Saturn 385

fordtrbo · 09 September 2018, 00:34

I have a buddy that purchased a new Saturn 385 and is having "buckling" issues, if that is a real word. He has a new Suzuki 20 hp and the boat came with air floors. He has inflated it with his portable battery operated pump to the correct pressures all the way around. What causes it to buckle at times? He has switched pin positions on the motor....not sure what else to tell him. Any ideas? I have a 1997 Zodiac Futura with air floors and I have never experienced this kind of issue.

smallribber · 09 September 2018, 07:34

Once he has pumped up the boat and put it in the water leave it there for 10 or so minutes and pump up the floor a bit more. The cold water reduces the pressure in the air floor

fordtrbo · 09 September 2018, 14:19

Thanks for the information, I will pass that along to him. Hopefully that will fix his problem.

Sinistre1 · 09 September 2018, 22:02

Agreed. I have their 365 model and you will DEFINITELY get that action when the floor is anything but fully/ properly inflated. Even then you will still get a rolling sensation under foot if the wave crests are spaced apart just so. Nature of the beast. The speed of assembly is traded off for a little bit of rigidity.

Fenlander · 09 September 2018, 22:06

>>> Even then you will still get a rolling sensation under foot if the wave crests are spaced apart just so. Nature of the beast. The speed of assembly is traded off for a little bit of rigidity.

Yep that was broadly what I was going to add. Of course make the pressure check a few minutes after it's been in the water but then if it is still less than rigid accept that's just how they are.

It's very hard to make flat air floors that are 100% stiff once the size creeps towards 4m.

Chopperbill · 11 September 2018, 16:35

I have a Saturn 365. I fought the same problem for a year. This is taken from the Boats to go Saturn web site.
“ It is not necessary to have an air pressure gauge to inflate Saturn boats. The boat tubes are equipped with Safety valves that will prevent over-inflation. In general, when you feel that boat tubes/floor are hard to the touch, and it becomes difficult to pump any more air in, that means that the boat is ready. However, if you are using a high-pressure electric air pump, please use below guidelines to avoid boat over-inflation and consequential damage.”
I was using there max rated pressures. I called there web site because I was not happy with the performance. The guy insisted that I use a hand pump and fill until it was hard. I filled it to the max pressure and then checked the “hardness”. The keel felt like a sponge. I filled it until it was firm and pumped the floor up another pound or two. The difference was like night and day. It planned much better and done away with the bending feeling. It’s worked great the last couple of years with no problems.

fordtrbo · 22 September 2018, 02:21

Thanks Chopperbill, He has yet to get back out on the pond but I will pass this info on. Interesting since I owned an air floor 1997 Zodiac Futura and never experienced the "rodeo cowboy bucking". Must be the price difference, quality etc. My 380 Futura was made in France (I believe) vs China.............

yowsa52 · 10 November 2018, 21:40

Thanks Chopperbill. My SC385 suffers similar. I will check keel and floor pressures and make sure keel is fully hard. Floor may also lose pressure when dumped to the water.

yowsa52 · 10 November 2018, 23:27

Quote:

Originally Posted by fordtrbo

My 380 Futura was made in France (I believe) vs China.............

Korea and now some in Vietnam.

Limecc · 11 November 2018, 01:24

Others have said it already - it's the nature of the beast. Over 3.8m with 20hp carrying 4 adults and plenty of weight it's going to flex and sometimes badly. Some designs are better or worse.

I wouldn't feel comfortable overpressurizing personally. 1- I don't know how they would prove it but it may void any warranty claim. 2- The relief valves are not there to set the pressure they are there to prevent catastrophic failure. I wonder if anyone's had a joint go on an older boat where the glue is breaking down?

smallribber · 11 November 2018, 08:05

Make sure the floor pressure is up and pump it up again once in the water as the cold reduces the pressure in the floor

Sinistre1 · 22 November 2018, 19:14

Yes be extra careful on over pressuring. The relief valve people are mentioning is only on the front chamber of the Saturns. Smart placement though. It helps to equalize all of the three main chambers (think hull) by dumping pressure in that one chamber you effectively release some pressure from all three (has to do with the baffles, etc). That said.. the floor does NOT have such protection so you overpressurize at your own risk. Having said all that... I ALWAYS overpressurize my 365 (at my own risk) once you pass 10psi every extra one really makes a huge difference in the floors performance.. conversely when you get on the water, or if you used an electric pump which will be pumping air that is warmer than ambient.. you WILL get cooling and you will lose some pressure... So, fill up... get on the water and let the boat stabilize it's temps... then fill up again at LEAST to the max pressure... maybe a lil more if you have the stones for it.

Things to be mindful of.. since the floor does NOT have overpressure release mechanism. If you get off the water on a hot day, release a little pressure right away. The pressure will rise while sitting in the sun and not being cooled by water temps. Also found this out the hard way, if you DO overpressurize, be very mindful to release the air slowly when you are done for the day and packing up. The overpressure will cause the Naru valve seal to "blow out" if you just crank it to full open. Do it enough and you will be changing the valve or suffering with valve leaks.

I never go out with more than one or exceedingly rarely two people so the floor issues may change dramatically with additional weight and I can't speak to that. I do know that the max pressure they list has a safety margin built in... which takes away from the performance margin... Nothing for free

yowsa52 · 22 November 2018, 22:55

Tomorrow and Saturday will be test day on a small lake. I have a couple of electric pumps and a small 20amp motorcycle battery and a gauge. I have never been on the boat by myself so this should be interesting. I will be using a tiller extension to get the weight more centered in the boat.
I usually put in 3.5 in the tubes, 6psi in the keel and have put as much as 13psi in the floor.
The last time I took the boat out, a couple of weeks ago, was in the Gulf of Mexico. It was a rough weekend and did not get it on plane much so don't remember what the keel was doing.
Thanks for the good procedure regarding letting some pressure out when loading. I trailer the boat.
I will update this thread after this weekend.

Chopperbill · 23 November 2018, 16:04

Quote:

Originally Posted by yowsa52

Tomorrow and Saturday will be test day on a small lake. I have a couple of electric pumps and a small 20amp motorcycle battery and a gauge. I have never been on the boat by myself so this should be interesting. I will be using a tiller extension to get the weight more centered in the boat.
I usually put in 3.5 in the tubes, 6psi in the keel and have put as much as 13psi in the floor.
The last time I took the boat out, a couple of weeks ago, was in the Gulf of Mexico. It was a rough weekend and did not get it on plane much so don't remember what the keel was doing.
Thanks for the good procedure regarding letting some pressure out when loading. I trailer the boat.
I will update this thread after this weekend.

6 psi in my keel is soft as a sponge. I fill “hard to the touch” like I was told on the phone. Cured my planning problems.

yowsa52 · 24 November 2018, 01:54

Quote:

Originally Posted by Chopperbill

6 psi in my keel is soft as a sponge. I fill “hard to the touch” like I was told on the phone. Cured my planning problems.

After running today. 6psi for keel is good and 12psi for floor. Feels solid. I will put a little more in keel for tomorrow cuz at my top speed of 22mph boat feels a little squirrely at times.

Sinistre1 · 28 November 2018, 02:03

Sounds about right.. the closer you get to the "filled to ragged edge" pressures the more squirrelly it will get.. What starts to happen (to the best of my guessing), is you start to approach a truer hard hull level of performance.. on an insanely light boat... it literally starts to skim the surface... like a skipping stone... hyperbole aside, it really does start to perform way better but it also becomes more flighty. Ive gotten mine up to a GPS verified 25.6mph. Everything was pumped up as hard as I dare, the motor was lifted up almost an inch from fully seated on transom and it was just me and some fuel... in a container of course, Lol. Poin is I was TERRIFIED!!!! It felt like it was skipping over some very small close chop (almost like the offshore tunnel racers, and Every couple of bumps it would land and try to hook,,, I backed off pretty quickly. The oddest thing is at 24 mph (engine fully seated max speed) it feels totally controlled and on rails. The above is with the 20hp zuki and a 12 pitch prop (it's usually only me on the boat so I traded a killer hole shot for about an extra 1.5mph)

yowsa52 · 28 November 2018, 02:31

Quote:

Originally Posted by Sinistre1

Sounds about right.. the closer you get to the "filled to ragged edge" pressures the more squirrelly it will get.. What starts to happen (to the best of my guessing), is you start to approach a truer hard hull level of performance.. on an insanely light boat... it literally starts to skim the surface... like a skipping stone... hyperbole aside, it really does start to perform way better but it also becomes more flighty. Ive gotten mine up to a GPS verified 25.6mph. Everything was pumped up as hard as I dare, the motor was lifted up almost an inch from fully seated on transom and it was just me and some fuel... in a container of course, Lol. Poin is I was TERRIFIED!!!! It felt like it was skipping over some very small close chop (almost like the offshore tunnel racers, and Every couple of bumps it would land and try to hook,,, I backed off pretty quickly. The oddest thing is at 24 mph (engine fully seated max speed) it feels totally controlled and on rails. The above is with the 20hp zuki and a 12 pitch prop (it's usually only me on the boat so I traded a killer hole shot for about an extra 1.5mph)

I have only checked RPM with a pretty good phone app (pay app). By myself I used a tiller extension, 30". When i sat back by the motor it was very squirrely. I am sure the motor could do better up about one inch higher as I usually have another person in the boat. My prop is the stock 9.5 inch 10p and if I remember it was getting about 5500 rpm. It is a newer Tohatsu 20hp EFI. Running two and half hours, much of it WOT, I used a little more than a gallon.
I have the motor on the next to last hole for motor tilt. I should be able to coax a few more MPH adjusting things correctly.
Overall the boat is fine but being of the male persuasion I want to go as fast as it can go with the setup I am using. Of course. I read one fellow got 33MPH on a SD385 with a 30hp and his two kids. ha,ha.

Chopperbill · 28 November 2018, 15:25

100% of my boating is on a river. You can’t believe what I’ve been through as the boat is different if going up or down river. Plus the speed of the river is different depending how much they are releasing from the damn. Add dozens of speed boats going by, some approaching 100 mph! Those are the days I stay off the river. I’ve have lived to compromise with my boat and find 15 - 20 mph is more comfortable even though it will do 25.

yowsa52 · 28 November 2018, 15:37

Compromise. I think the Company realizes their boats placarded for more horsepower they always recommend less for safety and comfort Hard to beat for light maneuverable boat.
This weekend I will raise motor and attempt to trim for two people
We don’t have much in large rivers here in S Texas . It is the Gulf or lakes.

office888 · 28 November 2018, 16:45

Quote:

Originally Posted by Limecc

Others have said it already - it's the nature of the beast. Over 3.8m with 20hp carrying 4 adults and plenty of weight it's going to flex and sometimes badly. Some designs are better or worse.

I wouldn't feel comfortable overpressurizing personally. 1- I don't know how they would prove it but it may void any warranty claim. 2- The relief valves are not there to set the pressure they are there to prevent catastrophic failure. I wonder if anyone's had a joint go on an older boat where the glue is breaking down?

Back when I was doing repairs, under inflation damage was one of my biggest dependable sources of “high value” repairs. I was the only person in a 3 hour drive radius whom could do them, and the average bill for a partial cone blowout was about $500 USD.

In my years repairing inflatables, I have only repaired 3 boats with overpressure damage. Two blew due to inflation with SCBA. One zippered open due to a weak seam to begin with (CSM “Hypalon” with poor bond strength, the adhesive only adhered to the CR backside of the seam and not the CSM topcoating it was bonded to).