Anyone own a Gemini GRX 420

[ThundercatRob]

Just wondering if anyone on here owns a Gemini GRX 420?

I picked a used one up a month or so back. Be interested to speak to any owners, as I know they are a bit niche.

[ThundercatRob]

[RickW]

Would love to hear your thoughts was seriously tempted wit the idea of the GRX or Surfcat for beach launched fun. As you say not many around

[69cmw]

I have a Surfcat [emoji41]

[ThundercatRob]

Originally Posted by RickW

Would love to hear your thoughts was seriously tempted wit the idea of the GRX or Surfcat for beach launched fun. As you say not many around

Thanks, i will let you know once i get a chance to use it. Its currently stored in Lincolnshire, and I'm based in Surrey which is annoying. I will hopefully bring it back soon. Needs a bit of tidying up as well. Will give the engine a good service, and replace a few bits.

I've previously owned a Ceasar Thundercar. I'm hoping its going to be 90% a Thundercat, but the practicality of a normal SIB. Certainly the inside deck space seems much larger.

I was put off by a normal SIB due to their sea capabilities. The Thundercats were amazing even in terrible weather, I never felt worried even in big surf or large swell.

Its got the good old Tohatsu 50hp 2S, so should go alright.

[ThundercatRob]

Originally Posted by 69cmw

Attachment 136690

I have a Surfcat [emoji41]

Looks

Who makes that? Is it a Ceasar? What's your thoughts on them?

[Roflhat]

Surfcat is pretty close to the ideal all rounder in my opinion. Almost as fun and fast as a thundercat but with 5x the versatility. When I retire from thundercats I’ll get a surfcat again.
Yeh Ceasar make the surfcat

[RickW]

Well Bob hopefully see you on the water - I do think if rib is not the answer then zapcat / surfcat / GRX is a very interesting choice

I would have gone for one but ended up with a Ribcraft 6.8m funny how things change !

[jeffstevens763@g]

Originally Posted by 69cmw

Attachment 136690

I have a Surfcat [emoji41]

https://www.youtube.com/watch?v=GSK1NPjX0BM

[RickW]

Cool vid ! Are surfcat/grx420 less slammy that the typical sib (compared to ribs)

[Roflhat]

They almost never slam, very occasionally have a hard landing when you jump a wake and land on the following peak. But in normal use they never slam, got a cushion of air between the hulls which dampens the ride

[ThundercatRob]

Thanks for all the information. Certainly looking forward to getting out in it.

Not sure if my arm will last long hanging onto a 50hp. My old Thundercat had a steering damper. This hasn’t, so it will be interesting to see how much I have to fight if it.

[Roflhat]

There's a tiller extension + damper set up for sale on ebay just now

[ThundercatRob]

Yes, I did see that. That's the exact same setup i had on my Thundercat. Have you ever driven one without a damper?

I'm keen to try it without first to see what its like. The previous owner said he kept it standard so there was more deck space inside the boat.

[ThundercatRob]

Managed to get my trailer engine support made and fitted. It’s slightly to low at the moment, so need to adjust the cross member it’s bolted to, but should work as intended.

[ThundercatRob]

Managed to do a bit of work on the engine tonight.

Started off with the impeller. I dropped the leg off and opened up the housing. Impeller was ok, but I noticed that the housing was cracked, so I’m going to need to order a new one. So I put all the old bits back in.

I’m not sure if this is common, but I had a cracked housing on my Thundercat Tohatsu 50.











I did manage to empty the gearbox oil out and it looked clean which is positive.

Any marine grease recommendations?

[ThundercatRob]

Finally got the boat out for its first outing.

Engine wasn’t 100%, so I’ve currently got the carbs off for a clean and ordered some new coil packs. I will also get a few new bits, like fuel pump kit etc. Hopefully this should sort it out.

[ThundercatRob]

Well had the boat out this week. Launched down at Loe Beach, in Cornwall.

I’ve recently replaced all the coil packs with upgraded Naraku racing ones, cleaned all the carbs and rebuilt the fuel pump. The engine is running much better now.

Thanks Roflhat for all the help and advice!

Top speed was a bit slower than I had hoped. However I’ve noticed the throttle isn’t opening fully, so I need to adjust that. I might also take off the prop guard to see how much that takes off the top speed!

[ThundercatRob]

Throttle now adjusted - hopefully correctly.

Flaps are now fully horizontal at WOT on the tiller.

Heading down to Hayling Island tomorrow to launch at the Ferry Boat.

I think I might also unbolt the prop guard as well and see what difference it makes.

Not sure where we will head yet, probably just head out of the harbour and see where takes our fancy.

[Roflhat]

Take that prop guard off, will never go back on