Building a Corsair CR13

[Brocky]

I guess when I get out on the water I can fiddle around with all those settings and work out what suits me.

[Jaysen]

The only problem with higher thrust will be weight added due to motor size and battery. Maybe 20lbs. The depth will be inconsequential as it will always change as you mount/dismount/adjust (someone sitting port or starbord, cooler location, etc). also, you will be mounting this thing off keel so ... yeah. figure it out when you are on the water.

For the most part, unless you are going to be flying these in a race class, don't worry about anything but weight for now. The 'how low" should be "transom + prop + some more". The thrust should be "enough to overcome current maybe". The rest will have to be figured out once you are sitting on the water asking "now how do i get out of this mess?"

That last part is experience.

[VT_Jeff]

The thrust should be "enough to overcome current maybe".

Agree on the maybe. I suspect you won't get enough thrust to get the boat to plane, which means you'll be limited to hull speed, which means you can only overcome current that is less than hull speed, which is hopefully the only current you'll encounter. But yeah, I would ideally want enough thrust to push at hull speed with an expected load into a head wind/chop, if only to get on a hook, on a dock, on a trailer, off a lee shore, etc when needed.

BTW, Good to practice all those without motor, so if you do find yourself needing to do any of them with a dead battery, it won't be your first time. When I first got my C&C 29 I would practice getting off an anchor on a lee shore under sail alone, motor running just in case. The confidence it provided in invaluable. Not that I plan on anchoring on a lee shore, but wind can change.

The rest will have to be figured out once you are sitting on the water asking "now how do I get out of this mess?"

That last part is experience.

A story about a drawbridge comes to mind here.

[Jaysen]

A story about a drawbridge comes to mind here.

I still get reminded of that everytime I go to the marina. Every. Damn. Time.

[Brocky]

If I still have any money left after building this boat I will buy a Lithium battery. Even a 50ah deep cycle (probably the bare minimum) is nearly 20kg, whereas the Lithium is about a third of that. The motor will definitely be offset, so I suppose where I sit will make a difference too eh!
I don't think this is a planing hull, and anyway I just want to get home when there is no wind. Wind and current when coming into shore requires some planning first. I suppose the higher thrust motors have a bigger angle on the propeller to take advantage of the increased thrust, the Watersnake goes from a 2 blade to a 3 blade propeller which should help, I think. I agree Jeff about practicing without a motor, I have got myself in all sorts of difficulties trying to come into shore with a number of small boats I've sailed over the years. No major damage however, except to my pride.
A drawbridge! Now that sounds like an interesting tale. Or should it be consigned to history and never mentioned again?

[Jaysen]

Let's just say, it started with a 800mi (1800km) drive (one way) to get a 15yr old 2 stroke motor for a 40yr old boat and ended with an communciation sequence of "if your mast is 32' and that part of the bridge is only 30' tall and doesn't go up ... you may need to deploy an anchor REALLY FAST!"

There was current, some very loud eye rolls from a wife, a dog who tried to help pull start the afore mentioned motor, and a pumpout boat from the marina involved as well.

To be honest, the story need me to go get some rum before I can tell it well (get, open, embibe, get in the mood with good company and guitar picking... all of which Jeff makes easy).

[Brocky]

Oh dear, a bit cryptic but I get the general idea. The fact that you needed the services of a pump out boat suggests that it didn't end well. I have a mate who thought he could squeeze under a bridge at low tide, but only suffered a damaged mast top, and a great story as well.