A secured loan (the RV, boat, or land is collateral) carries a lower rate because the lender can repossess; an unsecured loan costs more but puts no specific asset at risk.
Secured terms run longer, which lowers payments but raises total interest and risks negative equity on fast-depreciating assets.
Compare the all-in cost and the downside: unsecured may be worth the higher rate if you want to avoid tying up the asset.
Try it: more on secured unsecured loans big, see assetloancalculator.com.