planing high pressure floor?

Strecker25

Strecker25

Well-Known Member
SILVER Sponsor
Nov 20, 2014
4,917
Rochester, NY
Boat Info
2002 410DA
Engines
Caterpillar 350HP 3126
So I have a lead on a "used on time" 275 zodiac for a very good price, but it is the roll up floor so unable to plane so I'm on the fence if it makes sense for us.

What's the consensus on the high pressure/inflatable keel units? Are they really capable of planing? I don't want a rib, and whatever we get must be able to be bagged back up and stored below. Most of the time it will just be for messing around and exploring, fishing in shallows, etc.
 
You can plane with an inflatable floor dinghy. I had a ten foot with a 9.9 two stroke that had no issues.


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Zorba said:
You can plane with an inflatable floor dinghy. I had a ten foot with a 9.9 two stroke that had no issues.


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Click to expand...

Cool, good to hear. Do you happen to remember the model?
 
I have a zodiac bag boat with a small outboard and it will not plane. It will go fast enough to get from anchor to a city dock in no time at all. It does get to be a wet ride if you run it wide open. That said, we have taken it out to the beach maybe five miles aways with no issues. It probably goes about 9-10 mph with two adults. Very handy to have because we can stow it out of the way when cruising and let it float behind the boat when using it at anchor.
 
I had a Mercury 310 Airdeck with a Yamaha F9.9. It barely got on a plane with 2 adults and 2 small kids. Squirrelly in any kind of chop because the boat would flex so much in the waves. Boarding it was difficult because of the inflatable floor. That lasted one season then I got a new Zodiac 310 RIB and put the Yamaha on that. What a difference. Got right up on a plane with same load. Easy to board, much drier ride. Top speed around 20 mph with one adult. But I understand why you need a roll up. You will have to get a smaller motor because it was a hassle to mount and dismount that 9.9 even though it "only" weighed 92 pounds. That means you will unlikely be able to plane with a 5hp. Maybe with one adult.
 
I have a west marine php-275 and a Tahatsu 6hp and it will plane with 1 adult and 2 small kids, any more than that and it won't plane.
 
I have a soft floor Zodiac 12.5 foot Hunt Fish. It comes in 2 parts. Each part weight is about 50 pounds. The floor is plywood but the bottom, part in the water is fabric with an inflatable keel. I have 20 HP Merc on it. With 1 person it will do 24knots. Full of gear and people (900 pounds) it will do 20 knots.
 
onthejob said:
I had a Mercury 310 Airdeck with a Yamaha F9.9. It barely got on a plane with 2 adults and 2 small kids. Squirrelly in any kind of chop because the boat would flex so much in the waves. Boarding it was difficult because of the inflatable floor. That lasted one season then I got a new Zodiac 310 RIB and put the Yamaha on that. What a difference. Got right up on a plane with same load. Easy to board, much drier ride. Top speed around 20 mph with one adult. But I understand why you need a roll up. You will have to get a smaller motor because it was a hassle to mount and dismount that 9.9 even though it "only" weighed 92 pounds. That means you will unlikely be able to plane with a 5hp. Maybe with one adult.
Click to expand...

My experience was very similar to this. Keep in mind the 9.9 and 15 horse 2 strokes are usually the same weight.
 
I had both a Mercury 310 Airdeck with 9.9 hp 2 stroke Yamaha and a 340 Airdeck with 15 hp Yamaha 2 stroke. The 340/15 combination planed easily and flew, the 310/9.9 not so much. As I recall, the 310 had significant bow rise before it would plane, sometimes requiring the passenger to move forward, the 340 would have a very slight bow rise and plane almost immediately. I'm guessing this was due the the longer water line length. The two combinations were within 15 pounds of each other and took up the same footprint for storage. I now have Center console rib but storage space or weight is not an issue for me. If I were in your situation I'd go with the 340/15 combination.
 
I had A Mercury 310 Airdeck with 15 hp 4-stroke and it planed with no issues. Keep in mind that the floor needs to be inflated to something like 12 psi which is a real pain.
 
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I have a West Marine brand HPV-350 with a Mercury 9.9 and it planes easily with 2 adults but flexes too much in a chop to really "perform." If you get out in even small chop it just flexes over the crests and bogs down. Flat water, works great. Choppy water, have to take it slow. Before I bought a "real" boat I used it to zip all over the place.

Since we bought our 400DA it's just too big to fit on the platform (over 12' long and 5'8" wide). It's been rolled up in my basement and only used once or twice a season over the past few years. So I'm trying to get rid of it and buy a smaller RIB. I still haven't decided on what size, but I know I'm getting rid of the 350.
 
Strecker - I was in the same situation as yourself about a year ago and wanted a boat that was "portable". I looked at the airfloors but ultimately decided on an Achilles LEX96 (they also have a smaller model). It has a sectional coated ply floor and is quite stable - I can step into it with no problems. It also has a inflatable keel.

I run a Yamaha stroke 6 hp (weighs 27 kgs). It easily planes with me in it and will maintain plane at a reasonable speed just a above cold start on the throttle with just me in it. At full speed it is brisk but can't give you more specific details. I don't find it squirelly. With my wife and daughter it will just plane. I have bought the Maxi Marine lifters and have blind faith that they will allow us to plane with the three of us more easily and at a lower speed when fitted.

In terms of outboards the Yamaha 6 hp and 8 hp are the same motor with different exhaust and carby - so they weight the same at 27 kgs. Ditto the Mercury 6 and 8 hp two stroke models which weigh 1 kg less at 26kgs. Tohatsu who I understand also builds the small Mercury 2 strokes also has it's own 6, 8 and also a 9.8hp version which all weigh 26kgs. So the big 9.8 Tohatsu at 26kgs wins the power to weight ratio based on my research at the time.

At that weight the outboards are reasonably portable and can be installed and removed relatively easily. I looked at these models as they all had 2 cylinder motors compared the the smaller 2 strokes which only had 1 cylinder. The equivalent 4 strokes weighed around the same as the two stroke models but lose a cylinder to keep weight in line with the 2 stroke counterparts.
 
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Thank you all for all that info, I'm going to keep shopping around. I love the idea of the RIB and having it permanently on the swim platform, but the reality is we really don't need that just yet. Our trips are limited to only a few per year, and most of our weekday/weekend boating is close to home in a bay or just floating in the lake. For that reason, I'd like to find a good mix of portability by getting a boat in a bag setup and maybe just starting with a small OB, but have the option to put a bigger motor on it so we can have some fun later on. I'll keep you all posted no matter what we end up with
 
We've had an inflatable keel dinghy in the past and I wouldn't do it again. Of course that was when we had our 30' cruiser and we had a weight limit that we were dealing with. If you could find the lightest RIB you can find and then get a small kicker outboard for it you'll be much happier. Even if you think you won't go far or use it for much, once you have a dinghy you will start to open up new cruising possibilities and activities. Now that we have a dinghy with a center console we're able to go crabbing and explore further than we could have with our old dinghy.

Got with a RIB - you won't regret it.

Sandy
 
Update to this. We purchased a 310 Zodiac inflatable with high pressure air floor mid last season. I have a 69 Johnson 6HP that I ran on it for a while. It served its purpose, tender when needed (rarely) but more of a toy to bomb around the bay or explore skinny water. I used it a bunch to go fishing in the finger lakes and other places I can't take the big boat. Being an air floor, I was able to roll it up and put it in the back seat of my Jetta, engine in the trunk, and go wherever I wanted. I could pump it up in 15 minutes and have it ready to go in 25 total. I put in a few hours of fishing before work a couple times in the fall. I also bought an electric high pressure pump that I can set to auto shut off at certain pressure. Without it pumping up the floor would be impossible.

The motor was enough for just myself and fishing gear. I could plane no problem with just me and I added the maxi marine tabs to help but to be honest I was at the upper limit of that 6HP so they didn't help much. Fast forward to last weekend when I landed a 1980 9.8 Merc 2 stroke and gave it a run. It's a missile now, especially with just me. I was able to plane at barely half throttle with just my wife and I, and this was without the tabs. There is temporary no wake zone for our entire bay right now because of the lake level, but I can't wait to try it out on some flat water.

As far as the davits go, I'm fortunate enough to have a machine shop in the family so we're building some rocker arm style davits this week and should have them on soon. A 310 is going to look ridiculous on the back of our 290 but it will be nice to not have to pull the motor off every time.
 
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