Log of SV Free Spirit and ships company

The chronicles of the schooner Free Spirit and her crew, embarking on an open ended journey upon the great rolling heap. Free Spirit is currently pursuing humanitarian and commercial goals in the Dominican Republic, on the island of Hispaniola. Working under the Ocean Reach USA and Paradigm Research banners, she is serving as logistics headquarters, workshop, and development laboratory for many ongoing projects. This is the log of her journey.....

Web sailfreespirit.blogspot.com
If you are joining us for the first time, click here for an introduction!
Books and more, at the Schooner Free Spirit Chandelry
Clothes and more, at the Free Spirit Logo Shop!

Thursday, April 02, 2009

Day Sail To Little Africa ~ Dry Tortugas

We brought aboard 5 campers from the small campground at Fort Jefferson for a day sail and snorkeling at Little Africa Reef. It is located on the far side of the lighthouse island about 5 miles from Fort Jefferson. Only a couple of them had kayaks, so it was great to take them along for the adventure. They all enjoyed helping with the raising and lowering of the sails and anchors for the trip.

Workin' hard!

The boys were able to take a small break this trip, due to all the extra deckhands.

Dez, climbing the aft mast to....

check out the view from the Crow's Nest.

Lighthouse Island

Bretton, bringing the camera to Dez....

For this adventure, we had 12 of us in the dinghy and the kayak; along with all of our water bottles, life jackets and snorleing gear. Our little 2 hp motor worked at least quadruple time to get us all a bit closer to the reef from Free Spirit.

Big, big shells

I was disapointed that this picture was a bit blurry, but I had just taken it out of the water. Bretton AKA The Great Snorkle Monster of the Dry Tortugas :-)


A few underwater reef shots to help you join us in our experience!

A quick dip to wash away some of the sand from the beach.

For our sunset cruise back to Fort Jefferson, I put out a spread of appetizers. We were all pretty famished from our busy day enjoying the water, sun and sights!

~ Peace ~

Sunset during anchoring.

The weather is almost always the deciding factor in our plans. Although completely unplanned, we ended up pulling anchor about 45 minutes after this shot to head to Marathon in the Florida Keys. We all would have enjoyed another couple of days in this paradise, but calm seas and fair winds called us once again!


Blogger Gayle said...

We live life. You love life.

Thanks for taking us along on your journey.

6:20 AM  

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Introducing Propcalc 4.0

Use Propcalc to easily match your hull with your engine, transmission, and propeller
Put the known data in the top fields, then hit the Update button to get the answers.
Results, of course, should be verified by a Naval Architect or qualified surveyor.
Data is provided for three bladed propellers of average type
For two or four bladed props, use the modifiers shown below.

Fill out the fields as follows:

Vessel LWL (ft) = Waterline length
Vessel Disp (lbs) = Vessel displacement
(max) HP = Rated Engine Max HP
Engine RPM max = Engine RPM at Max HP
Engine RPM cruise = Desired or estimated cruise rpm
(Cruise or Max) Kts = Speed to work the calculations for
Slip = Propeller efficience. 45% is average for a displacement cruiser.
Gear ratio = 1: Gear ratio of transmission
SL Ratio Adj. = This value will be added (or subtracted, if a negative value) to the calculated S/L ratio.

Key information:

If the "hp required" is greater than the "cruse HP", you have your cruise RPM set too low for your engine parameters.
If the "hp required" is significantly less than the "cruse HP", you have your cruise RPM set too high for your engine parameters.
If the "hp required" is greater than the "Max HP", then your target speed is too high for your engine/hull parameters.
The S/L ratio is calculated automaticaly based on your input. It can be adjusted if necessary, but normally it should be left alone.
If the calculated S/L ratio exceeds S/L MAX, then the results are likely to be non-predictive. Try a lower speed requirement.
SL Ratios of 1.1 - 1.4 are typical of displacement hulls. Semiplaning or planing hulls can go higher.

Typical propeller slip values:

Sailing auxiliary, barges, etc less than 9 Kts............45%
Heavy powerboats, workboats 9 - 15 Kts....................26%
Powerboats, Lightweight Cruisers 15 - 30 Kts..............24%
High speed planing boats 30 - 45 Kts......................20%
V bottom race boats 45 - 90 Kts...........................10%


it is possible to get irrational answers by irrational input , I.E specifying excessive speed for hull type and length
Any attempt to exceed hull speed (1.34 times the square root of the waterline length in feet) with a displacement hull are likely
to fail unless the hull is extremely fine (multihull) or otherwise exceptional. In such cases, an S/L adjustment would be in order.

2 and 4 bladed props:

For two bladed propellers, multiply the diameter by 1.05, and the pitch by 1.01
For four bladed propellers, multiply the diameter by .94, and the pitch by .98

Vessel LWL (ft) =
Vessel Disp (lbs) =
  (max) HP =
  Engine RPM max =
  Engine RPM cruise =
  (Cruise or Max) Kts =
  Slip =
  Gear ratio = 1:
  SL Ratio Adj. =
  Prop rpm max =
  Prop rpm cruise =
  Pitch =
  Diameter =
  Static Thrust =
  Cruise HP =
  Cruise HP% =
  SL Ratio =
  DL Ratio =
  SL Max =
  HP Required =