DRAGONFLY Trimarans User Forum

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DF920  Hull

These are archived postings from the first Dragonfly User Forum from 2001-2006. Lots of useful information to be found here!

Here you will find all the information about the Dragonfly 920’s Hull.

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Antifouling | Cleaning

Re: Sticking centreboard after beaching
[from: Ipe Piccardt Brouwer, Netherlands, 27 Oct 2006]
I had a similar problem recently, after having run up the beach a little earlier than expected. The centreboard downhaul released automatically, but then the board jammed halfway up, leaving us stuck in the mud. After freeing the boat from the mud I managed to winch the board down.
I am under the impression that the jamming was caused by slack in the centreboard uphaul line. I have now rigged a piece of shockcord to take the slack out of the line, next time the centreboard is raised involuntarily.

Re: Sticking centreboard after beaching
[from: Malcolm Ratcliffe, UK, 27 Oct 2006]
In May 2003, Bill Fraser posted a message about his 920’s centreboard sticking in the trunk after beaching, and asked if anyone knew what the problem was likely to be. My DF920 did the same this year, after I dried her out on a beach gently. I managed to winch it down eventually, but only by winching very, very hard. Anyone any ideas where the sticking is likely to be? Definitely nothing stuck up the slot;- all clean. What did Bill Fraser find the problem to be?

I used to be an F boat owner, and now & again, Ian Farrier would contribute to the website forum to help out with any recurring problems. Would be nice if someone from Quornings could spare a few minutes now and again to do the same for us Dragonfly owners. Obviously can’t be done for every little problem;- they have a business to run and are busy people. But a bit of help with recurring problems that come up on this site would be very much appreciated, and no doubt lead to an increase in ‘brand loyalty’, and continued sales? What do other DF owners think? What do Quornings think? I can’t believe that they don’t monitor this site?

Re: DF920 Leaking like a sieve – FIXES
[from: Malcolm Ratcliffe, United Kingdom, 17 Aug 2005]
About a year ago I reported that my DF920 was ‘leaking like a sieve’, and since then I have been tackling the leaks one at a time. The boat is now dry. Leaks and their cure were as follows;-

Wet lockers behind seats in saloon. Caused by window sealant having dried out between the frame and GRP deck moulding. Windows removed, old sealant removed, new sealant applied, and windows re-fitted.

Water in rear under floor locker. One leak from Wallis diesel cooker exhaust through-hull fitting. Found no sealant at all under flange of fitting on exterior. Marine silicon sealant applied, and fitting refitted.

Second more serious leak from the two through hull bolts securing rudder bottom bracket straps. When boat out of water, bracket removed, old sealant removed, and bracket dry fitted to hull recess. When bolted up, rudder would jam when more than about ten degrees out of fore and aft. Found that bottom bracket aft end was bent to the wrong angle, which meant that every time the rudder was put over past about ten degrees, the whole assembly was trying to lever the bracket downwards, therefore ‘working’ the through hull bolts, and causing the leak. Impossible to bend the bracket any more, so stainless washers used on the rearmost of the two bolts to pack down the aft end of the bracket until rudder fitting movement was unimpaired. Resulting slight gap between bracket strap and hull recess filled with epoxy thickened with microfibres;- bracket strap bedded in to this ‘bog’ of epoxy.

Leak from main saloon/heads bulkhead, which exited at joint between table top/centreboard casing/bulkhead. This water was leaking from the trunk tht carries the centreboard lines from the mast step down to the board. Water is meant to drain down the trunk, but should not ha ve been exiting into the saloon. Quornings suggested removing the mast, and checking that there were two short lengths of pipe from the mast step area down into the trunk for the first approx 100mm;- apparently some earlier models did not have these pipes, and this sometimes caused rainwater to blow sideways under the deck. I had mast craned off, and found that the pipes were there. I therefore took off the table and its aluminium base plate, so that I could try & feel up into the trunk at the forward end. (Awful to get off, as screws corrode into the ali plate, and can’t get screwdriver squarely onto screwheads. Have replaced with hexagonal head screws to make job easier if ever has to come off again). Very little room to get fingers up into trunking, but found that too much sealant had been applied around sides of trunking/centreboard joint, and resulting large beads of sealant directed water aft to where the table had insufficient sealant at its forward end, and allowed the water to leak out. Old sealant excesses were removed, and whole area re-sealed using Sikaflex, as per Quorning’s suggestion. Leak is cured, but I am not impressed that bare timber can be felt up inside a trunking that is designed to carry draining rainwater. If the leak were to appear again, I would insert plastic pipes over the centreboard lines, down from under the maststep right down to the centreboard sheaves at the bottom of the trunking, and then fix them in place by using squirty expanding foam.

Occasional damp patch in main saloon/heads bulkhead at floor level, to port of the centreboard casing. Leak from one of the six fixing screws in the top plate of the jabsco toilet, and also leak from under whale pump action tap on sink in heads. The tolet leak in particular caused the wetness to sometimes seep through to the saloon side of the bulkhead.

Hope my findings might help others. Regards Mal
[Looking at all the previous correspondence to this theme this seems to indicate a number of common problems with the DF920. I would recommend to all DF920 owners to check on their boat these points and have them fixed before the boat suffers long term damage.

On this note I would also recommend to take off the genoa tracks and make sure the fixing screws were well bedded in sealant and no destructive moisture has crept into the foam sandwich. Bo]

Re: Leaking like a sieve/leak in the floats
[from: Jacob Blom, Netherlands, 30 Jan 2005]
We own a DF800SW and also had a problem with water leaking in the sidehull bilges. We found out that the problem was the Sikaflex round the backstayshroudplates. After some time the connection between the shroudplate and the rubbercompound is lost because the shroudplates move al little bit towards the centre of the boat when the shrouds are tensioned. We solved the problem by applying new Sikaflex every 1 or 1½ year. Perhaps the 920 has the simular problem?

Re: NUTS / BOLTS torsion / tension
[from: Larry, United States, 30 Jan 2005]
You should have two nuts on each attachment. The bottom one should be adjusted tight enough so there is no “play” and loose enough so you can open and close the folding mechanism without too much resistance. The top one should be tightened hard against the bottom one to lock it (using a second wrench to keep the bottom one from turning).

Re: NUTS / BOLTS torsion / tension
[from: John Blaiklock, United Kingdom, 30 Jan 2005]
I don’t know the torque for the various bolts on the 920. Quorning don’t specify them in their manual, even though they should.

I use thread lock compound (TLC) to stop my nuts and bolts coming undone on my boat. A medium strength TLC is suitable, for example Loctite 243.

Halfords is a retail supplier of TLC in the UK, and if they sell just one type, it is usally Loctite 243.

There is lots of infomation at www.loctite.com.

Re: DF920 Leaking like a sieve/leak in the floats
[from: Nikolaus Rollwage, Germany, 21 Jan 2005]
The swimmers are not completely sealed off. There are small holes in the center of both bolts that connects the swimmer with the beams (I refer to my DF800, but have seen the same on a DF920). That makes a pressure balance possible.

The beams protect the holes from front and top, but not from behind. For example, if you rinse the swimmer-beam-connection with a hose from behind to remove salt after a long trip, some water will drip into the swimmer. Therefore, a bit of water is not necessarily a sign of a problem. One may put some tape on top of the bolts before rinsing/before a stormy trip to test it.

NUTS / BOLTS torsion / tension
[from: Julian Dimock, United Kingdom, 21 Jan 2005]
Over the years, some of our 920 nuts have become loose; and on two occasions they even fell conveniently into our trampoline!! Has anyone any suggestions, please, with regard to the settings to use with a torsion spanner?

The nuts & bolts referred to above are those associated with the structures that support the AMAs.

Re: (Sliding) Hatch parts required
[from: Larry, United States, 19 Jan 2005]
I also needed those parts, and found the rubber bumpers at a local hardware store. I’m using similar bumpers on the transom as rudder stops. These are a common item — you may not find the exact size but in this case any close size will do the job.

The pile weatherstrip is commonly used for aluminum storm doors and window tracks in the US. It’s often referred to as “wool pile weatherstrip” even if it’s not wool. I found a few sources for it using a Google search for the term [Pile “weatherstrip” gray].

Also — Quorning uses a gray rubber sealant (that doesn’t harden) to seal the holding tank and some other places. I found out it is made of butyl rubber and have tried some substitutes that may work well based on some testing in my cellar. I’d appreciate info if anyone knows a retail or online source of the exact material Quorning uses.

(Sliding) Hatch parts required
[from: John Blaiklock, United Kingdom, 19 Jan 2005]
The main hatch (sliding hatch over companionway) on my 920 runs on strips of grey fabric with a fluffy texture. This is wearing and I want to replace it. Does anyone know a supplier?

Also the rubber bumpers that the hatch hits when it has reached the end of its travel need replacing. Again, anyone know where to get these from?

Re: DF920 Leaking like a sieve
[from: Ernst Fellner, Germany, 9 Jul 2004]
Another leak in my DF 920/57. (Bitte um Übersetzung, Bo kann das besser):

Ein weiteres Leck lag bei meinem DF920 im Ankerkastenboden. Die Stuzten für Wasser und Fäkalien-Absaugung waren mit zuwenig Dichtmasse montiert, teilweise auch nicht exakt festgeschraubt. Dadurch kam Wasser in den Bug-Kollisionsraum. Bei mir mal bis zu 15cm hoch. Neumontage mit Dichtmasse hat das Problem weitgehend behoben. Gelegentliche Inspektion durch das Luk unter dem Kojen-Polster ist anzuraten.

Eine weitere Undichtigkeit besteht bei mir in den Schwimmern. Nach einem längerem Tör steht immer gering Wasser in den Schwimmerbilgen bds.( Inspektionsluk am Boden der Schwimmer-Backskisten ).
[Another leak was in the bottom of the bow anchor locker. The connector for the fresh water and the dirt water connectors were installed with not enough sealant, and partly not screwed down enough. Because of this water entered in the collions compartment. I had once 15cm of water in it. Refitting the connectors with enough sealant has solved the promlem. It worthwhile to do an inspection from time to time through the inspection cover, which is located forward under the front berth.

Another leak is in the floats. After a longer trip there is always a little water in the bilges of the floats (inspection cover in bottom of centre locker). Bo: This is apparently normal and depends on how ‘wet’ you sail. Pump it out from time to time.]

Re: DF920 Leaking like a sieve
[from: Bo Wetzel, 7 Jul 2004]
Leak no. 4, which I also had was cured at the next time when the boat was out of the water for antifouling. One needs to remove the bolts, clean everything off and remount the bolts with lots of sikaflex.

Another leak in my aft cockpit locker was from the trough-hull fitting of the cooker exhaust. The yard hat fitted it without any sealant. This was solved by removing it, cleaning it and applying sealant (sikaflex) and refitting it.

The previous owner of my boat also has had leak no 3 which, I believe, was a problem with the down/up-haul rope/roller mechanism for the centre-board which is close to the mast step. This, I believe, was solved by an intervention of Quorning Boats.

Leaks from the sliding hatch seem a common problem on the DFs (see other contribution on this forum), this accounts for water on the saloon floor just before the under-cockpit drawer. This is hardly a problem if you have a sprayhood, otherwise some mods need to be made to the sliding hatch.

Re: DF920 Leaking like a sieve
[from: Malcolm Ratcliffe, United Kingdom, 7 Jul 2004]
Thanks to John Blaiklock for some suggestions.

Since writing my first mail, I have had opportunity to do a little more investigation. The leaks in the lockers behind and above the saloon seats do seem to be coming from the windows. Foam behind the vinyl is soaking wet. Rubber seal between window and frame looks OK, but between frame and GRP looks suspect with dried out mastic.

Leak below mast down inside main bulkhead, and then out by the table, is definitely not coming from the three wiring sockets behind the mast. Has anybody experienced leaks from mast step?

In the rear cockpit floor locker, I can now see water coming in around two rusty nuts which are glassed into the bottom of the hull. These are presumably the nuts/bolts holding on the bottom rudder strap, so presumably boat out of the water job?

Anyone any comments yet on the worn bottom rudder bearing, please?

Most of the cabin lights in my boat work without any switches being on at the main switchboard. So the supply must be by-passing the main board? Is that normal, because that surely means they are unprotected by fuses?

Re: DF920 Leaking like a sieve
[from: John Blaiklock, UK, 5 Jul 2004]
I have had leak number 4 in mine. The rudder post goes down through the aft cockpit locker, in what I imagine is a metal tube, which is covered in gelcoat or resin. This gelcoat/resin had a slight hole in it on my boat, which looked like it had been there since built. There were water stain marks coming down from the hole, showing that water had entered here. The shape of the hole looked like it was a slight build fault rather than intentional or a subsequent failure. Check all your fittings in the cockpit locker while you are down there for water stains. There are others that could also be leaking, like the bilge pump hose skin fittings.

I filled in the hole with GRP repair filler, no more leak, and a dry locker. It was difficult getting my body into the correct position to apply the filler though. You need to be right in the locker head first to see it.

Leaks 1 and 2 sound like typical window leaks. All boats seem to suffer from this eventually, but must be fixed to preserve the woodwork. Window leaks often go behind lining, which sounds like what yours is doing.

Leak 3 sounds serious with potential for expensive damage. Can you keep the boat covered under a tarpaulin until it is fixed?

Leak 5 could be a failure of the sealant of the screws that hold the cockpit locker hinges and catches to the cockpit floor. These are self-tappers that go straight into an area of foam cored GRP, not a great design. The water could then come out of the screws on the underside of the cockpit floor, for example those that attach the washboard holder. Remove all these screwed fittings from the cockpit floor, clean, and replace using Sikaflex sealant.

Another common leak that is easy to prevent with some simple maintenance is through the 3 large hatch’s 6 handles. These handles require annual disassembly and regreasing to keep them working properly. Remove the single crosshead screw on the inside of the handle, pull apart from both sides, and regrease all moving parts with Vaseline, particularly the O-ring that bears agains the hatch transparent material. If the O-ring is perished, cracked or missing, replace it. It is a standard metric size, it does not have to be from Moonlight.

Anyway, that makes 3 920s in Wales: yours, one in Beaumaris, and mine in Pwllheli. Because of our wet climate, I expect we will soon become the Dragonfly leak experts.

Leaking like a sieve
[from: Malcolm Ratcliffe, United Kingdom, 2 Jul 2004]
I am now the proud owner of DF920 No 34, and am keeping her in Swansea Wales. Have only just brought her in to Swansea last weekend, but boat leaks like a sieve, and I wonder if any owners have had similar leaks, and might suggest their source?

Leaks 1 & 2 are filling the lockers under the windows in the saloon. At the aft end of the locker on the starboard side, there is a small hole up in the top corner under the shelf, below the vinyl covered strip screwed to the hull side. I cannot see water coming down from the windows on the face of the vinyl, but I suppose it might come down the back of the vinyl and into the locker. In heavy rain the locker fills to the front lip of the sliding doors in less than 24 hours. Similar leak port side, water runs back via grooves in hull moulding into wet locker on port side of saloon companionway.

Leak 3 is coming down inside the main bulkhead between the saloon and heads, and exits in the saloon where the table is jointed into the bulkhead, producing a wet stain in teak of bulkhead. Water comes out there and runs down centreboard case on starboard side.

Leak 4 is coming from rudder mounting area in cockpit locker. Broker suggests three through-hull nuts and bolts holding lower rudder bracket might be the source, but I haven’t had chance to look yet.

Leak 5: Also big puddle of water, where you step down into saloon. I thought it might be coming through to there from the leak in the aft locker, but broker doesn’t think so. It is definitely not coming down throught the main hatch and washboard, and looks as though it might be coming forward from under the big under cockpit draw.

Have noticed that bottom rudder bearing appears to be worn. Have not had chance to dry boat out for a good look yet, but appears that the hole in the horizontal plate is a lot bigger than the pin sticking up. What has worn, the pin or plate? Has anyone else had to fix the same problem? New parts, or can it be bushed?

Any advice would be most welcome. Smashing boat by the way, doesn’t half go!
Thanks, Mal

Decorative grey tape for DF920 beams
[from: John Blaiklock, United Kingdom, 2 Jul 2004]
The decorative grey tape on my forward beams is becoming chipped and scratched and needs replacing. I have found a supplier who sells an exact match of what is there already.

SAC Graphics, Enville Street, Stourbridge, W. Mids. DY8 3TD. Tel: +44 1384 443744


Colour is Smoke, width is 1.5 inches.

Center-Board Problems
[from: Bill Fraser, United Kingdom, 31 May 2003]
Yesterday I dried out on a clean, sandy, sheltered beach just inside Bembridge harbour on the Isle of Wight (very much recommended if you have the chance). On lifting off, I couldn’t get the centre board down. Fortunately I had a strong block and tackle on board (useful for MOB recovery hung from the backstay) and, at the risk of breaking everything, managed to get the board down by hauling t he downhaul line sideways with the block and tackle attached to the mooring cleat I have mounted on the outside of the forward port beam.

I am going to have to lift the boat out next week to have through-hull transducers fitted (see my earlier post) and wonder if anyone can give me some tips on freeing up the centre board while the boat is out of the water?

Supporting the hull correctly
[from: Larry Furst, USA, 4 Dec 2002]
Placement of the 920 on the storage cradle is extremely important.
If using a lift or rail-launching system to place the boat in storage, incorrect placement can cause point-stresses that can deform the hull as it settles. The hull is foam core, and the cradle is designed to rest on reinforced structural hull sections that are solid (not cored). The forward support must be directly under the forward beam, and beneath or just ahead of the front waterstay attachment point…almost touching it. The aft end of the centerboard should be just slightly ahead of the cradle’s aft support pad, so that the centerboard can be lowered while the boat is on the cradle (I leave it raised). It is also important to make sure all cables are clear before the boat comes to rest on the cradle (a cable caught between the hull and the cradle can also cause damage).
New owners should take note of the way the boat is positioned on the cradle or trailer as it comes from the Quorning factory.

Spinouts on rudder in rougher conditions
[from: Stefan Poelkow, Germany, 29 Oct 2002]
Has anyone experience with spinouts in rougher conditions? Has anyone experience with solutions like fences on the ruderplate? I have mainly had spinouts (stroemungsabrisse am Ruder) wile sailing with the Gennaker.
[BO: See Larry Furst’s reply in the Sail-Trim section of DF920 RIG/Sail]
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Re: Whats the hull area of the DF920 for antifouling ?
[from: John Blaiklock, United Kingdom, 2 Dec 2004]
I don’t know the hull area for antifouling, but one 2.5 litre tin of antifoul is sufficient for mine. It will do everywhere once and leave some left over for a second coat in areas of high wear or fouling, i.e. the foils and just below the waterline.

I used International Cruiser Uno this year. I sail all year and it is just starting to wear out after 9 months of sailing. The paint wearing thin during the winter is not a problem in the UK as there is very little marine growth now anyway.

Whats the hull area of the DF920 for antifouling ?
[from: Mark Wilton, United Kingdom, 30 Nov 2004]
Can anybody tell me what the overall area of the hull(s) is when it comes to anti-fouling? Many thanks.

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