The fastest way is to use the same oil drain pump used for the dipstick but hook it to the end of the oil drain hose from the pan. Always going against gravity will not get all the old motor oil out, especially if you are sucking it out from the top of the dipstick.

Yes I just need to know if the hoses are going to work on my boat first lol

I tried a thin hose down dipstick tube. I sucked oil so slow ended up burning up 2 pumps before I gave up. Get a hose that fits over the outside of dipstick. I keep a hose clamp and a nut runner in my oil change pump box. Tighten the hose clamp on the hose after it is slipped over tube. It sucks way way better than the thin hose.

1st question will be are you planning to install these while the motors are in the boat? The bilge pumps are right below the drains and that with the abundance of working space doesn't exactly make this a walk in the park. It is reachable though if you are a small person. I can wiggle down under the pumps and lay down on the floor and reach my drains, but not something you wanna do for each oil change. :) If you do/can install hoses, make them long enough so you can route them up front and just use a small pump connected the hose to pump the oil out, then cap the hose when done and attach the hose to a bracket to prevent it from flopping around. A pump connected to a drain hose will suck the oil out in a matter of few seconds.

I would install them with engines in the boat myself.. I'm good at wiggling lol. So you don't run them out the back then I'm assuming? Is it because it is not possible or just your preference? Sounds like it may be just as easy to do the dipstick method if I have to climb in and connect stuff and use pumps anyways. I was hoping to get two of the Merc kits that come with hoses and bilge drain plugs with little wires attached to the hoses so when you pulled the bilge plug you could grab the wire and fish the attached hose out one at a time. I wasn't sure there was enough room between the stringer and the bilge drain though since I haven't "wiggled" myself back there far enough to actually see.