Tag Archives: Gumotex Solar 410C

Gumotex Solar 410C – the new Sunny

Gumotex Solar 410C – from 2017 it became the Solar 3
410cThe Solar 410C was a step up from the short-lived, fixed-seat Solar 2 (below). The price in the UK with two seats and a skeg was £470.
It became for all intents and purposes the new Sunny, because the old discontinued 405 Solar and Solar 2 were usefully long touring boats ruined with terrible seat designs: either the original space-wasting thwarts (at least they were replaceable) or worse still, Helios-style fixed seats in the half-coat (Lite Pack) Solar 2 – the pits!
Luckily, the Solar 410 ‘C’ (for ‘Convertible’) has two or even three seats which can be removed and one re-installed the other way round to make a big, single seat kayak with lots of room for stuff – nice. You 410prvalso get adjustable footrest pads (see here for a lighter and simpler idea), a bit of a half-arsed cargo net in the back, and I see a floor PRV in the video below (still, right). Gumotex never seem to mention this useful feature, but of them I am a big fan.
If not included, the black plastic skeg might be extra (and is worth getting). On the 410C you don’t need a skeg-mounting patch at both ends because unlike a Sunny, you simply move the seats forward or back on the D-rings to change configurations, not turn them the other way. In the unlikely event your 410C doesn’t have a skeg patch, it’s not so hard to glue one on.

The stats for the Solar 410C are 4.1m long (Sunny 3.85m); 80cm wide (Sunny 77cm), weight 17kg (Sunny 16kg) and payload no less than 270 kilos (Sunny 180kg). With pressure still at 0.2 bar/3psi, that looks to be quite a jump in payload for just a little extra volume. If you can imagine three of me sat in the new Solar, that equals 270 kilos – the slightest wave will surely swamp the boat.
But one thing I do wonder with a 410C (and why I got a Grabner instead, even at nearly twice the price), is that with my weight I suspect the longer hull would flex even more than the Sunny. This was why I moved on from the Sunny after many years, although here I discuss ways of getting around that flaw.

Old Gumotex Solar 405/ Solar 2
The original, pre-2007 Solar 405 (left) was similar to a Sunny of the time with a usefully longer payload or tandem paddling. But it used space-wasting thwarts (fat air cushions) for seats. For that reason a Sunny was always better solo touring choice at the time>
The post 2007 ‘Solar 2s’ (right) became even less versatile: horrible fixed seats like the Twist and Helios may give great support, but along with fixed footrests it all means it can’t be set up optimally for solo paddling without chopping it all out.
As on all post-2007 Solars for a while, only the outer wet surfaces were coated, and then the Solar 2 was dropped in favour of the broadly similar but more popular Sunny MkIII, the semi-decked 3.8-metre Helios II (also with fixed seats and decking) or even the shorter Twist I. By 2013 the 410C set things straight again.

Gumotex Solar 300 improvements

gumsolarstacThey don’t make the Solar 300 anymore – it’s been superseded by the lighter Twists, although the similar full-coat, white-water Safari is still made All these Gumboats and a few others may benefit from the footrest mod as described below, as might the 410C and Seawave which both use a similarly mushy footrest pillow.
Our Solar dates from 2006 and although (or because) it doesn’t get used much it still looks like new. And it’s lost no air to speak of lying in the garden for over a month (can’t say the same for my K40).
But the seat/footrest arrangement is poor, like all Gumos from that era. The seat pivots at the right angle base as you lean on it, because the top edge is attached to the bottom edge instead of the actual boat, like any sensible IK. You lean back, it lifts up – no good. I messed around a lot with my old Sunny before I got smart and simply glued some D-rings onto the top of the hull sides, which Gumo started doing soon after. This way when you lean back or brace against the footrest, you’re locked to the boat and so get more drive.
The pillow thwart footrest is OK, but I ditched that at the same time on my Sunny to use a small Otter box. For the Solar, the g-friend is short and can’t reach the footrest pillow even set right back.
I glued on a pair of big D-rings with Aquaseal (hopefully bonding PVC D-rings to the Nitrilon hull) to the top of the hull sides to provide a fixed point to tension the seat back. And I removed the footrest pillow and replaced it with a bit of sawn-off four-inch drain pipe, tapeing the pipe ends to limit any rubbing against the hull. The seat straps were sewn into a loop and clipped to the D-rings.
Hopefully this mod will improve bracing in the Solar – it’s the bane of all IKs (and SoTs for that matter) which without bracing are like paddling a log. This ought to improve response, giving you something to drive off. The footrest (the tape goes through a slot under the pipe) can easily be moved, even when inflated. I suspect it may well transform the Solar which is a nippy IK. The next step would be to fit thigh straps as found on the current Safari – then you can do cool stuff like this – but for the use our Solar gets, the current improvement will do.
gumoldnewskegRecently I also glued on the later style skeg patch (left) to take the plastic fin. No more faffing about with butterfly nuts and bolts and bits of bent alloy. The patch costs £12 and so does the skeg, which I also fitted to my Grabner Amigo.

Inflatable kayak valves and PRVs

Pumps are here
Installing high-pressure PRVs
Updated Summer 2020

The best inflation valves for an inflatable packboat aren’t the simple bungs you find on an airbed or an old Semperit. Nor the twist valves off a Feathercraft Java or an old Alpacka.
What you want are one-way valves like the high-pressure ones on white water rafts, pictured right and copied by many. Like a car-tyre valve, one-way operation as well as a secure seal are the key, so what pumps in doesn’t push back or escape when you remove the inflation hose.


With proper IKs valves, pushing the button down and turning clockwise locks the valve open to release air. For pumping up, push lightly and turn anticlockwise so it springs back up to seal. This closed ‘button up’ position is the best way to transport an IK as the valve mechanism is less vulnerable to damage. To lose a little pressure (say, the boat is getting hot in the sun) just jab the valve core button, same as on a car tyre.
Post-2010 Gumotex valves use ‘push-push’ valves (left). I always make sure I refit the cap seal straight away to keep grit or water out.


I’ve found these valves reliable on all my IKs, although this Gumotex 410C owner didn’t. Once in a while – or after the boat is new – you may want to check the valve is screwed tight against the fabric with the valve spanner, right. They’re useful too for removing the valve (or a PRV; see below) should it play up.

When it comes to inserting the inflation hose, one-way IK valves can take simple push-fit adaptors as shown below left; just shove the adaptor in and it sort of stays in place while pumping. It looks cheap but on a Gumotex at least, works fine. With higher-pressure boats like Grabners and Incepts and some Gumotii, you’re better off using a bayonet fitting (below right) so it won’t pop off as pressure builds.

Low-pressure valves for packrafts

Screw-cap Boston valves  are used on cheaper IKs as well as slackrafts and packrafts. They have two caps: the main one unscrewed (below left) to dump the air, and a square cap to access the one-way valve to top off a boat (middle). These are low-pressure valves using a simple soft rubber ‘mushroom’ on a stem (below right) which is fine on a boat you top off by mouth, not a pump – ie: packrafts not proper IKs. With a packraft, the one-way valve eliminates the need for a separate top-up valve which means one less thing to leak or malfunction. Most packrafts use these now.

Pressure release valves (PRV) for IKs

I’ve learned to be careful not let an IK get too hot when out of the water. On a warm day you can feel the side tubes tighten like a drum. This of course happens to be good for paddling efficiency but isn’t good for the glued seams or an I-beam floor. Below warnings from the Grabner manuals.


The floor tube on my old Sunny had a pressure release valve – oddly it’s something never mentioned in the specs, even on current Gumboats. It’s there to protect the I-beam floor which could tear apart inside under pressure (I-beam floors explained here).
The valve is set at a certain pressure to purge when the air inside heats up and expands. It means an IK can feel a bit soft in the cool morning following a hot day; don’t worry, you don’t have a leak.
The handy thing with a PRV is that it makes a good guide to how hard you ought to pump up the rest of the boat without a pressure gauge. At whatever pump effort the valve starts hissing, that’s the same or a-bit-more pressure to put in the side tubes which may not have PRVs.

The air in an IK can also get cooled, for example when pumping up on a hot day and then putting in a cool river. Because you want the boat to be as rigid as possible, after inflation it’s worth topping up once the boat is in the water; splashing helps cool the sides. Topping up or tempering optimises rigidity and with long 2psi boats you need all the rigidity you can get. In the same way, pumping up your boat in way sub-freezing temps and then putting it on water which actually ‘heat’ it up, though this is a much less likely scenario.

A PRV purging
K40 PRV leaking from the sides not through the valve.
Needs tightening with special tool.

My higher pressure Incept K40 had PRVs on all chambers which meant you could confidently leave it in the baking sun and it would safely purge then feel a bit soft once cooled down back in the water. Picture above: Incept PRV test with the protective cap removed and purging correctly through the centre.
Below: a PRV being resealed after leaking from the edges (left). This was because I failed to check their tightness after buying the boat, as recommended by the manufacturer. My Gumotii never needed such tightening or checking in years ownership.
I ended up also fitting side tube PRVs to my Gumotex Seawave to run higher pressures.


Oddly, my Grabner Amigo didn’t have any PRVs at all and neither do the latest Holiday models and a few others, even though all run higher than normal 0.3-bar pressures. One presumes Grabner are confident in their vulcanised construction to think they’re not needed, though see the warning above.
If your pump has no gauge Grabner do PRVs to fit on the hose (left) which purge at 0.3 bar, so dispensing with faffing about with a handheld pressure gauge.