A dive boat is a boat

Boat

A boat is a watercraft of any size designed to float or plane, to provide passage across water. Usually this water will be inland or in protected coastal areas. However, boats such as the whaleboat were designed to be operated from a ship in an offshore environment. In naval terms, a boat is a...

 that scuba divers use to reach a diving site which they could not reach by swimming from land.

Dive boat features

Features that make a boat suitable for use by divers are:

• marine VHF radio
  Marine VHF radio
  Marine VHF radio is installed on all large ships and most seagoing small craft. It is used for a wide variety of purposes, including summoning rescue services and communicating with harbours, locks, bridges and marinas, and operates in the VHF frequency range, between 156 to 174 MHz...
  
  
• oxygen first aid
• diving shot
  Diving shot
  thumb|right|Diagram of a diving shot upcurrent of a dive siteA diving shot is an item of diving equipment consisting of a weight, a line and a buoy. The weight is dropped on the dive site. The line connects the weight and the buoy and is used by divers to move between the surface and the dive site...
  
  

For larger boats these facilities may also be present:

• diving air compressor
  Diving air compressor
  A Diving Air Compressor is a gas compressor that can provide breathing air directly to a surface-supplied diver, or fill diving cylinders with high-pressure air pure enough to be used as a breathing gas.thumb|right|Filling a cylinder from the panel...
  
  
• gas blending
  Gas blending
  Gas blending or gas mixing is the filling of diving cylinders with non-air breathing gases such as nitrox, trimix and heliox.Filling cylinders with a mixture of gases has dangers for both the filler and the diver. During filling there is a risk of fire due to use of oxygen and a risk of explosion...
  
  
• recompression chamber

Types of dive boat

Many types of boat can be used as dive boats. Some notable types of dive boat are:

• the rigid-hulled inflatable boat
  Rigid-hulled inflatable boat
  A rigid-hulled inflatable boat, or rigid-inflatable boat is a light-weight but high-performance and high-capacity boat constructed with a solid, shaped hull and flexible tubes at the gunwale. The design is stable and seaworthy...
  
   (RHIB or RIB)
• the day boat
• the live-aboard

Rigid-hulled inflatable boat

Divers only spend a few hours at a time on these fast but exposed boats. The boat being small and easily transported on roads, is suitable for amateur use. These boats should carry basic safety equipment such as marine VHF radio and oxygen first aid.

The divers enter the water by rolling backwards overside, and return to the boat by climbing back in over the soft rounded tubes after removing the heavy parts of their heavy diving equipment

Diving equipment

Diving equipment is equipment used by underwater divers for the purpose of facilitating diving activities. This may be equipment primarily intended for this purpose, or equipment intended for other puprposes which is found to be suitable for diving use....

 and handing it up.
An advantage of this type of boat compared with similar-sized rigid boats is that the inflated tubes make the boat very stable during the entry and exit of the divers.

Day boat

These boats are made of rigid materials - often, fibre glass. Day boats are quite large: typically, between 60 to 90 ft (18.3 to 27.4 m) in length. Many day boats are used for scuba-divers, but may also be used for any other marine enthusiasts. In general, divers or passengers will spend only the daylight hours on a day boat, and do not usually sleep in them overnight. (They will usually only sleep overnight if they are on a "live-aboard", which is a slightly different sort of boat). Generally a professional crew navigate and operate the boat. The boat provides shelter from the weather and is likely to have various facilities and area's for the passengers, such as: a toilet (called the "head") and a small kitchen (called a "galley"), which is often manned by a cook who cooks lunch for all on the boat. Day-boats usually also have a lounge (called a "saloon", where divers can relax on upholstered benches), and one or more dining tables. Many day boats also have an uncovered sun-deck outside, as well as a shaded area, for divers wishing to be out in the open air. The boat will usually have a diving air compressor, oxygen first aid, a VHF radio, a GPS and possibly gas blending facilities.
In the case of divers, a day boat would be used to ferry divers to multiple dive-sites (typically between one and three sites) during the same day.

The divers enter the water by stepping off a platform and return to the boat using a ladder or a lift. Or they may transfer to and from a RIB ("Zodiac"(tm) or "rubber-duck" type inflatable boat).

Live-aboard

With these commercial boats, the divers live and sleep on the boat and dive from the boat for a few days to several weeks. A crew navigate and operate the boat. In addition to the usual domestic facilities expected by hotel guests, the boat will have a diving air compressor, oxygen first aid and possibly gas blending facilities and even a recompression chamber in some cases.

The divers enter the water by stepping off a platform and return to the boat using a ladder or a lift. Or they may transfer to and from a RIB which is carried and launched by the live-aboard.

Liveaboards used on the West Coast of Thailand and in the Red Sea

Red Sea

The Red Sea is a seawater inlet of the Indian Ocean, lying between Africa and Asia. The connection to the ocean is in the south through the Bab el Mandeb strait and the Gulf of Aden. In the north, there is the Sinai Peninsula, the Gulf of Aqaba, and the Gulf of Suez...

 tend to be up to 100 feet (30.5 m) long and to have:-

• The lowest deck, which is for the engine and stores.
• The lower deck, which is all or mostly cabins for the passengers, usually two passengers per cabin.
• At the stern, a small diving deck with diving ladders.
• The main deck, which has the dining / social room, and crew bedrooms, and the main bridge, and open space.
• One or two upper decks.