Additional Buoyancy / Flying Fifteen

[Alan_B]

Hi all,

I have been a lurker for a while, but only joined today and this is my first post so please be kind

I have a Classic Flying Fifteen which I am keen to add some buoyancy to. Unlike some of the newer 15s we just have open space / storage under the side decks. The way I see it there is two options –

A) Buy bouyancy bags similar to those used in Enterprises and other dinghies, however there is a lot of space there so could get expensive quickly.

B) I can get (for free) some closed pore polystyrene foam in blocks which could be cut down into shape and then sheeted in with marine ply. This would be more effort but in my eyes probably a better end result.

Currently there are bags at the bow and stern in the tanks.

A bit of a random question but is there such a thing as too much buoyancy? Are there any pros / cons / options I am not thinking about?

To explain my boating history & knowledge I was brought up around boats, my dad always had a double skinned foam filled powerboat at some point, various fletchers or dorys plus I was in the Sea Cadet Corps so have RYA qualifications in boat handling, general seamanship etc. The one thing I have never needed to think about before was buoyancy (apart from personal obviously).Only got into sailing last year, and this is the first season sailing on my own boat. My best mate usually takes the helm as he has more experience, having sailing on Lough Neagh for a few years.

This has come about after filling the boat in a bit of a blow on Saturday, ending up with 3 coast guard ribs to get us sorted out. I think in essense we left it too late to get the self bailers open, and she just started digging through the waves and completely flooded us. Add to that a fair breeze and gusts she was over on her side a few times too. We are also a light crew with about ~ 19 stone between us, so keeping her fairly flat can be abit of a challenge.

With the current set up she sits (when full of water) with the bow deck slightly under water, and the stern slightly above. The newer 15s have side tanks which holds them abit higher if the cockpit does flood.

Any advice / tips would be much appreciated.

 

[alahol2]

Welcome.
Bump for a new user.

 

[Stork_III]

With a dinghy too much bouyancy can be a problem, as the boat sits too high when capsized and will tend to turn turtle. With a FF you can't have too much, minimise the volume of water taken on board. Your second option sounds best if you can't stretch to side bags, but increase the bow bouyancy as well. It would be worth looking at the FF measurement rules (at BIFFA) as what you may do may not conform and will devalue the boat, classic FF are sort after in the FF world.

 

[Lakesailor]

Do the class rules have anything to say about added buoyancy ? I don't know if you race, but selling on may be awkward if you make woodwork alterations. I've sold Saftibags for not much money on ebay.

Is heeling a big issue as they are keelboats.

 

[rob2]

As others have suggested, buoyancy on a fin keel boat is never too much! I'm only concerned that if you fit closed cell foam behind panels, you will eventually find that it becomes waterlogged and disintegrates - probably best if you can work it such that it is removable. However, the closure of the volume below the foredeck will in itself reduce the volume of water that you can ship and prevent the bows from sinking - in the short term a sealed tank of air does the trick and a drain bung lets out any leaks after sailing. The same with side tanks, although you may find it more convenient to strap in some air bags here - they're much more comfortable when you fall against them!

Rob.

 

[Seajet]

An important consideration with any buoyancy is to make it really secure via webbing straps and bolts or similar, the forces exerted as bags / tanks make a bid for freedom are quite something !

Personally I'd go for buoyancy bags as they're easier to inspect, don't permanently take up design space and won't get saturated, but they are relatively expensive with a finite life.

 

[Alan_B]

Thanks for the replies so far.

Heeling can be a problem for us, as I said we are a very light crew and even hiking right out she can heel considerably. If we had an extra few stone each it would probably help a fair bit. Time to eat more KFC

If I was going to go with option two I would definatly make the woodwork all easily removable, inspect frequently and ensure it remians dry. As for value I am not too fussed, shes a 67 (I think) boat and it cost very humble money. She will be getting freshened up this winter for sure, antifoul removed and decks painted as she is going abit porous.

I guess it depends what is available to me at when I go to do it. I am nto afraid of the woodwork etc and my dad is a dab hand when it comes to stuff like this, the bags strapped in would be handier but not that elegant looking IMO.

On looking at the boat last night I can fit another bag forward of the mast but not in the watertight compartment so that should help lift the bow.

After I have made the alterations I think I will fill her up alongside the jetty to see how its improved, rather than waiting for another swimming session!

Cheers

Alan

 

[TradewindSailor]

I would go for buoyancy bags. Adding plywood adds weight and your FF is probably already overweight. Keep it light and keep it simple.

Does your bow tank come up to the deck, or do you have shelf there for the spinnaker? You could consider just leaving a small space for the spinnaker and putting another bag up there.

 

[uxb]

When I bought my old GRP 15 both buoyancy tanks were leaky and had been filled with dozens of empty plastic pop bottles- a nice, simple and cheap way to keep her afloat. Maybe a bit of netting fixed under fore and aft decks could archive the same?

 

[trapezeartist]

A bit of a random question but is there such a thing as too much buoyancy?

Generally speaking, no. But this is a Flying Fifteen we're talking about. I recommend lead.

Sorry. She may be the love of your life, but I am not a Fred fan.

 

[boaterbaz]

+1 for the empty 3 litre bottles. I stuffed the bow and stern tanks full on my old 15. Tipped her over a couple of times but never enough to be totally flooded as I was always concerned that the deck could pop off if we had a big wipe out. Lovely boats regret selling mine.

 

[William_H]

If your low body mass and heeling is a problem I would recommend fitting reefing points (or at least one) to the mainsail. This can make a wild and wooly ride in strong winds into quite a pleasant experience. You can just rely on lanyards to lash down and out the reefing points but reefing lines all easily done from the cockpit is best. You might also consider a smaller jib for thoise strong wind days.
Re buoyancy IMHO sealed tanks are the best option. Fit large inspection ports so you can dry them out and have access to under deck etc. The important place for buoyancy is under the decks ie near the chines (if it had chines) This is the area where your buoyancy provides the righting force when you heel. Any water sloshing into the sides of the hull negates this righting power. Of course you should seal off the bow and stern compartments simply because it is easily done. But it is under side decks that is important. Unfortunately this all might leave you with effectively a small foot well cockpit that is not buoyancy tank. In which case you might consider raising the floor to a self darinig cockpit. I never did like those venturi drains. As you have found they are no good if you stop sailing.
Of course all these ideas will reduce the sailability factor if it is to be raced. But enhance the value for cruising. Around here a Flying Fifteen too old to race competitively has no value at all. I am aware of 3 given away. Which is really sad for a fine GRP keel boat. Just needs a sealed cockpit and perhaps a tiny cabin.
These mods could make it suitbale to be left in the water and far more suitable for cruising with a light crew and stronger winds. good luck olewill

 

[oldsaltoz]

Get yourself a few pool sticks, they are closed cell foam and have been used under the decks of small power boats to keep them afloat if holed.

Good luck and fair winds.

 

[Alan_B]

The rear tank is certaintly grand as it is, the front I could probably squeeze some more bottles into around the bags. Actually I can probably get a load of empty 5L PTFE jerry cans from my work instead of them being destroyed. Plus I could go with a bag infront of the mast (under the deck).

Ill maybe just go with side bags if I can get hold of some cheap enough. We are sailing on a budget at the moment, but at the end of the day I dont want to risk the boat.

She is certianly old, has seen better days, and is worth very little but its great fun, and being my first boat she will probably always have a special place in my heart. They are an absolutely stunning looking boat. I knocked about a seaside town in my younger days and there was a load of them always out at the marina and always loved the shape of them. Certianly in the future I will look into upgrading to a small cruiser/racer along the lines of an Achilles 24 or similar, but for now we have to make do with what we have.

The reefing point in the main is an excellent point, I shall make a few phone calls. It could definatly save a repeat performance of Saturday.

 

[TradewindSailor]

I think the reefing option is a good one. As rigged they are a serious racing boat requiring experienced hands to sail under control. I don't think it will be long before you will learn to control it, but while you learn reefing is a good idea.

I used to race these back in the 90's. There were in effect two classes ..... one for the old boats and one for the new; as the older ones were no longer competitive with the Ovnis. This meant that the older boats still had value ....

 

[knuterikt]

Have you checked http://www.flying15.org.uk/ ?

I have an Andunge built in wood, but they have also been built in GRP (most).
The Andunge class association has updated the class rules to require added buoyancy to the wooden and older GRP boats to prevent from sinking when it get filled with water.
We are not allowed to start a race without complying to this safety rule.

For the wooden boats like mine the recommended solution is to shape closed cell blocks and place/secure these under the for and aft deck.

If your closed cell blocks will be exposed covering it with fiberglass/epoxy before strapping it in place could work.
Looking at http://www.flying15.org.uk/news/weight-reduction-program- is seems weight is an issue on these boats?

 

[Iain C]

Hello and welcome to the forum.

I'm currently restoring a very old 15, a 1963 Souter boat, and she has bags...2 in the bow tank, 2 in the stern, and 1 under the side "tanks" in the back of the cockpit. There's a thread on this forum covering it.

If you fit bags, one of the critical things is to make sure the underneath of the decks is smooth, the last thing you need is an errant nail or splinter puncturing the bag just as its needed! I've actually glued pipe lagging underneath all the deck frames.

Might be worth giving these guys a call. They got some second hand 15 parts in and did me a good deal on a more modern rudder to replace the vertical shaft one on my boat. They did have a set of bouyancy bags on eBay a month or two ago but not sure if they sold... http://www.versatilemarine.co.uk/

Lastly is your boat a chute boat? If so do you have a sailcloth cover to keep the worst of the green stuff from disappearing down the chute?

Good luck!

 

[Alan_B]

Have you checked http://www.flying15.org.uk/ ?

I have an Andunge built in wood, but they have also been built in GRP (most).
The Andunge class association has updated the class rules to require added buoyancy to the wooden and older GRP boats to prevent from sinking when it get filled with water.
We are not allowed to start a race without complying to this safety rule.

For the wooden boats like mine the recommended solution is to shape closed cell blocks and place/secure these under the for and aft deck.

If your closed cell blocks will be exposed covering it with fiberglass/epoxy before strapping it in place could work.
Looking at http://www.flying15.org.uk/news/weight-reduction-program- is seems weight is an issue on these boats?

I have had a look on there, and have read the class rules. We are only club racing at the monment with cruisers and a hawk 20, our 15 fleet is out in winter for an 'ice breaker' series. As far as I know we conform with the minimum requirement, but as mentioned I suspect our boat is probably a bit heavier than it should be.

Good call about using foam and just coating it rather than sheeting it in. Cuts down weight, volume of byouancy can be maximised and its quick and easy.

Hello and welcome to the forum.

I'm currently restoring a very old 15, a 1963 Souter boat, and she has bags...2 in the bow tank, 2 in the stern, and 1 under the side "tanks" in the back of the cockpit. There's a thread on this forum covering it.

If you fit bags, one of the critical things is to make sure the underneath of the decks is smooth, the last thing you need is an errant nail or splinter puncturing the bag just as its needed! I've actually glued pipe lagging underneath all the deck frames.

Might be worth giving these guys a call. They got some second hand 15 parts in and did me a good deal on a more modern rudder to replace the vertical shaft one on my boat. They did have a set of bouyancy bags on eBay a month or two ago but not sure if they sold... http://www.versatilemarine.co.uk/

Lastly is your boat a chute boat? If so do you have a sailcloth cover to keep the worst of the green stuff from disappearing down the chute?

Good luck!

Yep we have a chute and it has a cover on elastic so it snaps back to get the spinny up. I did notice than even though it was closed on saturday it wasnt stiff enough and collapsed in so there was a fair bit of water getting in there too.

Im constantly making mental notes of things to adjust and sort out, so slowly the boat is improving and we are definatly getting quicker. So if I can get her to the point where if we flood it we dont need assistance I'd be quite pleased.

 

[knuterikt]

I have had a look on there, and have read the class rules. We are only club racing at the monment with cruisers and a hawk 20, our 15 fleet is out in winter for an 'ice breaker' series. As far as I know we conform with the minimum requirement, but as mentioned I suspect our boat is probably a bit heavier than it should be.

Good call about using foam and just coating it rather than sheeting it in. Cuts down weight, volume of byouancy can be maximised and its quick and easy.

If they have put something in the rules or recommendations for this boat you would have a tested method of getting enough buoyancy in the correct spot. I sounds a little bit strange if you cant find any recommendations that have already been tested.

But if you have to start from scratch..
The goal of adding buoyancy to a boat like that is to give you a stable platform so you can start bailing or at least prevent the boat from sinking under your feet.

The flotation elements must be placed as high as possible, evenly spread so the boat float on even keel (taking the CG into consideration)

If you start by cutting blocks of foam and strap them temporarily in place you can fill the boat with water and test, select a spot with shallow water.

When you have found the required volume, placement and shape of the buoyancy make it permanent.

You can calculate the needed volume and placement but for a small boat like this practical testing is faster...

Edit:
Why not try to contact one of these http://www.flying15.org.uk/uk-association/committee-details and ask for advice?