:38pm

By the way, I recommend you make the dipping portion of the platform hinged so that it can be winched out of the water.  That will minimize maintenance, make maintenance easier and lower algae growth.

 

The dip needs to be gradual too.  You can't simply have one angle downwards at a single pivot point unless you have a very long platform, because the floats would bottom out trying to cross over that single angle.  For instance, if you want the dipping portion to pivot down a total of 30 degrees you want to build in three 10 degree pivot points as opposed to a single 30 degree pivot point.

Comment by Bob Simmons on May 12, 2011 at 8:12pm

If you plan to preposition moorings and want more bulky construction for the platform, why not preposition moored platforms with hinged gangways that can be winched up to the gunwale of the vessel when it arrives at each location?  Would platforms be safe if you prepositioned them and left them in place? Obviously that would require more materials and construction, but it would eliminate or at least minimize towing requirements.  It would also add some level of redundancy.

 

And if the construction was bulkier you probably wouldn't need the 'arms' on each side of the dipping portion of the platform.  That would make taxiing onto it easier, though you may want to consider some 'bumper guides' along the side of it similar to the guides some people use on the side of their boat trailer to make sure the boat goes on straight.  That would just be a last ditch safety precaution to ensure a float doesn't slip off the edge of the platform as the aircraft is taxiing on.

Comment by Jonathan Porter on May 11, 2011 at 1:00am

some great ideas!  Sebastian, I love that concept!  For interest we are unable to drop an anchor from the boat... unless we use disposable anchors... this is the largest man made lake in the world, the lake bed is old trees, shrubs and buildings.  Those who drop anchor cannot raise it again - it gets stuck in the debris.  Therefore, we plan to build a number of mooring cages/buoys that we would drop from a barge to predetermined locations.  We have identified nearly 1000 villages within the first two legs of the lake, neither more than one hours flight from our base, but many of them more than a day by other modes of transport.  

Such a base will be so vital to so many that it would need to be well engineered, like the Zenith Aircraft, and although we may use barrels for other applications, this one would need more bulky construction.  I really like the idea of the 'ride on top' dock with a climb out dip, which would make pre-flight easier too.  Please keep the ideas rolling, you have no idea how much they encourage us and provide the inspiration necessary to keep on fighting to make this stuff happen.  

Comment by Bob Simmons on May 10, 2011 at 10:02pm

Something along these lines is what I was talking about.

 

The grey area would be the part that dips down so the aircraft could taxi onto the platform.

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