Mast Ram

[Stuart Watts]

New IOM owner here with a Fatboy design hull. I'm slowly getting my head around the different rigging adjustments. However, I am not sure about the mast ram.

My rig has a slotty mast (although it doesn't have a slotty sail (!) just string luff rings through a luff wire in the sail.) The mast sits in a mast step hole about 60mm deep. The deck infront is higher and has a threaded rod through a hole with a large plastic knob on to adjust the amount of backwards ram. However my mast sits at the back of the step hole so the ram is not being effective. Is there a wedge or something to push the mast forward with pressure from the ram to bend it back? At the moment the ram does nothing. The mast is reasonably straight (negligible pre bend) and the sails seem to have about + 5mm luff curve. Am I missing something?

[Eric Finley]

Hi Stuart, welcome to the World of IOM's.

My first suggestion is you take a look at  this web site:- https://www.nigelbarrow.co.uk/

You will find a large amount of information regarding rig/boat setup.

If the mast is as far back in the mast recess slot I would expect the boat when sailing would not be balanced. The position shown on the photograph would probably mean you have far to much mast rake. Try shortening the forestay so that the mast is reasonably upright when it is centred in the mast slot (adjust ram so it holds mast in this position) as a start point. The backstay tension will firstly straighten any pre-bend in the mast and then bend the mast towards the stern to match the luff curve. with the tension applied the mast should start to press on the mast ram.

If you are sailing at a club that races IOM's I would ask one of their experienced Skippers to look at your setup and advise you as it is easier to show a setup than try to describe.

Where are you based?

I'm sure much more experienced skippers will be along who are far more literate at describing what you are trying to achieve.  

Eric

[RoRo]

Brad has written some very helpful information here

http://www.bgsailsanddesign.com/uploads/7/0/6/9/70698521/bg_sails_rig_tuning_iom.pdf
 

there is a wealth of information on his site so a fantastic place to look

 

 

[Stuart Watts]

23 minutes ago, Eric Finley said:

Hi Stuart, welcome to the World of IOM's.

My first suggestion is you take a look at  this web site:- https://www.nigelbarrow.co.uk/

You will find a large amount of information regarding rig/boat setup.

If the mast is as far back in the mast recess slot I would expect the boat when sailing would not be balanced. The position shown on the photograph would probably mean you have far to much mast rake. Try shortening the forestay so that the mast is reasonably upright when it is centred in the mast slot (adjust ram so it holds mast in this position) as a start point. The backstay tension will firstly straighten any pre-bend in the mast and then bend the mast towards the stern to match the luff curve. with the tension applied the mast should start to press on the mast ram.

If you are sailing at a club that races IOM's I would ask one of their experienced Skippers to look at your setup and advise you as it is easier to show a setup than try to describe.

Where are you based?

I'm sure much more experienced skippers will be along who are far more literate at describing what you are trying to achieve.  

Eric

Thank you Eric! all really helpful! I am based in the midlands sailing at Hollowell RC Sailing Club. We have a few very experienced sailors - who I will ask.  My boat sails quite well balanced with the mast rake/set up as it stands. The Jib leech, however,  seems to be too open when set with little or no topping lift applied. I had thought this was an issue with the jib pivot point, but I will review the information in the web site you detail and see if anything jumps out, and if changing the rake a bit may help the jib leech as well as the mast ram situation. Really appreciate you taking the time to help me. Thanks! Stuart

[Stuart Watts]

15 minutes ago, RoRo said:

Brad has written some very helpful information here

http://www.bgsailsanddesign.com/uploads/7/0/6/9/70698521/bg_sails_rig_tuning_iom.pdf
 

there is a wealth of information on his site so a fantastic place to look

 

 

RoRo, It does indeed seem to be a great resource. I will study it closely. Thank You! Stuart

[John Ball]

You mention jib leach open with little topping lift. This is also related to a lack of prebend. With prebend, the backstay puts tension on the forestay, and that upward force on the jib boom at the tack, creates a downward force on the clew - and that will tighten the jib leach and topping lift.

John

[Eric Finley]

Stuart

For my own interest is this a FATBOY designed by David Alston?

If it is Measured the designer's name and builder's name will probably be listed on the Certificate.

Eric

[Stuart Watts]

11 minutes ago, Eric Finley said:

Stuart

For my own interest is this a FATBOY designed by David Alston?

If it is Measured the designer's name and builder's name will probably be listed on the Certificate.

Eric

Eric, I have investigated with the IOM registrar but we cannot find it has been registered. I have no certificate. This old web address refers to the maker (pictured) but not named. They obviously made somewhere about 35 of this design finishing in 2010.  Mine is exactly as the one in the picture. https://fatboyyachts.wordpress.com

[Stuart Watts]

54 minutes ago, John Ball said:

You mention jib leach open with little topping lift. This is also related to a lack of prebend. With prebend, the backstay puts tension on the forestay, and that upward force on the jib boom at the tack, creates a downward force on the clew - and that will tighten the jib leach and topping lift.

John

Thanks John, it certainly sounds like I need to look at the mast rake/pre bend. Thanks for your help! Stuart

[Eric Finley]

Hi Stuart

If that is the case, it is a David Alston yacht. Unfortunately he is no longer with us. As the site states there were quite a few hulls built.

David was sailing one at our club on and off in approximately 2011/12 before concentrating on a Isis mk 2 designed by Barry Chisam for a few years. (With reasonable success.) He actually assisted with my introduction to IOM sailing.

If memory serves the Fatboy was water tank tested. David was involved with large vessel specification and acceptance testing of supplied boats as his day job.

David's own UK Fatboy was sailed in its roar state (no paint so translucent). I believe he also sailed a painted version in Holland. The mould for this design was sold upon David's demise, not sure who purchased it.

Eric

[Stuart Watts]

19 minutes ago, Eric Finley said:

Hi Stuart

If that is the case, it is a David Alston yacht. Unfortunately he is no longer with us. As the site states there were quite a few hulls built.

David was sailing one at our club on and off in approximately 2011/12 before concentrating on a Isis mk 2 designed by Barry Chisam for a few years. (With reasonable success.) He actually assisted with my introduction to IOM sailing.

If memory serves the Fatboy was water tank tested. David was involved with large vessel specification and acceptance testing of supplied boats as his day job.

David's own UK Fatboy was sailed in its roar state (no paint so translucent). I believe he also sailed a painted version in Holland. The mould for this design was sold upon David's demise, not sure who purchased it.

Eric

Thanks Eric, I hadn’t been able to find much about the boat/designer. I found the fat boy logo in the fibre glass mat inside but not much other than that. This boat was in poor condition at the hull/deck join and I have re glassed it there to repair and strengthen. It seems to have potential but need to get it tuned right I think!

[LaurieB]

10 hours ago, Eric Finley said:

Hi Stuart

If that is the case, it is a David Alston yacht. Unfortunately he is no longer with us. As the site states there were quite a few hulls built.

David was sailing one at our club on and off in approximately 2011/12 before concentrating on a Isis mk 2 designed by Barry Chisam for a few years. (With reasonable success.) He actually assisted with my introduction to IOM sailing.

If memory serves the Fatboy was water tank tested. David was involved with large vessel specification and acceptance testing of supplied boats as his day job.

David's own UK Fatboy was sailed in its roar state (no paint so translucent). I believe he also sailed a painted version in Holland. The mould for this design was sold upon David's demise, not sure who purchased it.

Eric

After David passed away his Fatboy mould went to Doncaster MSC who were planning to use it to make some Club boats for new members and Club level racing. (be interesting to know if this was ever progressed)

Cheers

Laurie