Depends on the size and seating capacity of the lifeboat. And there's also a limit as to how much weight a lifeboat can hold
it can't hold very much weight
Lifeboat (1944)
For each person in the lifeboat: food - 0,5kg and water - 3kg.
It depends on the size of the lifeboat, the amount of water it displaces, and how heavy the people are.
100 people
20 times its weight in liquid
112lbs
it can hold as much weight as it can handle
Lifeboat - 1944
There is effectively no limit to the amount of weight that aluminum can hold, if you use enough aluminum.
A triangle is a shape. How much weight a triangularly shaped object could hold would depend on the nature of the object.