Common fit challenges
From the Rocna Knowledge Base
This section outlines some of the common fit challenges which Rocna owners can come across when attempting to install the new anchor on an older vessel, the bow-roller of which is designed perhaps for a specific anchor type and size. Some of these problems are common, and there can be simple and cheap solutions in many cases.
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Issues with the roll-bar
The roll-bar on the Rocna can unfortunately represent a problem with certain roller designs, if the roll-bar should clash with a forward projection such as a bowsprit, or the underside of a platform.
Bowsprits
This is an issue with some sailboats, if their anchor bow-roller(s) are designed as part of the bowsprit arrangement. Many yachts with bowsprits incorporate a roller directly next to the 'sprit itself. A Rocna, with its roll-bar, cannot fit in such a location. Moreover, the whisker and bob stays can present an additional challenge.
A new place for the anchor
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Lowering the roller
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Moving the roller to the front of the 'sprit
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Platforms with enclosed rollers
This is an issue with some powerboats, if their anchor bow-roller(s) are embedded and enclosed in a forward projecting platform. A Rocna, with its roll-bar, may not be able to be pulled home completely, should the roll-bar strike the underside of the platform earlier than desirable.
Without modifications
A possible solution may be to simply accept the attitude in which the anchor finds itself; it may be acceptable if not ideal. This depends on how far the anchor can be retrieved, and if its final position can be made stable. For example, Bill Parlatore, editor of PassageMaker magazine, uses a Rocna 25 on his powerboat Growler. As shown in the photo, the anchor does not sit as well as may be thought ideal. Nonetheless Bill is happy with this arrangement, and the anchor self-launches and comes home without problem.
(For more photos of Bill's anchor set-up, please read the PassageMaker review of the Rocna).
Lowering the roller
Dropping the anchor downward so that the roll-bar is positioned just directly below the platform is one of the easiest and most elegant solutions. It also has the advantage that weight is slightly lowered, always a desirable outcome on any boat.
The idea is to position the primary roller lower than the positioned drawn by the original designer. Typically, rollers are placed inline with the platform itself, to accommodate a specific plow or claw type, and it is this situation where the Rocna is likely to present problems.
The new roller will need to be positioned lower by adding cheek plates, or extending any existing ones, below the platform. Frequently a second roller will also be required in order to handle the changed route for the chain, and to help position the anchor in the correct attitude when it is pulled home. These rollers and the cheek plates would ideally follow the guidelines presented in the Bow roller assembly design section.
The concept drawing on the right shows a possible solution for the anchor platform on a Selene 59. The original design was intended for plows, and incorporated dual rollers on a pivoting assembly. The pivot is unnecessary with the Rocna self-launching design.
Moving the roller to the front of the platform
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Customizing the platform to accept the roll-bar
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Pins and retaining bolts
Existing rollers may feature retaining pins designed to fit through a hole in the matching anchor, or over-the-top bolts or latches designed to both secure the anchor when home and chain when deployed. The shank on the Rocna is relatively tall when compared with some other anchor types, particularly CQRs (articulated plows). This may require modifying the pins, or removal altogether.
Moreover, please note that we advise against the use of through-shank retaining pins. For more, please consult the Anchor retainment section.
