How much can I load on my boat.... Necessary knowledge

[Boasun]

I worked out the pounds or tons per inch of immersion for the S/V Rapture.
It is 2.09 tons or 4670.8 pounds per inch of immersion.

Now how was it done.

Displacement / Cube Root of (LWL X Bwl X .76) = TMI or PMI


LWL = Length of Water line
Bwl = Beam of vessel at the water line
.76 = Is a constance for this formula

So the LWL of the Rapture is 32.25 ft, the Beam at the water line is 13.12 ft
and the displacement is 32000 pounds. And using the above formula I came up with the above answer.

My weight is 200#. Weight of possible guests may total 460# overall for people on board is 660#.
Food for a week. 40# per person per day for 7 days is about 1120
personal gear of the people totals about 120#
So I will have about 1900# estimated total and immersion the Rapture about another one half inch or there about.

On the food I might have over estimated, but some of us do enjoy eating and you do need the calories when sailing. Diets are left onshore when boarding a board.

Personal gear? When working off shore... I had to pack about everything needed and that came out to about 60 to 80 pounds... But I was gone for three months and it was winter. So for summer cruise for a week... the guests may bring 30# of gear but may only use about 10# if warm summer nights abound for the cruise.

The fuel & water is figured into the displacement... But if you bring bottled water that goes into grocery stores.

For small boats; read the builders plate carefully. Because everything you add to that boat is part of the Max weight that can be carried. This includes the outboard, fuel, and so forth.

[killarney_sailor]

Not that it invalidates your calculations to any great extent, but 40 lb/person/day is impossible, even it includes beer which it should. Even 20 pounds would be a lot I think.

[Boasun]

Hey, I wrote this before I had breakfast... and was very hungry...
20 pounds per person/per day would be better.
Upon thinking it over. considering on the weight of food I eat per meal... We can go even less and say about 5 to 7 pounds per day per person, including drinks


Note to self: When considering food supplies, don't do it on an empty stomach.

[funjohnson]

Per SailCalculator.com, they show your Hardin 45 at 1536 per inch.

Sail Calculator Pro v3.53 - 2500+ boats

[Tempest]

Originally Posted by Boasun

Hey, I wrote this before I had breakfast... and was very hungry...
20 pounds per person/per day would be better.
Upon thinking it over. considering on the weight of food I eat per meal... We can go even less and say about 5 to 7 pounds per day per person, including drinks


Note to self: When considering food supplies, don't do it on an empty stomach.

Boasun, don't forget that water and water like beverages weigh about 8 lbs per gallon. In warmer weather. One person could easily consume a gallon a day..

[PCP]

Originally Posted by Boasun

..
On the food I might have over estimated, but some of us do enjoy eating and you do need the calories when sailing. Diets are left onshore when boarding a board.

.. So for summer cruise for a week... ....

You mean you take guests for an ocean passage? Here most of the times when you take guests is not for offshore sailing and summer cruising is mostly along the coast or between islands and guests always like to explore small fishing or touristic villages along the shores and like to go for fresh bread and search for some local tasty products, so in the end what I need to carry is not much. On long passages I don't have guests.

It is different with you?

Regards

Paulo

[Harborless]

Went to the Performance Comparison website. What does Motion comfort and Pounds/Inch values mean? How do you interpret the values from high to low or vice versa?
Lastly, is 2.07 a decent capsize number? Just curious!

[Harborless]

I do not mean to Hijack but I plan on living and traveling on my boat and so find this thread very interesting and also important.

I used your values above and worked out the following numbers for my boat:

(6200 lbs displacement)/ Third Square Root of (22.5' LWL * 9.5' BWL * .76) = 38.165 (Units?)

Did I do this correctly? My boat is a PY26 Paceship. I am trying to figure out the max load I can carry safely since I plan on doing a two month trip with four other grown men and supplies. (That makes 5 men total for a weight of about 900 lbs before any other gear or supplies are included.)

[AdamLein]

So what you're saying is, when offering to crew on long passages, I should advertise my 150-lb weight?