Stainless Steel Boat Fittings

Deck fittings

Marine 316 stainless steel is the standard “marine grade stainless steel” with excellent weldability. Marine tubular fabrications like bulwarks and handrails have to fastened to decks and cabins in a manner to avoid structural degradation with time due to corrosion and stress. The correct method of fastening the stanchions, pulpits, and other handholds and lifelines to the deck and superstructure of the boat has to be subject to a means of checking their condition.

All of these vitally important stainless steel boat fittings should be bolted through the hull. Fibreglass hulls should be reinforced with load spreading plates beneath the fittings to help to brace the anchorage point against sudden severe loads.

All fastenings should be designed and fitted with the safety of the crew in mind, and should be strong enough to support the weight of the heaviest crew member. They should be included in the list of deck fittings to be inspected regularly, and tested annually.

Handholds

Handholds should be bolted through the deck or cabin-side, with load distributing pressure pads fitted where necessary. Pressure pads, washers, and outside flange fittings should be bedded in sealing compound. Bolts should be free from corrosion and drawn up tight.

For testing handholds should be tugged away from the anchorage point and rocked sideways. Slight give is likely. Excessive movement should be corrected by tightening bolts or renewing compound. Evidence of cracking at the bolt holes in a fibreglass skin should be noted, and larger load spreading plates fitted.

Wooden handholds must be bolted and bedded in sealing compound, with pressure pads fitted where necessary.

Handles should be inspected for splitting. Discard split or broken handholds, and make and fit new ones. Smooth rough edges with a rasp and sandpaper. Finish with varnish.

Corrosion in the bolt fastenings is common with wooden handholds. Withdraw and inspect a sample bolt at the end of each season.

Guard rails

Stanchions should be substantial, and spaced not more than 7 feet (213 cm) apart. Anchorage plates must be throughbolted to the deck, or to the deck and hull, with load spreading plates where necessary. Fibreglass decks should be protected with a pressure pad beneath the anchorage point where the base flange is less than 2 inches by 3 inches (50 by 75 mm). Anchorage plates should rest on a bedding of flexible compound that will prevent water penetrating the hull and corroding the bolts. Withdraw sample bolts annually. Corrosion of galvanized bolts is easy to assess. Marine 316 stainless steel bolts should be held by the head in a vice and bent, to check for crevice corrosion.

Drain holes in the bottom of an anchorage point should be clear. Welding should be inspected for fracturing and cracking. Clevis pins or bolts should be fitted to hold the stanchion in the anchorage plate. All must be made of compatible metals, with no excessive corrosion. Stanchions should be straight and free from corrosion – look particularly carefully at the point where it rests against the top of the anchorage plate. Apertures to hold the lifelines should be smooth and bushed if necessary, so that wires are not kinked or worn.

Stanchions should be designed to withstand severe and suddenly applied loads. Test them when you have the opportunity to repair or reinforce them. Pull the top of the stanchion inwards, and press it outwards with your foot. Check for flexing and cracking at the anchorage point, and for evidence of loose fastenings at the deck.

Pulpits

Pulpits should be anchored to the deck with bolts and load spreading plates wherever necessary. Inspect the condition of the anchorage plates, and check for bends in the pulpit tubing. Evidence of collision damage should prompt inspection of the welds and anchorage points. Check the condition and suitability of the fairleads and anchor cable fittings on the foredeck. These should be designed to prevent the cable jumping out of the fairlead and pulling against the pulpit supports.

Lifelines

Just as with marine tubular fabrications, check for fatigue and corrosion. Plastic-coated or stainless steel wire is just as likely to be weakened as galvanized wire. Check particularly the point where the wires pass through the stanchions. Tensioning screws should be in line with the wires, and wired up or locked to prevent them from unscrewing. Shackles should be wired, and cotter pins held with a split pin or clip. Lanyard tensioning lashings should be tight, and in good condition. Test wires by forcing them down towards the deck. Apply downwards pressure midway between stanchions.

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