Payload of 30 feet monohull boats?

[hugosalt]

My light displacement 30 fter. comes in at 8500 lbs. (dry)
With every 840 lbs. increasing draft by 1"
In full coastal cruising mode (fully provisioned but only 55 gallons total tankage)
boat with 2 crew comes in at 1,700 lbs.
Boat sails well including in brisk conditions.
Don't know about cruising with 4 for any amount of time, unless all very friendly
and of good nature.

[GTom]

Thanks for all the valuable thougts. It sounds that with careful boat & crew selection the combination of 4 people + scuba + longer passage + <10m LOA is not completely impossible. I am currently looking at Elan 340's, they seem to be roomier than most 30-33' models while staying below 10m, where most marina prices go mental.

[denverd0n]

Originally Posted by Pizzazz

The reason why we get so many different views on this is that people have different perceptions of risk and tend to emphasize worst case scenarios.

I would say that if you are planning to sail across the Atlantic (which is what the OP mentioned) you probably SHOULD think in terms of the worst case scenario.

[a64pilot]

Only place I can think of you could put a compressor would be on deck, and there it will be sprayed with salt water, and that is a lot of money to throw away.
Sugar scoop stern and a good dive ladder and it wouldn't be so bad, but a boat like mine is literally almost impossible to dive from. A dinghy is tough enough

[GTom]

Compressor placement is of course reason for further headache. However, there are <45kg/100lbs models around, that can be stored safe in a cabin and placed on board only when needed. Ideal would be an electric compressor (no smoke=can work below deck) but those usually need 2+kW power.

[bsurvey]

crossing to Hawaii on my 30 ft boat with crew of 4 took 14 days, we had food and water left over. I have sail across the pond to HI 4 times


1 to 2 people on deck at all times.


food was freeze dried and heater meals, no way we even came close to 1000 lbs


are yopu putting a wine cellar on board

[Don C L]

I have a small 29 footer, 8000# displacement, and my friend next to me has a Cheoy Lee 30 footer, 10K# disp.. So 4 people + scuba equipment and compressor, for a long trip?.. I am skeptical. In any case, as has been mentioned, the hull displacement will determine how much more you can add safely, but remember you really need to load all that weight securely as low as possible and as centrally located as possible. My boat originally came with 3120# of lead and later they added 1000# more lead and it was still fine for adding some more for travelling. I have the 3120# ballast model but I don't think I could find the secure space to load 1000# of stuff below or at the waterline, centrally. By secure I mean if the boat is knocked down, all the stuff does not move.

[a64pilot]

Originally Posted by GTom

Compressor placement is of course reason for further headache. However, there are <45kg/100lbs models around, that can be stored safe in a cabin and placed on board only when needed. Ideal would be an electric compressor (no smoke=can work below deck) but those usually need 2+kW power.

Not doubting you, but do you have a link to one? If there is, I may want one.
Also unless I have been misled, your talking at least 7.5 KW to run an electric compressor, it takes a tremendous amount of energy to compress air to 3000 PSI or more.

I have a 38' IP which are big for their size, with two people and I don't have room for the compressors I have seen

[hamburking]

I had a Pearson 30. I never explored max load capacity, but I did try to keep weight down on my boat. In fact, I usually sailed alone with very little extra "stuff" aside from a 4hp outboard on the stern rail and an avon inflatable stowed below in the quarter berth. I kept the water and waste tanks empty. What I noticed was that the boat was noticeably faster when sailing light, and handled extremely well. With a crew of 4 or 5 people and all their gear, the boat went slower and felt sluggish.

Why do you want to load up your 30 foot boat so much?

[Stumble]

Originally Posted by a64pilot

Not doubting you, but do you have a link to one? If there is, I may want one.
Also unless I have been misled, your talking at least 7.5 KW to run an electric compressor, it takes a tremendous amount of energy to compress air to 3000 PSI or more.

I have a 38' IP which are big for their size, with two people and I don't have room for the compressors I have seen

Nuvair sells the MCH6/3E that may fit. 110lbs, 23 minutes to refill a tank (500-3,000), and draws 2.2kw off of 110v.

[a64pilot]

Originally Posted by Stumble

Nuvair sells the MCH6/3E that may fit. 110lbs, 23 minutes to refill a tank (500-3,000), and draws 2.2kw off of 110v.

Data I can find for it says 28 amps at 110V, is there another?
In theory my 3.5 KW gen is a 30 amp generator and it can make 30 amps, but I wouldn't want to ask it to do it continuously, but 2.2 KW would be easy

[Stumble]

Originally Posted by a64pilot

Data I can find for it says 28 amps at 110V, is there another?
In theory my 3.5 KW gen is a 30 amp generator and it can make 30 amps, but I wouldn't want to ask it to do it continuously, but 2.2 KW would be easy

I believe that it's 28amps at startup but drawn 20 when operating. A 3.5kw is pretty close but it should kick it off if you start it with no load. But I would certainly give them a call to confirm.

[GTom]

Originally Posted by a64pilot

Not doubting you, but do you have a link to one? If there is, I may want one.

Link to the Nuvair/coltri <45kg units, the 3e version provides 3 scfm with 3kW power need:
https://www.nuvair.com/store/mch6-portable.html

Quite slow if you use big tanks but should do the job with a few spare tanks and good scheduling. Faster filling rate comes with proportionally larger wattage and comes with heavier engine/pump. Personally I would never use a compressor which I cannot lift alone.

Originally Posted by hamburking

... With a crew of 4 or 5 people and all their gear, the boat went slower and felt sluggish.

Why do you want to load up your 30 foot boat so much?

I don't have a boat yet, just collecting info if I should lean towards certain designs/models, worst case step up to the 40' category (latter means +$$$, unused in most coastal cruising/non diving scenarios - not to mention wintering).

Originally Posted by bsurvey

crossing to Hawaii on my 30 ft boat with crew of 4 took 14 days, we had food and water left over. I have sail across the pond to HI 4 times
1 to 2 people on deck at all times.
food was freeze dried and heater meals, no way we even came close to 1000 lbs
are yopu putting a wine cellar on board

Hehe, vine cellar is not planned, just 4 full scuba gears with 8 tanks, compressor, food.

[Pete7]

Think I would choose the petrol version for ease of use, but not the coltri model. Had one of those in the diving club and we killed it, stripped it very carefully and rebuilt it slowly but it still didn't run well afterwards. At another club we had the German Bauer, very old and worked hard. It just seemed to keep going with all the abuse a club could throw at it.

Pete

[Don C L]

8 tanks? Whoa. Ok I'd look at a Rawson 30 if it must be 30, or move up to something like a westsail 32. The Rawson has a big cockpit, which may be necessary. I'd also look for a tiller so you can get it out of the way while anchored/diving. But you are really pushing some limits here! You'll need a good big inflatable to dive from and transfer tanks/people to/from IMO.
The Rawson is roomy, but it is a very heavy boat for its waterline. Seaworthy, but I think you'll need a good bit of wind to get her going. Check bluewaterboats.org for other possible designs, I'm having a senor moment on them right now...