GRP Enterprise Dinghy Floor and Tanks
Printed From: Yachts and Yachting Online
Category: General
Forum Name: Repair & maintenance
Forum Discription: Questions & tips on the subject
URL: http://www.yachtsandyachting.com/forum/forum_posts.asp?TID=12402
Printed Date: 25 Jun 25 at 9:01pm
Software Version: Web Wiz Forums 9.665y - http://www.webwizforums.com
Topic: GRP Enterprise Dinghy Floor and Tanks
Posted By: Smorgie
Subject: GRP Enterprise Dinghy Floor and Tanks
Date Posted: 23 May 16 at 9:51pm
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I'm new to sailing and I've just purchase an old GRP dinghy (sails have 1972 on them and number is 165**.) I have some questions and was wondering if anyone could help me out? I've only sailed it once but during the gusty conditions I managed 3 near capsizes and in doing so put about 10cm of water into the boat. On getting out I found lots of water in the two side buoyancy tanks when I took the drain plugs out. So I need to find out how the water has got there. I can't find any info on the hull design and sections. I'm guessing they should be isolated from each other and do not join to the under floor area? The edges of the floor seemed to be sealed to the tanks with silicone sealant (it's translucent and very flexible with bits missing), is this correct or should this be glassed in (and is they a void underneath the floor)? I'm just wondering if it has leaked through the floor into the sides as the level of water seemed to be similar. Both tanks have inspection holes so the water could have got in through these (they have no O rings which I'm guessing it should.) Any help would be very useful.
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Replies:
Posted By: 423zero
Date Posted: 23 May 16 at 10:00pm
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I have a Enterprise in the 16 thousands, so it is a 70's ish boat, they are very tippy boats anyway, the water is not causing this, though it could make it worse. The Enterprises from this era tend to be a bit leaky anyway, unfortunately the water can find many ways in, fix the obvious ones first (missing "O" rings etc).
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Posted By: JimC
Date Posted: 23 May 16 at 10:37pm
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Glass enterprises of that era tend to make sieves look watertight.
The floor tank join is a notorious failure point, doubtless the silicon is a previous attempted cure. I fear I haven't come across a cost effective permanent fix.if you really clean up the join area and put on two layers of glass tape, one wide, one narrow, right across the seam with luck it will make it a lot better for a while. |
Posted By: Smorgie
Date Posted: 23 May 16 at 11:15pm
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Thanks for the replies. I'm sure I can reseal the floor if I do a big cleaning job on the old sealant and reseal it with a flexible sealant. I guess that it is not a good idea to glass in the edges of the floor and gelcoat over so there is no way for water to get in? If getting water in the tanks is common is there anything in there that the water will damage in the long term, for example wooden stringers?
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Posted By: transient
Date Posted: 24 May 16 at 12:59am
| Another weak spot on some old fibreglass ents is the join between the front storage compartment walls and the underside of the foredeck. This doesn't become evident until you have a complete capsize, at which point it becomes a disaster. The solution is the same as Jim mentioned for the side tanks. Bit more fiddly though due to tricky access |
Posted By: Rupert
Date Posted: 24 May 16 at 6:30am
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Nothing really sticks well to gelcoat, so any fix breaks in the end unless you grind the gelcoat off the area you are fixing (so the bottom of the tank moulding) and then glass onto that as jimc describes. A very messy job, but not hard.
An easy but temporary solution is duck tape. Works surprisingly well for a few weeks. Get proper stuff, though! ------------- Firefly 2324, Puffin 229, Minisail 3446 Mirror 70686 |
Posted By: JimC
Date Posted: 24 May 16 at 10:47am
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A flexible sealant won't work I'm afraid. The problem with side tank joins is that we walk and jump around on the floor, which bends and distorts under foot, especially on a glass boat where the floor isn't that rigid. But because the tank side is pretty rigid (being vertically aligned) the joint is continually opening up.
To be brutally honest I'd counsel not to worry about long term life. The 70s glass Enterprises really aren't built well enough to worry. Get some life out of it for your money, and when it gets too much hassle skip it. Rupert may well have a very good suggestion with duct tape, at least assuming you are sailing inland with safety cover. Slow the water ingress so the sailing experience is reasonable and you'll be OK. On the other hand if you are sailing on the sea, or without decent safety cover, well, all I can say is that I would not use an old glass Enterprise in those circumstances. |
Posted By: davidyacht
Date Posted: 24 May 16 at 11:16am
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You could put some 4" hatches in and feed in some long bouyancy bags which would help the boat float and displace any water in the tanks ... I dont know about the class rules, but I guess that you don't need to seal the tanks if you could get buoyancy bags that fill the space. ------------- Happily living in the past |
Posted By: Rupert
Date Posted: 24 May 16 at 11:47am
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Or lots or plastic 2l lemonade or cider bottles, just to endure you don't sink! ------------- Firefly 2324, Puffin 229, Minisail 3446 Mirror 70686 |
Posted By: transient
Date Posted: 24 May 16 at 1:27pm
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The one I had experience with (No. 12506) had polystyrene already installed. Discovered it when I cut 2 inspection hatches into the tanks. To answer the earlier question, there are wooden fillets in the tanks that the thwarts screw into. |
Posted By: SUGmeister
Date Posted: 24 May 16 at 3:00pm
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Could try putting in swimming pool balls, 4" diameter http://www.amazon.co.uk/dp/B00O59AJZI/ref=pd_lpo_sbs_dp_ss_3?pf_rd_p=569136327&pf_rd_s=lpo-top-stripe&pf_rd_t=201&pf_rd_i=B00OEDG8CI&pf_rd_m=A3P5ROKL5A1OLE&pf_rd_r=GPTFXRMEKKTQZA64QC6W" rel="nofollow - https://www.amazon.co.uk/dp/B00O59AJZI/ref=pd_lpo_sbs_dp_ss_3?pf_rd_p=569136327&pf_rd_s=lpo-top-stripe&pf_rd_t=201&pf_rd_i=B00OEDG8CI&pf_rd_m=A3P5ROKL5A1OLE&pf_rd_r=GPTFXRMEKKTQZA64QC6W ------------- Simon SUGmeister I wondered why the baseball kept getting bigger. Then it hit me. |
Posted By: JimC
Date Posted: 24 May 16 at 5:00pm
| Dunno about you Simon, but I think the noise of a few hundred plastic balls rattling around the tanks would drive me crazy, but the cost of buying so many that they could be crammed in too tight to rattle would be prohibitive. |
Posted By: jaydub
Date Posted: 24 May 16 at 5:32pm
With you on that one, Jim.  
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Posted By: SUGmeister
Date Posted: 24 May 16 at 5:34pm
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Think you're probably right Jim, so here's another left field idea. Presuming that you can buy lorry tyre inner tubes nowadays, put one into each side tank and soft inflate.
------------- Simon SUGmeister I wondered why the baseball kept getting bigger. Then it hit me. |
Posted By: 423zero
Date Posted: 24 May 16 at 5:46pm
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I would go for fibre glassing joint, Drill a series of 4mm/ish diameter holes in side tanks and floor, use a depth stop on floor, the resin will then go through holes and give a good physical hold, scour existing gel coat also, will look similar to taping on Mirror.
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Posted By: piglet
Date Posted: 24 May 16 at 7:13pm
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Wine bladders are light and surprisingly durable.
And more fun to drink than all that lemonade. |
Posted By: Rupert
Date Posted: 24 May 16 at 7:52pm
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Add in the cost of going to to get them and you could buy another boat! ------------- Firefly 2324, Puffin 229, Minisail 3446 Mirror 70686 |
Posted By: 423zero
Date Posted: 24 May 16 at 8:12pm
| Small Coke bottles would be easier to insert, blob them with Sika-flex they will bind together where they land, no rattles. |
Posted By: Smorgie
Date Posted: 24 May 16 at 10:03pm
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Again, thanks for the replies. I will be sailing on an inland lake with safety boat cover so I don't think I'll start drinking the wine just yet. Thanks for the tip about the front storage. I will fill it up with a hose and see if it stays full.....or disappears. So does anyone know if they originally sealed the floor and the sealant has failed over time?
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Posted By: Rupert
Date Posted: 24 May 16 at 10:17pm
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The side tanks would have been bonded to the hull with polyester resin, but the flexing has caused the joint to fail, as the resin, while the same stuff as the plastic the hull is made from isn't the best glue in the world. However, no other glue, such as epoxy, would have worked while the GRP in the layup was still curing. The boats were built with a finite lifespan, and that they have lasted this long is amazing. In order to get them as light as the wooden boats with early GRP technology, they had to build them thin. ------------- Firefly 2324, Puffin 229, Minisail 3446 Mirror 70686 |
Posted By: Smorgie
Date Posted: 24 May 16 at 10:35pm
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Thanks Rupert that makes sense now. So the water leaks in through the floor because that isn't bonded to the tank any more and because the tanks aren't bonded to the hull any more the water gets into the gets up into the tank.
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Posted By: Rupert
Date Posted: 25 May 16 at 9:34pm
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Not sure I quite got my head round that. Any water that gets into the boat will leak into the tanks where they have split from the tanks. Unless the tanks are also leaking through old screw holes or cracks elsewhere too, when water may well leak out of the tanks into the boat! ------------- Firefly 2324, Puffin 229, Minisail 3446 Mirror 70686 |
Posted By: patj
Date Posted: 26 May 16 at 6:54pm
| Unless you are actually sure that the floor-tank join is the problem, start by checking with pressure, using a pump through the bung hole and some soapy water around the possible problem points - hatches, bungs and any fittings screwed to the tanks as well as the joints. We did this on an old Wayfarer and were amazed at how much the supposedly filled holes from old fittings leaked. |