Work proceeds on this boat at a snails pace but I have a question to ask about bow bumpers. This boat doesn’t have one - just hard, cold white fibreglass. In theory it should have a bumper made from an elastomeric material which in my book is bath silicon or carved from a flip flop but I wondered if a hollowed out squash ball held on with dynema would be acceptable? If so, would you unhook it for measurement purposes and then use said dynema ‘bridle’ to hold it over the very pointy bow??

Many thanks

Simon

I bought some of these to try and solve the same problem on my Tern and other older bumperless boats. https://www.ebay.co.uk/itm/800179175264

8 hours ago, tiggy_cat said:

I bought some of these to try and solve the same problem on my Tern and other older bumperless boats. https://www.ebay.co.uk/itm/800179175264

Did they work and are they class legal??

The formula for rating a 6M doesn't care about length overall, so adding anything at the bows to make a bumper is fine, it is ignored when calculating LWL. The Class Rules require the squishy addition to be at least 13 mm thick, so that shouldn't be a problem either. The extra 20g of foam should not be a problem for displacement, but might be an issue when formed in 50g of bath silicone if the forward waterline ending is right on the edge of where it needs to be.

The tricky bit is whether the boat was ever originally measured, or is eligible to be re-measured, under the Pre-1985 rules, when a bow bumper was not a required component of the boat. I think from 1985 onwards the Class Rules require a bow bumper, and this bumper needs to be in place at measurement (CR 2.2.9 in the 2025 rules, or similar in previous rules). If the certificate relates to measurement under Pre-1985 rules then a bow bumper does not need to be present at measurement. However, I think a bow bumper does need to be in place when racing, removeable or otherwise, both under CR 1.5.3(e) in the 2025 rules and as a courtesy to the other boats in the event.

48 minutes ago, Lester Gilbert said:

The formula for rating a 6M doesn't care about length overall, so adding anything at the bows to make a bumper is fine, it is ignored when calculating LWL. The Class Rules require the squishy addition to be at least 13 mm thick, so that shouldn't be a problem either. The extra 20g of foam should not be a problem for displacement, but might be an issue when formed in 50g of bath silicone if the forward waterline ending is right on the edge of where it needs to be.

The tricky bit is whether the boat was ever originally measured, or is eligible to be re-measured, under the Pre-1985 rules, when a bow bumper was not a required component of the boat. I think from 1985 onwards the Class Rules require a bow bumper, and this bumper needs to be in place at measurement (CR 2.2.9 in the 2025 rules, or similar in previous rules). If the certificate relates to measurement under Pre-1985 rules then a bow bumper does not need to be present at measurement. However, I think a bow bumper does need to be in place when racing, removeable or otherwise, both under CR 1.5.3(e) in the 2025 rules and as a courtesy to the other boats in the event.

Thank you Lester. Firstly this boat hasn't been measured. Originally I was thinking of taking a hacksaw to the boat to remove a piece maybe 4- 5cm long and at least 13mm at deck level and roughly following the taper of the profile to make a mould for bath silicone. Using a rubber 'power ball' might be a much easier way to achieve the same effect without touching the hull and I have see that kind of thing on 6's and A's from time to time. I do feel though that having a bumper of some sort is pretty much an essential to be properly sociably responsible when sailing with others, irrespective of class rules.