Boat Upgrade: Inflatable Hot Tub on a Bayliner 4788

Before we bought our boat Y-Not in 2017, we of course deeply researched the Bayliner 4788 model.

And we were very intrigued when we found posts from a few owners who had added hot tubs to the flybridge successfully.

We love getting in hot water – would we be able to someday add a hot tub to our boat?

Researching how to add a hot tub has been on our “someday” projects list ever since. Particularly since our boat was never setup to carry a tender & crane on the top deck like most Bayliners come stock – we had a lot of open space, and extra carry capacity, to turn our flybridge into a spa.

All it took was a pandemic keeping us homebased for a chilly winter season to move forward with the plan. Well, and maybe a little wine before spontaneously clicking the “buy” button on an inflatable hot tub last year?

So here it is, our report on bringing a hot tub aboard, what we got, how we set it up and how it’s been working out.

Come join us in the hot tub!

Aleko Inflatable Oval Hot Tub

Finding a hot tub small enough to fit in the limited space we had on deck was a challenge, and it really came down to just one option that was actually available and in stock to buy.

We purchased an Aleko Inflatible 2-person Oval Hot Tub on Amazon (affiliate link).  Priced right around $500 when we ordered last year, it kept going in and out of stock.

While were visiting Chris’ parents for Thanksgiving, I spotted it come back in stock – and they asked if it could be an early Christmas present, and thus we clicked the buy button to see if this thing would actually work out for us.

We honestly didn’t have very high expectations from reading the reviews. And we figured it if was good enough for a couple months to help relieve the stress of working way too many hours, the pandemic and the general unrest of the world – it was worth it.

The tub runs off 110v, so no special wiring was needed. The air pump that provides the bubbles also is setup to inflate the tub – super quick and easy to get setup. It takes about 24-hours for the water to get up to temperatures, which is annoying when you just want to soak.

But once it’s up to temperature, it stays there pretty easily. And, it can go as high as 107 degree.

For fit, we honestly thought it was going to be bigger and we’d have to remove the sliding dining table the original owner had installed on our flybridge – but magically, the tub fits perfectly on our deck with no modifications needed. It’s really like it was made just for our boat.

Ok, so now we know you’ll have some questions – so let’s address them.

What About the Weight?

The tub is sized to hold 120-140 gallons of water, and we fill only to 120 to keep the weight as low as possible.

And 8.3 pounds per gallon, that is 996 pounds.

But the things that made us feel comfortable setting this up on the top deck include:

• The flybridge of the Bayliner 4788 was designed to hold a crane and dinghy to be lowered into the water, but ours was never setup this way. This are was designed to hold extra weight (maybe not this much.. but..).
• The Bayliner 4788 was designed to be a ‘party boat’, holding about 20 people. There’s only two of us.
• This area of the deck is right over the back wall of the salon – a supporting wall right under it.
• We had already read of other owners of our model of boat who had successfully put hot tubs in this area.

That’s not to say we’re not concerned about being so top weight heavy.

Thus we intend to only have water in the tub when we’re at dock, anchor or traveling in super protected waters where we’re unlikely to encounter much wave action. If we’re making an open water crossing (such as to the Bahamas), passing off shore or going through areas known for sloppy conditions – we’re draining the tub and just not taking the risk.

And yes, the weight of the tub on the port aft side of the boat does cause a lean.

We’ve balanced that out by shifting fuel out of the port tank into the starboard, and making sure our fresh water tank in the bow is full (we intend to also add more anchor chain in the future, which will help keep us more bow down.)

With the tub onboard, we’ve traveled the length of the St. Johns River from Sanford to Jacksonville and back (200 miles) – and noticed no issues or changes in performance.

We were able to get up on plane, handling has been great and we’re not concerned.

Of course, we anticipate that there is likely some hit to fuel economy. But if you own a boat, ‘fuel economy’ is a relative term anyway.

What About Soaking While At Anchor?

Soaking in the tub at dock is nice and all (and we’ve been blessed with relative privacy at our marina in Sanford).

But the true beauty is taking our boat to a secluded anchorage and going au natural.

But at anchor means no shore power. And heat needs power.

When we first got the tub, we would super heat the water before leaving dock… and then we just heated the tub off our lithium batteries and/or generator. Since it only comes up a degree or two an hour, that’s a lot of power draw.

We hate to hear the drone of the generator running for hours just to keep our water hot, we needed another answer.

Since we already have a marine grade propane tank on board for our grill, we decided on a propane solution. Chris dove into research, and came up with a propane auxiliary heating system that can heat the tub in just an hour, and which can even be controlled by Siri on our watches!

Propane Aux Heat System Parts List:

• Propane Water Heater – Camplux 5L Outdoor Portable Water Heater – 1.32 GPM Tankless Propane Gas Water Heater
• Submersible Pump (for propane heater loop) – Superior Pump 91014 1/4 HP High Flow Thermoplastic Utility Pump
• Sediment Filter – LOVHO Sediment Filter Attachment
• Braided Clear PVC Vinyl Tubing – 1/2″ ID x 3/4″ OD – We used 25’ of hose.
• Misc Hardware – 3 Sets Brass 1/2″ Garden Hose Mender – Comes with stainless clamps, and lets us turn the tubing into a hose that mates with the pump, filter, and heater.
• Siri Remote Control – meross Outdoor Smart Plug – Compatible with Apple HomeKit, toggles the power on/off for the submersible pump.

The small and affordable portable Camplux propane water heater is designed to allow hot outdoor showers while camping. It uses two D batteries to control the igniter, and it comes on automatically when it detects water flowing through its inlet.

We tried several pumps to run water through the propane heater, and ended up settling on a 1/4 HP submersible that we can easily lift out of the hot tub and set aside when it is not needed. This size was strong enough to reliably trigger the heater’s auto-on function – since the heater is activated by water pressure a low-pressure pump will not work.

And we discovered – non-submersible pumps were WAY too loud!

TIP: The water heater has a tiny mesh screen on the water inlet. We removed this screen since it was clogging with gunk too frequently, causing the hot water not to engage. Instead, we rely on a larger external sediment filter.

There is no thermostat on the heater – but it will shut down if the water exceeds its max temperature. To control how hot the tub gets, we set a timer and only run the pump as long as is needed.

Tutorials:

We found these links researching this project, and got some good ideas that helped.

https://www.stocktankpool.net/propane-stock-tank-hot-tub

https://www.instructables.com/Portable-Water-Heater-for-a-Hot-Tub-or-Pool/ 

Opinions and Thoughts

For such an affordable solution, we’re absolutely loving the hot tub.

We filmed the above video in June on our St. Johns River cruise and used the tub nearly every night for the first half of 2021. It’s held up pretty well, with just a few air leaks that have required patching.

But as discussed in the video – we’ve found the ‘brains’ of the tub’s controls to be very stupid, without much control other than setting a temperature and turning the air bubbles on/off.

Most annoyingly – the tub has a filter alarm to remind you to clean/change the filter every 168 hours (aka 7 days). However there’s no way to reset the alarm if you clean the filter in advance, or to turn it off entirely. So no matter what you do – every 168 hours of usage your hot tub will start beeping, even if that happens in the middle of the night.

And the tub has no timers or way to just have the filter run a few hours a day – it’s either on all the time, or you have to manually turn it on/off. Even using an external timer at the plug won’t work – as the filter pump doesn’t automatically come on when the power does.

This stupid filter alarm make it a pain if we leave the boat for a while, such us on a few day van excursion – if we want to leave the water warm so we can soak when we get back.

Because we can’t disable the alarm – we typically will drain the tub and refill when we get back, and often initially heat with propane if we want an immediate soak. Trying to time the filter cycle with ‘life’ isn’t feasible, and we don’t want our neighbors having to deal with an alarm going off while we’re away.

We really wish Aleko would make this exact same design two-person tub with higher quality materials (so less small holes to patch), and a much better brain.

But overall.. we consider this upgrade a huge WIN!

The whole system couldn’t be simpler – and the water heater, hoses, pump, and the entire hot tub itself packs away into one of the lazarette chambers in our cockpit for storage when we are away from the boat and don’t want everything out. Such as it is now that we’re on a cross country van trip and the boat is stored back in Florida.

---

2024 Update: After 4 years of the Aleko on deck and having to repair the same leak over and over again – decided to get a new hot tub. This time, we went with the very similar one from RelxTime. Same dimensions, but it has better insulation on the lid, built in padded seats and two filters.   Oh, and it’s blue.

Our propane heater was also looking rough, so for safety we got a new one as well.