Arwen's meanderings

Hi everyone and welcome to my new blog. My name is Steve and i am the lucky owner of a John Welsford designed 'navigator' named Arwen. I built her over three years with the help of my father, father-in-law and two children. She was launched in August 2007 at Queen Anne's battery marina in the barbican area of Plymouth. This blog is a record of our voyages together around SW England.
Arwen has a YouTube channel of her own. Search "plymouthwelshboy".






Monday, 16 April 2012

too much weight on the end of dinghies

Recently someone commented about having the anchor up front and all that weight on the bow and then all the weight of the outboard on the transom being another issue. I don’t know enough about sailing boat design or sailing physics but the advice came from someone very knowledgeable and as close to an expert on dinghy sailing as there can be. Consequently I was worried and so went in search of some clarification from other people I know who know lots about this kind of thing; namely JW and his forum members and my friend Dave.

is this the best place for the main anchor on Arwen - discuss!
My friend Dave, as always,  made a number of valid points, based on decades of sailing experience in small boats. He said it was all about balance, trim and stability. (Ha! I vaguely remember those being mentioned on RYA courses ). If plodding around the sound, then the outboard on the back isn’t a problem. If off on a longer coastal passage with a following sea then it might be prudent to unship the outboard and store it alongside the centre case low down. This would of course depend on location...going around a headland; the danger of a lee shore etc would all have to be factored in – how fast can you reattach an outboard in a following sea and get it started? Basically, if the stern doesn’t seem to be lifting in a following sea, then unship the outboard. Now I'm really glad I installed those securing straps for the water ballast containers a few weeks ago because they could actually retain an unshipped outboard quite securely.

My friend also observed, from personal experience of helming my boat, that Arwen is a pretty large and heavy dinghy and so carries the outboard well in most sea conditions that I sail in and since I don’t sail in anything much above force four, it should be fine.


should I leave the outboard on the transom permanently during my sailing as I do...or should I unship it and store it low down against the centre case until needed - discuss!

He did prompt me to think about what anchor I carry on Arwen. Is it appropriate for the type of sailing I’m doing that day? A picnic stop in Cawsand needs only a moderate hold as opposed to the grip needed for an overnight anchorage. What are the weather conditions – onshore winds and swell? In that case I may need a heavyweight anchor which ideally should be deployed amidships and low down so that balance and stability are not affected. He also thinks that on long trips I should stow it as I’ve done before in the bucket amidships. He finished by posing some really useful questions (as he always does):

What is the intended sailing area?

What is the sea state in which I will be sailing?

What will the weather conditions be during the trip?

Where will I intend anchoring?

How secure does anchoring have to be – lunch time; afternoon loll or overnight?

What if it goes wrong – what is my plan B?

exactly what size anchor should my main anchor be - JW seemed to think this one was about right


John W also had words of wisdom, as always, based again on decades of sailing and design experience. He agreed that weight at the ends means inertia in the ends. He painted this image:

Imagine a bar with two weights on it that can be positioned anywhere on the bar. Rotate the bar holding it in the middle with the weights in the middle. Try and stop the rotation. Then imagine doing the same thing with the weights at the end of the bar. Much more difficult to stop the rotation”!


He went on to observe that fast deployment of the anchor basically requires that the anchor is on the bow, unless the anchor is small and light enough that you can easily heft it overboard from amidships and that boat balance was often a matter of compromising without losing safety.


that's where I used to store my bigger anchor - in that grey large bucket
the smaller anchor is in the blue box on the floor in the port side of the front cockpit area


Like my friend Dave, John and Pete, another forum member, (who has given me much sound advice in the past) felt that if the outboard was light enough to mount on the transom when needed then that might be a good solution. Everything of weight that can easily be put in the centre of the boat (chain, fuel, water, tinned food, outboard etc.) should be put there, but eventually it is a matter of  my judgement.
Pete finished, much like Dave, by saying

“If you find that the bow is submarining in bad weather or that waves are coming over your stern then your boat has probably got too much weight in the ends and/or it is overloaded”.


Wise words and a clear message here. Have your wits about you and keep checking balance, trim and sail area aloft; and sea state and direction, if the weather turns!

John made a final reassuring point.

“Navigator is designed to take up to 20 kg of anchor and chain up forward in the anchor well. The volume in Navigators hull is so distributed as to take into account the various weights required, and the positions in which they will be stored and no, you will not have made her unsafe. Note that she is designed from first principles as a cruising sailing dinghy, whereas most of the boats that people often use as cruising dinghies are [more] general purpose boats adapted for the purpose.”


as I remember that is a 12 kg anchor with around 4 kg of chain but I will need to check

It is good to have people around to help you work things through. My thanks, as always, to Roger, Peter, John and Dave for giving up their time to educate me further about small boat sailing intricacies. I appreciate the advice and time you gave gents....thank you.

Steve

6 comments:

Joel Bergen said...

I think it's impractical and very dangerous to remove an mount an outboard at sea.
JohnW designed Navigator to carry an outboard, so no worries there.
Unless your anchor really heavy, I still don't think it will make a noticable difference if it's stored in the anchor well or in the cockpit.
I can tell you for sure my Navigator sails much better when I add some weight forward. Granted, I am a heavy guy. The combination of my weight and the outboard drops the stern and raises the bow on my Navigator, which causes the bow to slap in chop. When I add weight forward, all that goes away and the boat sails faster and noticably smoother.
Buy your mileage may vary, as they say. You're not as big as I, and I can see that you carry a lot more gear up forward than I. In your case, I think experimentation is the key.
-Joel

steve said...

I think you and I think alike; the outboard temporarily stowed makes me nervous; trying to mount it whilst out at sea even more so. I have had to refill out at sea and dangled outback with funnel and jerrycan whilst hove to is not for the faint hearted; so trying to lift over and secure an 18 kg outboard - um!!

I find Arwen seemes to sail best when weight is up front to counter outboard weight and I sit on forward centre thwarts; that's why I added a tiller extension; I tend to move sternwards when sailing downwind and as as far forward as comfortable when going windward; i try to distribute weight equally each side where possible although there is more weight on starboard side due to well and outboard. up wind heading to port with wind off starboard and she seems fine; upwind with wind coming from port - she does lean a little more over but then and you need to exercise a little more caution and alertness to wind shifts and gusts.
does this make sense?

Steve

Joel Bergen said...

Hey Steve,
I have this idea for safely refueling outboards with integral 1 liter gas tanks. Haven't tried it yet but I think it might work well. Obtain several empty one quart or one liter bottles. Used automobile motor oil bottles would be ideal. Fill them with gasoline (or petrol). When your outboard runs out of fuel, pour the entire contents of a bottle to refill the tank. No measuring. No spills from overfilling. Lightweight enough to pour in one-handed. The shape of the bottle is even designed for proper pouring. Carry as many as you need. What do you think?

steve said...

there are days when I realise how really dim I am and the phrase 'now why didn't I think of that' runs through my head constantly.......we have special camping stove fuel bottles over here which are not too expensive and which hold a litre of fuel perfectly and actually they are easier to store in lockers

Doh! I'm suffering a 'homer' moment
Good idea Joel!!!!!!!!!!!!!
Thank you!

steve

Joel Bergen said...

I don't think anyone has thought of it. I've been searching all over for some king of 1 quart gasoline bottle but haven't found one yet. You'd think the outboard motor manufacturers would offer an accessory like that, or some way to hook up an optional external gas tank but it appears not.

steve said...

i think in litres and the biggest fuel bottle we can get is 1.5 lt which I ordered today. That will be plenty and much better than the five lt jerry can and funnel I use!!

steve