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Len
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Senior Requests

Postby Len » Sun October 8th, 2006, 2:53 pm

Hi All,

From other posts on the forum, I get the impression that the Senior suffers from excessive weatherhelm. Could anyone confirm that ?

If anybody has fitted a skeg, it would be interesting to know how much lateral area it has and what effect it had on handling ?

From the drawings, I get the impression that the Senior Mk 1 (CB) is possibly rather tender. The centre plate can only weigh around 32 Kg and is not very deep. Yes, I know that is not the only factor, but ...
If I decide to build a Senior, I am considering adding an external balast keel with a slot for the CP. I am not keen on bilge keels. An efficient centre board, perhaps a bit deeper and with a little balast near its bottom (say 20kg) should be a lot better.
Any comments, please ?

A mod. to the Senior's sail plan is mentioned but I can not find it. Could someone please point me in the right direction ?

It would be nice to just hear what a few Senior owners think of their boat ?

The most difficult question, I have to ask myself : What will I do with it if I build one ? Down here in Bayern there is nor much water. Around 1960 my brother and I built a YM Heron and sailed it on the Deben, mostly. When I found the EOG had the drawings, I think I must have imagined me doing that again, living on the boat. All very romantic, but hardly possible. Since getting the Senior drawings earlier this year I have built a Mouse pram to Iain Oughtred's design. Now painting. I must say I like Mr. Oughtred's work a lot.

Many thanks for any info.
Len.
Leonard_Woods

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Postby Eventide Owners Group » Thu October 12th, 2006, 11:56 pm

Come on Senior owners speak up!

I can tell you Len that you are right about the centreboard version being a bit on the tender side! It has to be sailed like a dinghy, but on the plus side it will float in a puddle!

Many Seniors have bowsprits to offset the weatherhelm, that seems to work, I have seen one or two bilge keelers fitted with small skegs too, cannot do that on a centreboarder of course!

Hopefully others will come forward with details on the Gaff rif so many adopted. Looks pretty too!

John
Eventiders
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chris s
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Postby chris s » Sun October 15th, 2006, 12:41 am

After owning sailing a wooden bilge keel Senior for a couple of seasons I decided to build a replacement hull and deck in GRP,
At the same time I threw away the bilge keels and increased the depth of the centre keel by 1 foot (30cms ish) and the length to 8 ft, the keel is 4 inches wide,
this gave a volume of 2.66 cu ft and an increase in bouyancy of approximately 140 lbs in salt water,
as the weight of the standard cast iron ballast keel is 160 lbs this meant I could (and did) increase the weight of the ballast keel to (just over) 300 lbs
I cast this in lead and hung it on the bottom of the extended keel, the results were even better than I expected, no more sideways sailing and getting rolled everywhere,
for the first time ever she would actually point and sail to windward,
and when I was caught out in a gale on the way to the Isle of man, she hove to beautifully and was so stable we actually made hot drinks, cooked a meal, then later on setting the storm jib and with 2 reefs in the mainsail we ran south before the wind all the way past Puffin island and on into Beaumauris, A distance of about about 50 miles made in not ideal :twisted: conditions, which little boat handled with ease.
Last edited by chris s on Sun October 15th, 2006, 12:53 am, edited 2 times in total.

chris s
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Postby chris s » Sun October 15th, 2006, 12:50 am

On recollection, I actually won the old EOA 1991 or was it 1992 Maiden voyage trophy for that IOM trip,
Hmm it must have been a quiet year on the maiden voyage log competition front :lol:
John, Do you still have a copy of my log from that trip? I know it (or a part of it) was published in the relevant EOA Bulletin.

Len
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Joined: Wed September 27th, 2006, 1:06 pm
Location: Kösching, Germany

Postby Len » Mon October 16th, 2006, 5:15 pm

Many thanks for the helpful replys to date. I am hoping to get a few more, especially relating to the centre board/plate version. Please.

I do not really want a deeper keel, if only because it would be more difficult to get it on and off a trailer. I am/was hoping the Mk2's 160 lb balast keel combined with an efficient centre board would make a good comprimise. It looks as though the boat would still be rather tender. ??

Does anyone have any experience of foam filling to provide buoyancy in the case of being swamped. It would be nice to build in enough reserve buoyancy to float the boat, with balast keel, gear and crew when full of water. Some of this could be got by filling the space under the bunks and floors. Any comments , Please ?
Leonard_Woods

chris s
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Postby chris s » Tue October 17th, 2006, 12:00 pm

1) With foam bouyancy you lose valuable storage space, which on a Senior there isnt that much of to start with.

2) The foam must either be bonded in or securely fastened otherwise it will just float away and over time most foams tend to absorb moisture, which can cause the dreaded rot

3) There just isnt enough space to fit the amount of foam you would need to give positive bouyancy, dont forget you do not want the foam mounted low down in the hull as this will help the boat to float on its side or in the worst case upside down :(

btw, I would estimate the weight of a loaded for sailing Senior fitted with the 160 lb ballast keel as about 1/2 a ton or 500 kilos ish

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Log?

Postby Eventide Owners Group » Sat October 21st, 2006, 3:25 pm

Hi Chris, I have all the old magazines and from time to time dip into them to bring out articles, I will have a search and find it, worth reprinting!

I am going to reprint many of the old articles as so many of the authors have now joined us!

Numbers up to 450 now! amazing isn't it!

Agree with what you say about bouancy, it has to be high or the boat might turn turtle.

I would say the best compromise would be the ballast keel with a slot in it for a plate, then you would have the low draft to get onto a trailer and the sailing ability of the deeper centreboard when down. The ballast would allow you to sit in rather than sail it like a big dinghy.

I know this is not on the plans, but it seems a natural progression. Maurice said the Eventide begged for a slot in the ballast keel and one of his 'L' shaped centreplates.. Just needs someone with the bottle to do it!

cheers,

John
Web site Coordinator

Len
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Location: Kösching, Germany

Postby Len » Thu October 26th, 2006, 1:03 pm

Hi Chris and John,

Many thanks for your contributions.

Re foam filling:
The real reason I asked was because I had a suspicion it might not be good for the wood. I have now dropped the idea. I have heard it being used by "off shore dinghy" sailors, both for buoyancy and protection in case of a collision. Perhaps they dont worry too much about long boat life.

Re bouyancy:
I think it is by no means impossible to get enough buoyancy to float a Senior. I realised that filling the under-floor space would only be a part of what is required. More could be got from:
1. making the frame on station 1 into a bulkhead
2. making the 3 cockpit lockers water tight
3. adding a "bridge locker" i.e. fitting the engine locker of the Mk.2
4. dont forget the wooden structure will supply 30+ Kg of reserve.
Just a thought: if the hull was foam filled upto the actual WL , that would float it.

I now think providing reserve buoyancy would only be really required for an unbalasted CP Mk1 Senior as I think it would be quite easy to capsise one of those, though I never did capsise my YW Heron dinghy.

Re balast keels:
Earlier I was considering a balasted dagger board. It has many advantages: Aerodynamic efficiency; close fitting slot is possible; no extra skin drag from an external keel; big righting moment for smaller weight. BUT what happens if you hit a sand bank with the keel down ?

I will, at some time, make drawings for a slotted keel and a new CB.
The holding factor is I would like to (must) know how far, if at all, the lca can be moved aft. That is why I asked about weatherhelm at the beginning. How much skeg area ? How long a bow sprit ? If I had these I could calculate where the c of area of the balast keel and CB should be.
The new CB/CP will probably be longer than the original and so extend further aft into the cabin. Not good but has to be. (?) But would be more shallow and pivoted in the balast keel.


I have looked around in books and the internet for other mini (16 ft) cruisers but have yet to find one which pleases me so much as the Senior.
Most of it is "just right" for me. Just big enough, not too big and it looks like a real boat, not like a plywood box. Having said that, I must say I an very impressed by the work of Mr. Bolger et al. I wish I could be that creative. But I still want a boat that looks like my idea of one.

That is enough from me for now.
Regards,
Len
Leonard_Woods

alkorn
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Similar questions from another possible builder

Postby alkorn » Fri January 5th, 2007, 12:27 pm

Like Len, I am thinking about building a Senior and have questions concerning helm balance and lateral plane. Rather than start a new thread, I thought I should join this one.

Concerning helm balance:

The consensus seems to be that the Senior as designed has too much weather helm, but that adding a bowsprit about 2 ft. long and increasing foresail area to match will give good balance. Agree? Disagree?

Concerning lateral plane:

Chris S. says that the bilge keel Senior has unacceptable leeway. Others seem to be happy with the design as it is. How bad is the leeway on the bilge-keel boat? (I realize that unless you've performed careful experiments any replies will be quite subjective.)

How about the centerboard version? Will it stay close on the wind?

All input will be appreciated.
Al Kornhauser
Blacksburg, Virginia, USA
alkorn@vt.edu

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Fiddler's Green
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Weatherhelm and ballast

Postby Fiddler's Green » Sat January 13th, 2007, 10:23 pm

Yes the Senior did have weatherhelm, but the inclusion of the short bowsprit cures it. It also allows the flying of all important light weather sails, so should be considered as standard really. A small skeg, about 9" fore and aft measurement under the hull, tapering to 6" at the bottom helps as well. Steel and galvanised it protects the rudder too.

The best keel set up was fitted to Martin Lewis's Senior 'Pau Amma' It had the bilge plates extended some 6" deeper and it sailed well. Sadly the new owner had no idea of the importance and worth of the keels and has removed them on this boat and fitted a centreboard because they wanted an easy launch boat.....

The Centreboard boat has to be sailed like a dinghy, but does go better upwind.

Chris's modification works well too, but then it depends where you moor!

This deeper bilge keel modification was the last sanctioned by the designer Kenneth Gibbs before he gave up boating!

Regards,
John
Proud owner and builder of 'Fiddler's Green'

martinchaplin
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Postby martinchaplin » Tue March 18th, 2008, 4:41 pm

Hello all,
I am new to this forum and I am considering building a Senior. I was just reading the posts about calculating center of balance etc. Here is a link that you may find useful to calculate where the center of balance is for a particular rig. Might help you to decide where to place the centerboard.

http://home.clara.net/gmatkin/bd_sailcalc.html

I hope this helps.
I would also like to hear a lot more about sailing experiences with the Senior in various wind conditions etc.

One of the things I notice is that the boat is built very heavy compared to other boats of this size. As far as I can tell it uses 9mm ply for the hull. So the question is could a lighter hull be built using 6mm ply and the weight saved put into the balast keel? Would this have a significant affect on her stability? Or would the strength of the hull be compromised?
Kind regards,

Martin

Len
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Postby Len » Mon March 24th, 2008, 12:13 pm

Hi Martin,
Yes the Senior is very heavily built. Add to that 9mm (3/8 in) ply seems hard to get. I have done detailed weight calculations for a slightly modified version (MK 4?) using 10mm ply. Even then I could increase the balast to 90 Kg. If I really do build one it will be this one and I would use 8 mm Mahogany ply (Dutch - Bruynzeel - the very best). 8mm is within Dave Gerrs suggestions for a boat of this size and I am sure is more than strong enough. Personally I would not go down to 6mm. Apart from strength of the hull, there would be more risk of handling damage. With 90 Kg of balast it can (theoretically, at least) recover from a 90 deg. knock-down, but I had to increase the width of the side decks in the way of the cockpit to prevent water flooding into the hull - which would have prevented a recovery.
Hope you find this interesting.
Len
Leonard_Woods


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