Divers and Cats

[skipmac]

Originally Posted by Randy

You know I'd been thinking about diving in the tropics and sometimes like on the Great Barrier reef it seems like snorkling is all most as good as diving but then you get to wall dives the stuff just continues & before you know it you're deeper than you thought with the clarity.

Also the wreck sites in Truk & the Solomans are really fairly deep.

On a small multi I'd thought how to get a compressor set up. I gave up with knowing you've got to have a quality compressor & the weight issue.

Took a boat to Bimini/Cat Cay a few years ago for a dive trip. The two best dives of the trip were one on a wreck aground in 25' of water, the other on a wall in the edge of the Gulf Stream at 250'. Nice if you could have a boat set up to do either.

On compressors, you can get some quality compressors in smaller sizes (relatively speaking) but will have to deal with much longer fill times. An old friend sells yacht systems and could offer some advice. Not sure if it is allowed to post commercial web sites. Send me a PM if interested and I'll send details.

[skipmac]

Originally Posted by peter.bomberg

Hi Skipmac, funny I did my calculations on very similar model, the issue I ran into was a cost question and a supply issue both He and O2 are really pricey in most of Asia and if I am in the outer islands in Fiji for 2+ months then I either pay a fortune (and head back to Nandi) or switch to OC.

I am willing to reduce the amount I carry with me if I have to but only once I realize how heavy my barge has become, lets face it if it's max speed is under 8knts it's painful to make any long passage but compromising and giving up on the 20+ I wanted (and realize I was being silly about)

Have heard the same complaint about costs for dive gas in Asia. We did an informal poll on a diving forum a few years ago focusing on He costs around the world. In a lot of the third world He was really expensive if available at all but some spots it was not bad.

Not sure about overseas but in the US we have confirmed that commercial or welding grades of He and O2 are exactly the same as "breathing" or high purity grades. Anecdotal evidence suggests the same situation overseas and even out of the way islands usually have pretty good welding operations. Have you looked into that channel for gas?

I came to the same conclusion on cats and performance. On paper you could get a cat to do 20 kts, but when you start adding galley, head, stores, water tanks, refer, AC, tools, spares, etc you end up with just a little better than a mono. OK, before the multi hull guys jump me, maybe a lot better but not 20 kts unless you get something 60-70' or better that is big enough to carry the comforts for cruising without the weight bogging down the boat.

[TANKWA3]

HI PETER I READ WITH INTEREST AND A DEGREE OF ENVY YOUR PLANS TO PURCHASE A CATAMARAN FOR DIVING WORK BUT NOTICED THAT U MADE NO MENTION OF SOUTH AFRICAN DESIGNED AND BUILT CATS AS POSSIBLE CONTENDERS IN THE LIST OF CATS U HAVE CONSIDERED. SOUTH AFRICA AFTER FRANCE IS SECOND IN THE WORLD AS FAR AS CAT BUILDING IS CONCERNED AND PRODUCES LARGE NUMBERS FOR THE MOORINGS GROUP THAT HUGE CHARTER COMPANY OPERATING ALL OVER THE WORLD. THESE ARE IN THE MAIN BUILT MOSTLY AROUND CAPE TOWN .THE CHARTER INDUSTRY HAS SUFFERED A HUGE DECLINE IN BUSINESS AND THE BUILDERS ORDER BOOKS ARE DOWN BY AS MUCH AS 80% SO NOW MIGHT BE A GOOD TIME TO PICK UP A BARGAIN .FOR EXAMPLE AT THE MOST RECENT CAPETOWN BOATSHOW A 50FT OUT OF THE BOX WAS SELLING AT 5MILLION RANDS. THERE ARE APPROX 8.35 RANDS TO THE USD. NOW THIS WAS A REALLY BEAUTIFUL VESSEL WITH EVERYTHING YOU OR YOUR WIFE COULD WANT . I DONT KNOW ENOUGH ABOUT LOAD CARRYING CAPACITIES BUT CAN ASSURE YOU THAT THE STANDARD OF BUILD IS FAR STRONGER THAN THE FRENCH CATS AS THEY HAVE BEEN DESIGNED TO WITHSTAND NORMALLY MUCH HARSHER SEAS AROUND THE AFRICAN COAST THAN IN THE MED FOR EXAMPLE. IF U WANT ME TO DO A BIT OF RESEARCH ON YOUR BEHALF , BEING A DIVER AROUND THE CAPE OF GOOD HOPE AND HAVING ENJOYED MORE THAN ANYTHING ELSE OWNING MY OWN 36FT CAT PLEASE FEEL FREE TO INFO ME REGARDING YOUR LOAD CARRYING REQUIREMENTS AND I WILL CONTACT THE BUILDERS AND ASK SOME NB QUESTIONS ON YOUR BEHALF. SWEET SAILING AND DIVING TO YOU . REGARDS DAVID

[peter.bomberg]

Hi Tankwa3, I like some of the South African cat designs, the reality is I don't care to much what the cat is (custom or stock) French, German, Swedish, South African, etc... The factors that will decide are layout, price, specs, performance and load carrying capacity. I will buy a used cat as I don't believe in new (probably 5 years or close to that) and I expect to do a fair amount of modifications once I buy it (everything from possibly converting to solar/regenerative and pure electric drives), extending the bimini to cover the dinghy and cover it in solar cells, cutting out access to the dive/storage room at the back (yes taking out a whole bedroom and bathroom to make room for dive and storage, etc... I am estimating 1-200K in modifications if needed, including the navigation system (going fully integrated some thing like the G-Series from Raymarine or the 3D from Furuno with a redundant GPS and a couple of other aspects), wired sound and so on, but the reality is I am far away from there and the purpose of this post was to figure out what range of Cat do I need to focus on depending on the load, I am pretty sure from my quick analysis (read many more months of work left and 100's of what if situations) that I am going to be in the 45-55 foot range and aiming for a load of about 4 tons all inclusive (however this includes many items that are standard such as engines, A/C, water tanks, etc, so the additional load may be in the 2 ton range, and it appears that is within the tolerance of 45-55 foot cats (I will post the spreadsheet and so on later when I get there (still in VERY draft form)

[Sterling]

wait - you're seriously considering making your own mixed-gasses on board? hugeeeee waste of time / space / energy, IMHO. you can get a max-air compressor for under 5k and dive with air all you want. two cylinders will charge in about 90 minutes - a reasonable surface interval anyhow, and you'll be set.

if you *really* want mixed gas i'd just carry a dozen cylinders and get them recharged at your destinations. the amount of energy it would take to power / carry the equipment needed to DIY just isn't worth it.

edited portion-

i just read-read your post about the technical aspect. i respect your goals, but i still thing you're overcomplicating matters. remember that the whole purpose of a trip like this is independence and self reliance. if one of these many mechanical tools breaks, you're aced. go simple and purchase gas as needed, where you can when you can. yes, you may be paying more per unit, but at least you won't have that large (massive?!) lump sum to deal with upfront. breath air and limit your depths 80% of the time and keep the technical stuff in moderation. you'll have 1000x less hassle / expense and 99.9% the pleasure.

[peter.bomberg]

Sterling, I had not thought of that option but you are right and it makes it easier too, carry 2 K cylinders premixed at 10/70 and one K cylinder of pure O2 then all I need to do when out is top up the breathers tanks as needed (simple booster pump) and it would give me a full range (up to 330 feet) and then just have a 40% O2 capable compressor for the OC aspects, and you have a point (I need to recalculate the 3 K cylinders as I may be asking for way more bottom time then I really need (there are 2 of us but my wife is happy on OC), rough calculations I should get about 8 breather fills per K cylinder using a booster pump and lets just for sake of argument make each 3hrs that would give me 24hrs of dive time on a tank and that may be enough to refill, ok more thoughts now!

[Sterling]

i think you've hit on a winning solution. loads of flexibility, minimum upfront cost, least possible tonnage in the boat.

plus, regarding your concern about spreading the weight - you could keep extra cylinders spread between hulls, to aid in balance and distribution. keep the machinery in the port hull, store tanks and weights in the starboard, etc.

[peter.bomberg]

Hi Sterling, agree and I was looking to actually place the breathers in the fore peaks in shells during passage as they are bulky, however I think I just found my Cat! (ok have to wait for 5+ years for it to become affordable but the Outremer 49 looks down right amazing!

(If I figure out how to embed a pic I will, but looks like speed, comfort and least mods as it's a 2 bath 4 bedroom config (like I want as opposed to the standard 4/4) as I only need to modify 1 room, have to figure out how to get rid of the sail drives and swap to shaft drive (or at least I think I do), and who knows swap the diesel for electric (in 8 years I think it will be the norm)

[imagine2frolic]

YouTube - Catamaran Alize - Atlantik Crossing

YouTube - Catamaran Samsara Sailing Very Fast

Kind of sailing like this?.....i2f

[peter.bomberg]

nice and well after I load it up it wont fly like that but 10+ knts would be nice and from what I see the 49 with my extra load will still be in the 14 range (sadly it's about 100K more than I like when I add in the options I like and may be out of my range

[imagine2frolic]

Imagine is 46 ft. Weighs about 15,500, and hulls are about 12 to 1 maybe a wee bit higher. When I bought her she had 2 folding motorcycles, and the previous owner took over 1k pounds off of her. When he went to the airport he took 6 huge bags of luggage. He left behind tools, dinner ware, snorkel for a dozen, bedding, fishing equipment. The boat was fully loaded for cruising . I just brought my swimsuits, and a few extra tools. With all of this, and us 3 on the boat we hit 18 1/2 knots under spinnaker. We were doing about 12- 13 knots in a 18 knot breeze. Coming in from the Atlantic betwen St. Maarten & Barts we got a little extra puff on the top of the wave, and that's when she accelerated.

Hitting these speeds are no problem maintaining them is another thing. Look at the statistics in the ARC. The cat will keep up with a bigger mono, and it will be more comfortable, and to me the comfort is the big thing along with being on the hook. I think if you settle for an average of 10 knots. You will not be disappointed. If you notice on all the cat sailing videos. They show the knot meter, and the meter peaks at that speed. It's not what she is maintaining.

Keep looking, and you will find something to fit you. I wasn't even looking for a cat. I was looking for a mono. When Imagine jumped onto the screen for it's price I asked what's wrong? Turns out I was in the right place at the right time with cash in hand.....i2f