Red Sea Dive Boat

After a few false starts and some earlier threads - it is time to make this happen.

So starting from the beginning - the knowns/limitations etc -

The local laws in Egypt mean that to "easily" get a dive boat licence the boat needs to be 12 metres in length or less, and the local laws are that one person (crew or guest) per metre of length is allowed - so therefore the ideal LOA is 12 metres.

Hull and superstructure will be aluminium. Helm stations on a flybridge and in the cabin. Cabin offset to starboard so as easy to move along the port side to tie up the vessel while facing into the predominate wind at the local pile of rocks and concrete that is somewhat optimistically referred to as the jetty.

Motors will be twin outboards, local "laws" imposed by the coast guard in the Red Sea are that outboards are limited to 300hp each - but there is no limit on how many, however I want to fit a diver lift on the transom so I don't expect that there will be room for more than two outboards. Likely outboard brand will be Suzuki.

Load will be two crew + ten divers (including dive guides), given that the divers will often be what are called tech divers who take a **** ton of cylinders and gear to big depths, the total weight for crew + divers is estimated at max 1900 kg.

Desired cruising speed is 20-22 knots

This is the operating area -


So first questions -

Any other questions?

Monohull or cat?

Planing or semi-displacement like the previously discussed Poleson Marine catamarans, or full displacement?

Stability at rest will be a key consideration as there will be divers carrying 60+kg of gear wandering around on deck trying to get to the stern to jump in.

 

How does Egypt measure the length? If it is overall then it would include items like an anchor bowsprit, swim platform, outboards, etc. that overhang.

 

That is the question that nobody seems to know the answer to - in Egypt a lot of rules are interpreted locally - and the further you are away from Cairo the more flex in the interpretation. I don't believe that it would include outboards, so what I am thinking is make sure that LOA including anchor bowsprits etc is right on 12.0, and make sure that waterline length is at least 11.0 - that way I know that I will be allowed at least 11 - and I can make it work with that.

 

Are your saying they measure the length at the waterline and not overall?

 

No - just saying that given I don't know which measurement method they might use on the day, if the waterline length is at least 11 metres then if they use that method then I will get approval for at least 11 people. Given how vague things are there I can see axe bows becoming popular

 

I can see the dilema if it is up to the interpretation of the inspector. From what you are saying, they don't approve plans but a finished boat.

 

What is the budget?
Is this recreational deep, long duration diving or commercial?
How deep and why ( I am a retired PADI Instructor and underwater construction diver )
Do you hang tanks from the boat as well? Safety stops?
What is the time frame for "making this happen"?
Is this strictly a dive boat, no other use?

Cat, no question, but it may be a challenge to make 22 knots with 2 x 300 hp o/b's on a 12 meter, 12-passenger boat.
With a wide enough cat, you could make provisions for two more outboards if needed to make your 22 knot bogie.

If it's a cat it'll be... well... a cat.

 

I would never want divers near the outboards. It seems like a dive deck off one side of the aft bdeck or the aft section of the aft bdeck would be better. (?hydraulic?)

Maybe you can get the transoms wide enough that you are far enough away. I’ve struggled much trying to come up with a way on a narrow transom to get back on my boat in mob situation.

But diver boarding should be well planned. Even to recover an injured diver deserves consideration.

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Have you done any weight estimates?
What's your total and how accurate?

60kg x 10 divers is 600 kg of dive gear
12 people and their personal kit is over 1200 kg

 

I would recommend a wide-beam monohull with a large work area aft and with the smallest freeboard allowed by regulations. Access to and from the deck for divers should be as comfortable as possible. This makes catamaran-type vessels less suitable, as the freeboard on them is usually greater than on a monohull.

 

Here are a few photos of the 49' (15 metres) aluminium cat that was designed and built here for a local tour operator 24 years ago.
It is the cat shown in my avatar photo.
She has 2 x 150 hp O/B motors now - when they were initially installed, she achieved a maximum speed of 26 knots with 10 people (but no gear) on board.

She was originally fitted with a wide bow ramp, as they would carry 40 passengers and do beach landings for kayaking tours.
This mission statement later changed, and she now does only snorkelling tours, so we took off the bow ramp and built a bow ladder between the hulls as shown.
Both were always far away from the outboard motors!
The bow ramp was very useful for recovering overweight / unfit people from the water, as they could just swim up on to it, rather than having to climb a ladder.



When she was first built she had 2 x 70 hp O/B motors (as per the photo below), and with these she did a maximum speed of 16 knots with 10 people on board.



She was later fitted with 2 x 150 hp O/B motors. She is now on her 3rd set of these.



Here is a photo of the original bow ramp :



And a photo of the steps that replaced the bow ramp :



@RSD you should be able to have an 11 (or 12) metre cat with either a bow ramp or a set of steps between the hulls, to keep your divers far away from the outboards?

 

Essentially that is the case, and they don't really approve the finished boat too much either - just confirm length = x number of people, and that it has the required number of life jackets, fire extinguishers and a first aid kit etc.

 

Budget is around $200,000 - but if it needs to be a bit more then it can be.
Long duration deep deco recreational diving on closed circuit rebreather - run times of 2.5 hours for dives to 60 metres / 200 feet
Why is because there is a new wreck and an old wreck both at 60 metres. I'm a retired instructor and commercial underwater inspector too.
Our preference is not to hang tanks from the boat given that it will be live / unanchored, the divers will be carrying their own bailout gas. Normally in the Red Sea the last deco stop is done at 6 metres
Time frame is pretty much as soon as possible, given that there is now a new wreck there at 60 metres which increases the demand for deep dives.
Strictly a dive boat

 

Normal way in the diving world is a platform that is raised and lowered by an electric winch -

 

Crew + passengers + rebreathers and bailout cylinders etc came to 1900kg.