With 3 kids and a dog going to the beach always ends with enough sand to fill a sandbox on the front of the boat. Even with two tubs to rinse your feet, dog just refuses to use them. Thinking about t ing into the water slide feed with a t valve, that way I don't have to add another pump. Putting a hose hook up on the deck in the back of the boat and using one of the flex hose you see on tv. I'm not looking to pressure wash the front deck, just wash the sand off. Has any one tried one of the hoses? I like the look of them for there size and ease of storage.
The flex hose itself should work fine. The real issue will be how much pressure you have by the time you get to your nozzle. On my boat, the lakewater pickup is at about midship. Water then goes to the back of the boat to reach the slide. A water line hooked to a tee fitting at the slide would then have to go the length of the boat before reaching the flex hose at the front of the boat. While you aren't looking for a pressure washer type of flow, there may not be much more than a tickle by the time you take water on a long journey from your pump.
Having said all that, what do you have to lose by hooking it up? If you hook it up and it doesn't work, you will have the advantage of having your plumbing in place to hood up a dedicated washdown pump. I think I'd give it a try but be prepared to add a washdown pump if need be.