Category Archives: Projects

Projects are build diaries of projects. Once the projects are complete they will move into General Diaries.

Fletcher 21SS

Fletcher 170GTO Ownership Specifications and Thoughts

The Fletcher 170GTO is a very popular boat. Fletcher made it in this form for some 20+ years. And there are thousands about. But what are they like to own? I’m going to try and share my overall limited boating experience with you.


The Hull: The 170GTO is a really capable hull. Its design lends it self very well to the UK coastal waters. I can say this as I have covered some pretty serious trips in mine. The longest coastal trip was nearly 50 miles from Falmouth to Plymouth. It wasn’t in mirror calm weather either. In every case the boat has been able to withstand more abuse than me, and except in some windy conditions its a very dry ride, with it being unlikely to cover the occupants (at least in the front!) in water.


I don’t have my boat setup for outright performance. If I could compare it with a road car it would probably be something like a ‘normal’ Mitsibishi Evo(!!!) reason is, the grip is fantastic. With my setup which is a 21 Laser II prop, and an approx 200hp 2.0 Mercury V6 (again not optimised so assume around 150-160hp) the boat will clock GPS 56mph, but I can turn fast and the back of the boat does not skip, and unless really pushed with the trim to high the prop does not even cavitate. It’s a very good all round boat.


Really? Ok well since you asked. My engine is OLD its OLD tech carb 2 stroke. It doesn’t get worse¬† than this. Typically I average around 3MPG. It can be nearly 4-5MPG, and easily as bad as 1.5MPG. Best economy is around 20mph with two people where I can get just about 1 mile per litre of fuel.

Here is a set of averaged data taken over a week holiday in Falmouth 2013:

Total Fuel: 315.6 Litres
Total Distance: 251 Miles
Average MPG: 3.62
Max Speed: 55.1MPH
2 stroke oil: 7 Litres
Total Engine Run time: 14 hours.
Total average speed: 17mph.

Would I recommend one of these boats? Definitely, but check for ROT the transoms all go just like mine eventually.


Now up to date

So little has changed since 2013 on the Fletcher 170GTO. It has travelled many trips now and covered in excess of a thousand miles.

Very minor things were changed/fixed like broken seat mounts and a couple of dials but really, but boat has been very good indeed, and work has moved onto the Waverider Quantum 580, so you need to go and read about that one next!!

More stuff

The only niggle with the last engine is at full throttle it seemed to be starved of fuel (or so I thought) so I have now fitted a facet electronic fuel pump and removed the mechanical one. Its a similar set up to what mercury specify anyway. In addition the trailer has a new pair of tyres, and I also have replaced the bearings. After removing the old ones I managed to identify the ones I needed and placed an order for bearings and seals, with a couple spare just in case.


In addition these also arrived and have now also been fitted:


I’d be interested to hear from people who have fitted these for some advice on setup. I.e. how do you know if they are too hard? Too soft I get, but I just wondered what the effect of too much stern lift would be with the smart tabs.

In addition, I have a Garmin GFS10 fuel flow sensor and a stainless prop to put on. This has all been a bit of a crazy bit of upgrades due to the fact I’m taking the boat to Cornwall later this week for a bit of a holiday.

Two trips out and new engine required!

So the old engine (of unknown origin and questionable health but cheap enough to take a gamble) died or rather was rendered non sea worthy after an inspection from the last trip so something had to be done about it. That came around in the form of a SST120 (I thought it was an XR2 at first) power head. A hotted up 2.0 making about 200hp at the prop – in race trim.. After a good inspection (learning more all the time) I decided it was for me, and the purchase made.

So into the workshop for fitting:

Onto the new stainless plate for the lower cowl support.

Then was time to test the ignition. One bank was dead, (was unable to test before) so swapped around stator wires, and the problem swapped sides. Did a stator test and it was faulty. I managed however to get a working one pronto.

‘new’ style cowl fitted. Need to replace a couple of clips on it.

A few other bits I also had to do such as sort the fuel pump and re-wire it to fit my older controls. That was all done and then it was ready to test Sunday afternoon. However due to time running away a bit I ended up getting to Sheerness later than expected. and the tide was all the way out oops.

More can be read about this in the 170 GTO Trip Diary, but this engine solved all the issues of the last and is a beast!!



This bank holiday weekend had to be the final BIG push to get some serious work done on this boat. Once again I reeled in the support of my friend Si, who was equally looking forward to getting out in the boat again.

We had two days to sort out the boat hardware, and also wiring gauges, along this with the engine needed a final ‘fitting’ this time with sealant used on the bolts etc. Also bilge pump needed fitting and float switch nav lights fuel pipework/filler, backup engine mount etc..Quite a lot to do

So Saturday we finished mounting all the hardware and physically fitting everything on to the boat that it needed to run. New rear towing hooks were fitted, along with new stainless rear cleats, The outboard backup engine bracket was also mounted, with as good as guess as possible for height (turned out I need to raise it a few inches but will modify the bracket, rather than the boat.)

What else, ah the fuel tank filler also needed mounting, but the old hole in the boat was too large, so a new one was cut and and the old one was filled. That will need finishing at some point to hide the repair, then new fuel line and in line filter was fitted. The filter sits inboard in quite a nice accessible place so thats easy to check.

A temp fuel gauge was wired in now and 10 litres of fuel put into the tank. This was JUST enough to prime the system, but not enough to run, so its safe to say approx 10 litres of the tank are inaccessible, then we added another 10 litres, this now showed ‘E’ on the gauge. Its useful to know exactly how much fuel you have on the gauge, especially around empty so this was noted. Finally another 10 litres put in and now the gauge sat at about 1/8th. Now with the engine primed it could be started – and it did first time. Perfect.


Finally the hydraulic helm steering was fitted, pipes attached and the system bled.

After a few more bits and pieces that was Saturday done.

Sunday was more about the wiring and prep. At this point no wiring was on the boat. New cables had to be run from the battery to the glove box where a 6 way fuse holder was fitted. From here power was taken to the lights, radio, GPS and switched feed for bilge pump (in addition to full time auto). Surprising how much there was to do but by early eve we had fitted new tilt and trim relays, put main power feeds in, wired in the radio, nav lights (inc dial lights) power/ignition to rpm, etc etc clamped the battery down finished the bilge pump wiring and also tested everything. I also like the previous boat bonded the depth sounder to the bottom of the hull so it fires through. This will eliminate the chance of it being bashed off somehow from under the boat.

By now everything was fitted and tidy, and we ended up with something rather like this:



What amazes me is how much space we now have on this boat. Compared to the old 165 its immense. Just now need to come up of a nice way to store things!

So that brings us to the first test. But here is a sample of how it looked today. (Note I’m reposting this in 2015 and I still remember this day, it was amazing)


I’ll get some more pics as soon as I can for the rest of what I was done, but that will be posted under trips.

Trailer service and engine fitting

Now the engine is ready for some testing, I wanted to get on with the boat some more. With the floors now cut and ready, and the trailer needing some attention it was time to take the boat back to the workshop and get some more awkward stuff out of the way.

This time I was joined by two mates, who are both now getting excited at getting this on the water. So first thing was to see if we could get it onto the ramp. Amazingly we managed to do this, but had to remove the mudguards to get the swing arms under the boat:

This brings back memories!!! Only minor issue was that since there was no outboard on the boat, it was a bit front happy, so we strapped the boat down to the ramp legs just to be on the safe side.

And then on to the trailer we went. First thing was to deal with the rather tired bunks. One had snapped at some point (FYI I’ve never launched this boat yet, and the trailer has never been looked at before by me) and all of the bunk hardware was looking pretty bad.

Snapped bunk. Very rusty indeed.

This fitting was still intact, the one opposite had fallen apart. However all of it had to go, so it was all stripped off and thrown away.

The next bit to remove was the old winch. It again was looking very tired and rusty (in the background of this pic) It was replaced with one I’d got from the SBR boat show a couple of years ago. Oh and also the hitch was very stiff. It took two blowtorches and a fair bit of force to remove an old stuck nut on that, and then it could be serviced and cleaned. The other thing was that the box section 4×3 inch is obviously hollow. Due to the forces on the jockey wheel it had partially collapsed. So I cut a smaller piece of box section up and hammered it in the front open end of the trailer metal work. This pushed out the dent and now gave the bolts that pass through that box section and hold on the jockey wheel something to clam down on. Another annoying job fixed!!

In the end the front of the trailer now looked like this:

Next was the floor, that had to be ground clean and wiped with Acetone then I glassed down the cut pieces of wood.

So I took a rest on Sunday, and made a plan for today. A little trip to Southampton this morning to a company called Extreme Marine and I came back with the following:
Can’t recommend Extreme Marine high enough. I called them in the morning said what I wanted to do and was told no problem just pop down. They had every single thing you could ever want for a boat trailer and made them in house. I’ll be going back there for sure.

So this bit was quite good fun. Like a large Lego kit I assembled the parts and put them on the trailer. After a few test fittings (gotta love the ramp) I had it done.

Amazing transformation!!! Can’t wait to try this out…

So the boat was lowered back onto the trailer and everything checked. No problems here so now it was onto mounting the engine.

Test fitting the engine, to work out holes..

This was horrible drilling new holes in a new transom – but all for a good cause. If interested like my old blue boat, I offset the engine again to help counter prop torque. It seemed to work really well on that blue one. Not so much on this one, just one inch.

Engine on!!!! This is a test fit really, as it will have to be removed. There are a few issues I need to address with the steering system. Not sure what my options are at the moment. Looking good though ;)

Tilt and trim works!

So that’s it for now. But getting there. I can smell sea already!

Internal stuff

Managed to get some time on the hull again on Saturday, and was joined again by my mate Simon who gave a hand. First up was to pull up the final small pieces of rotten floor. This was only a small area, and in fact wasn’t so rotten really. It had de-laminated, but it appeared due to stress cracks rather than being rotten. Either way it was cut out an a new piece laid in its place. The final piece to do was the piece of floor that was cut out that covered up the rear of the boat into the bilge area. I decided to lay the pump and float switch in this area as to cut out as small an area as possible from the floor. Things tend to fall down into the space otherwise.

Both bits of new floor can be seen here:



All being well I’ll get this glassed in this week. Then it all needs painting and its ready to be kitted out. Need to decide now where I can put the battery and other parts.

We did remove the fuel tank. I wanted to physically measure it, and came up with a value of 80 litres. I’d like more but realistically I’m only going to get in another 20 litres or so if I replaced it, so I think that can stay. for the time being.

Here is Si, trying to measure the tank before we just decided to pull it out and check it over :)

not the most spacious of cuddies ;)

More engine stuff

Ok so a little more on this engine:


As I said last time I took out the carbs for a rebuild. After I had freed a stuck throttle shaft, they were ready to go, after nothing more than a basic clean.

I decided today to tackle the ignition system. These don’t like corrosion, and rarely get maintained.

So first job was to pull a pair of coils off and give them a clean. Again this is not a big budget build, its just a good service tidy up and reassemble, using where possible serviceable parts.

Cleaned coil on the right.

Then I gave the plate a good scrub with a wire brush.
You can see here there is a region that was not painted. This is for a wire to rest against. I’m not quite sure what its purpose is, that I must find out. But it causes corrosion like on my other V6 220HP engine.

Top one done, middle and bottom to follow. I wasn’t intending on doing them all today, which is why its not been done in one large section. Looking much better however!

After this I decided to see what I could do with the wiring loom. I hate mercurys looms which are covered with tape. They look so messy around the back. I decided to see if I could cover them with some plastic wire sleeve which I use on car looms.

Its a bit hard to see if you don’t know what your looking for. Spot the two small wire harnesses. One covered in tape the other in a nice clean plastic sleeve. It worked a treat. I’ll do the other one next week.

As it stands now. Will finish this off next week. Hope to paint the bilge area of the boat over the weekend. Then its ready to mount the engine.