How can I get a home equity loan on a manufactured home?

Unfortunately, manufactured homes (aka mobile homes although they are rarely moved after their initial siting) are usually considered by banks to be on par with unsecured loans:

• you often don’t own the land beneath the building
• the building is often of very cheap quality
• finding a buyer can be difficult and often only for much less than the initial purchase
• people who live in manufactured homes are often in precarious financial straits to begin with

A manufactured home is (usually) not a good investment as it will never appreciate in value — and the situation is much worse if you don’t own the land beneath it as then you are not in control of the rent charged for the land and hookups, so you cannot easily forecast whether it’ll be better than renting an apartment (which you would be able to easily leave if the rent went up).

This is why banks are loathe to lend. That said 42% is usurious. You might try your local credit union but you’re essentially getting an unsecured loan so you’ll get the worst rate.