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The 30' Rescue Boat

"ERNEST SHACKELTON"

Copyright 2016 Michael Kasten

30' Ernest Shackelton - Kasten Marine Design, Inc.

Shaded Perspective Above Aft | Shaded Perspective Above Forward
Clear Perspective Above Aft | Clear Perspective Above Forward
Artist's Sketch Aft | Artist's Sketch Forward
Rendered Perspective Aft | Rendered Perspective Forward

Artist's Sketch at Bow

30' Ernest Shackelton - Kasten Marine Design, Inc.

Four Designs - Shared Characteristics

As with the 33' Freyja, the 44' Valhalla, and the 66' Asgard designs, inspiration for this design was drawn from Viking craft, as well as from Coast Guard surf boats and whaleboats, all of which were double ended in their original form.

One whaleboat in particular, the James Caird was purpose-built for Ernest Shackelton to take along on the Antarctic voyage on which his ship Endurance was crushed by the ice. The whaleboat allowed Shackelton to sail from Elephant Island at the north end of the Antarctic Peninsula where his crew were marooned, to South Georgia Island where a whaling camp was known to exist, more than 800 miles distant. Shackelton's voyage in the whaleboat James Caird was one of the greatest sea voyages of all time.

The design shown here would have been a luxurious vessel to Shackelton...!

A simple structure is used so that the vessel can be built quickly and economically. Aluminum provides an extremely rugged hull as well as light weight for the sake of trailering... The goal has been to create an easy to build, affordable, easy to trailer, easy to sail, easy to beach, and easy to inhabit boat that can also be used in extremis as a rescue craft just as Shackelton had used the James Caird.

Being a sailing vessel, for the sake of easy trailering a tabernacle will allow the mast to lower without any fuss. A centerboard or tandem centerboards or leeboards can be used. If a centerboard or tandem centerboards are used, they should not interfere with the interior accommodations. But leeboards completely eliminate such troubles... and... they eliminate another complexity of design, i.e. the centerboard and the trunk that must house it...!
 

Specification...

Design parameters have been defined as follows:

General parameters:

Structure:

Mechanical:

30' Ernest Shackelton - Kasten Marine Design, Inc
Click for Larger Image

Interior

In the 'basic' rescue boat configuration, bench seating is planned within both cabins, more or less identical, as drawn.

In a fancier version, a simple galley could be located just inside the forward cabin, with seating as shown in the sketch, plus a center table. The galley is located forward because there is more headroom. If built as a "yacht" the forward companionway hatch would be made fairly large so that one could actually stand up in the galley. With a canvas dodger over the forward hatch, this is weather-friendly even when raining.

In the aft cabin, a bureau / hanging locker can be located to one side forward, with an enclosure on the other side for the head. The rest of the aft cabin would be settee berths which could easily be made into a large double berth by the addition of 'drop boards' between.

In the cockpit there is plenty of room for a marine diesel engine below the cockpit sole in the aft part (aft of the amidships bulkhead). Below the cockpit sole forward is a large gear locker - more or less assuming the functionality of a lazarette locker. The cockpit is of sufficient length to allow a person to sleep on each side sort of like a quarter berth, but located amidships. A canvas awning over the whole center cockpit area would provide excellent shelter from rain and sun.
 

Size & Layout Options

The 30 feet on deck length is perfect in order to achieve a five foot spacing for the transverse structure. This allows two full bulkheads at the 10 and 20 foot mark, plus one half-bulkhead amidships, and then one frame in each end cabin at the 5 and 25 foot mark. This provides a ten foot cockpit with a pair of ten foot cabins in each end. This is extremely elegant in terms of structure, since there are three bulkheads and only two frames...! 

Per the ABS Rule as it applies to aluminum vessels the five foot spacing works well for the transverse structure, but that is roughly the maximum.  This layout would be exceedingly simple, if not downright Spartan.  It is after all a "rescue boat" concept.

Staying with the 30 foot length, and placing frames on 28" centers would provide other interior options.  This would allow a bulkhead at each end in order to provide a forepeak and lazarette.  Amidships it would provide a 7 foot cockpit, just right for sleeping on deck.  Between the cockpit and the end bulkheads is a space of 9' - 4" at each end, which allows for a 7 foot settee forward and the same length as a double berth aft, leaving one module of 28 inches in each cabin adjacent to the cockpit bulkheads.  In the aft cabin that would be used for a head to one side and bureau opposite. In the forward cabin, that would allow a 28" length for a galley on both sides.  This would be quite similar to the layout on the 33' Freyja, except that in this case the cockpit is less long, and there is less length available for the galley and head compartments.
 

30' Earnest Shackelton - Kasten Marine Design, Inc.
30' x 10' Earnest Shackelton With 28" Frame Spacing - Click for Larger Image
 

Alternately, using four foot modules, one could easily expand the concept to having a 12 foot cabin in each end with an 8 foot cockpit, for an overall length of 32 feet. The added cabin length would be very desirable, and also keeps the cockpit length sufficient for sleeping outdoors.  Again, this layout would be quite similar to the 33' Freyja.
  

Trailering

Most US states do not require a chase car until width exceeds 10 feet. Some states allow 8.5 feet without any special permit. Most states allow oversize loads either by simply providing a sign and / or lights, or by securing a permit. The common denominator is 8.5 feet for the most part. The vessel can become more narrow if necessary, however it will be at the expense of increased draft in order to carry the same load. A narrower beam will also degrade initial stability and sailing ability. As a result, I have targeted a minimum beam of 9 feet, but for the 30 foot size a beam of around 10 feet is optimum. If the design were made larger, I would increase beam to suit in order to keep it in proportion.
 

Rig

A simple Gaff Rig was originally planned.   But an alternate option is the Chinese Lug rig, as shown in the image above.  The choice in favor of a ketch arrangement is based mainly on wanting to achieve good balance, and also to keep the masts out of the way of traffic.  This way, the main mast is at the forward end of the table (assuming there would be a table between the forward settees), and the  mizzen mast is right at the foot of the V-berth aft, also out of the way for the most part...  For this rig a boomkin is shown which has the purpose of handling the mizzen sheets.  It also happens to be convenient as a davit for sailing in mild conditions.

The spars are aluminum Schedule 40 pipe, which is considerably stronger than wood, and does not rot!  Pipe has sufficient wall thickness to allow the fittings to be fully welded in place, making the whole affair very easy to build.  Fabrication of the aluminum fittings requires far less time than making similar galvanized steel fittings for a wood spar.  In the long run there is much less maintenance than is required for a mast of any alternate material.

If a sail rig is introduced, the keel will ideally be deepened as shown in the sail plan above, or there will have to be a substantial centerboard.  In any case, the rig should be kept low for this kind of keel configuration.  The overall concept is to achieve a vessel that is easy to launch from a trailer, or from the beach... 

If it were to be considered important  to optimize windward ability to the max, then of course other keel configurations would be considered, as well as a higher aspect rig.  Even so, the design would be aimed at ultimate survival, a la Shackelton. 

The images in the links below show the concept of adding bilge keels, mainly so the boat can sit upright when taking the ground at low tide, but also in order to benefit windward sailing ability.  With the bilge keel configuration, there is no need for a centerboard.

Artist's Sketch Above - Bilge Keels | Artist's Sketch Aft - Bilge Keels | Artists Sketch Forward - Bilge Keels 
 

The Concept

Having been originally conceived as a rescue craft much in the vein of Shackelton's whaleboat, what we have here is a truly pelagic vessel - one that perfectly illustrates my ideal Nomadic Watercraft.
 

Other Designs In This Series

30' Ernest Shackelton | 33' Freyja | 44' Valhalla | 66' Asgard | 77' Schooner ODIN

30' Ernest Shackelton - Kasten Marine Design, Inc.

Trailerable Boats Article