DISTANT BLUE - Ohlson 38

Copyright © 2012 Charles McGrory 

DISTANT BLUE 

RENOVATION – A WORK IN PROGRESS… 

2011 

CHARLES MCGRORY 

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Underbody Renovation 2011 Distant Blue 

Moisture readings standards. 

Readings are not actual percentages but a relative reading 0 – 100 with actual approximately 1 – 4%. 

0 ≤ 15 Very good Dry 

15 ≤ 20 Satisfactory: Slight moisture of no concern. 

21 ≤ 30 Moderate: Some moisture present but not considered a defect. 

30 ≤ 45 High: Risk of moisture-related defects. 

45 ≤ 60 Very High: Probable Osmotic condition 

60 ≤ 100 Extremely High: Probable Laminate Degradation 

Hull below waterline 

No evidence by tapping with hammer of delamination or voids. Actual state of laminate cannot be 

completely guaranteed without destructive testing. 

Distant Blue Moisture testing conditions: were good for testing 

Air temperature: 

21◦ C 

Above dew point: 

8.4 ◦ C 

Surface temperature: 

19.6 ◦ C 

Relative Humidity: 53% 

Readings were as follows: Sovereign Quantum: Scale 0 – 100 

Shallow Mode Deep Mode 

Range above waterline: 14 – 16 13 – 21 

Range below waterline: 16 – 32 21 – 36 

The surveyor cautioned that, “there was risk of moisture-related defects but none were visually 

apparent. He added that careful control of water in bilges, and ventilation, especially over winters 

ashore may assist in keeping moisture levels from rising and may allow them to diminish.” 

He added, “The epoxy layer on the hull was of unknown vintage, but judging from the number of 

different layers of antifouling on the hull above the epoxy, it had been in place for many years. 

Consideration should be given to removing all the layers of depleted antifouling and ‘keying’ the 

surface and applying more layers of epoxy as the moisture resistance of the original is outside the 

guaranteed performance criteria (normally 10 years). 

Osmosis chemistry and Boat Hulls 

“Osmosis is the movement of solvent molecules through a partially permeable membrane into a region 

of higher solute concentration, aiming to equalize the solute concentrations on the two sides.” 

Wikipedia 

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My comments: Osmosis and Osmosis Blistering 

The actual osmotic travel of water into the laminate on a gross scale would not be good for the 

laminate. However, it is my understanding that the problem is substantially aggravated when such 

water migrates and finds a ‘void’ within the laminate and when such a ‘void’ contains un-reacted 

polyester, left over from production, then a reaction kicks in to result in osmosis blistering which can 

be severe. This is likely aggravated by salt water and any chemicals picked up in an industrial 

harbour. The longer the hull is immersed in water, the greater the potential for osmotic migration of 

the outside water into the boat hull. 

A winter ashore will help decrease the migration and given ventilation and heat there would be some 

release of the water back to atmosphere, restrained by the underbody coatings and shield which 

would be preventing release back to atmosphere. 

Distant Blue Construction 

I accepted the surveyor’s report, cautions and recommendations and bought the boat. I had seen no 

indications of blistering and noted that there were indications of good construction e.g. the hull deck 

joint flange of some 15-20mm was clean and stable with no indications of any leakage down through 

the teak toe-rail bolts from twisting or warping of the hull-deck. The original Lloyds A1 inspection 

certificate was present. A previous French potential buyer who was considering the boat for a sailing 

school backed off when he heard there was moisture present. 

Distant Blue hull was designed in 1960s built to 1960s specifications in 1979/80 in the days of thick 

GRP construction. The Tyler reputation came from their use of clear laminates where they could see 

any voids and likely in those days, slow careful squeezing of the laminates and resin, reducing 

substantially the chances of voids and un-reacted polyester. Leaving the hull to cure carefully in the 

mould would assist in the completed reaction of any polyester leaving no reactant left. 

I considered that any problems were not imminent and could be prevented and the modern boat did 

not provide any more stable expectation and was not the sea boat I wanted. 

‘Modern’ Cored Construction and Design vs. Ohlson 38 

Many boats from the late 70s and on into 1980s, began to move to thin GRP skins and balsa-cored 

hulls; also the increased demand caused pressure on production managers to fast-cure or cut short 

the long cure-time in the moulds. CS Yachts in Toronto in the 1980s had severe problems of osmosis 

blisters in new yachts under five years old. They then offered new owners an upgrade cost option to 

seal the hull with shield; not sure if this changed their speed of process in the moulds. 

C & C yachts near Toronto had moved to balsa-cored hulls and decks. I know of one ten-year old boat, 

C & C 36 where the deck was rotting around the stanchions. The problem with balsa-cored boats, 

while claiming to have epoxy-sealed balsa segments in the core, is that if water migrates through the 

hull by osmosis into the balsa, then water may start to ‘liquefy’ the balsa. On this C & C 36, it was 

quite possible to take the stanchion, waggle it around and watch the deck deflect. Found this out 

halfway from Bermuda to Boston! Also the spade rudder was very tiring to steer in Force 7-8 seas. 

In our harbour in Sarnia, Ontario, a C & C 39 came in from the summer cruise in Lake Huron. She had 

hit a rock and divers sent down reported no obvious damage other than a dent in the lead fin keel. 

She was then sailed all summer. The end of season she was hauled out and later that winter at some 

20◦ C below, the hull all around the keel ‘exploded’. Water had migrated into the balsa from cracks in 

the hull along the keel base where the keel had torqued on the impact of the collision with the rock; 

the expansion of the water turning into ice ruptures the hull along the keel length and for nearly a 

metre outboard. So you can see I am not a great admirer of ‘modern’ sandwich construction. 

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‘Modern’ Hull Design 

Ohlson 38 and Contessa 32 designs are with a long fin keel, skeg and rudder with long V overhanging 

bow and ‘wineglass’ hull sitting deep in the water. I was really pleased with the Contessa 32 

performance in all weathers especially in the steep seas of the Great Lakes but I wanted more space 

inside. 

A year before I bought Distant Blue, I had sailed a Beneteau in Toronto and a Bavaria 32 in Scotland’s 

Firth of Clyde. Both boats are ‘modern’ design with low weight sandwich construction which allows 

high topsides, large volume hulls, fat bows and spade rudders; they sit up on the water and with high 

windage and wide bows have poor upwind performance in choppy seas; they are tiresome to steer 

with the spade rudders. So that is part of the background why I searched for and bought an Ohlson 

38. Any upgrade work was a valid investment on a known vessel of pedigree. 

Distant Blue Underbody Renovation 

The boat had been out of the water from spring 2010; the survey was in October 2010 so to that 

extent the hull may have dried a little. I followed the surveyor’s recommendation to provide 

ventilation and heat. There was only the small companionway louvre available which I left open; I set 

up a dehumidifier and a tube heater in the main cabin I removed all the cushions and removed the 

access wooden panels from the bunks etc. 

The boat was sandblasted in approximately March 2011; there had been years of antifouling which 

needed to come off; I was assured by Joshua of Suffolk Yacht Harbour that the light-touch blasting 

would not affect the gel coat. The hull underbody appeared quite sound with no blistering and was 

smooth other than damage to the keel which had been observed by the surveyor; it was worse than 

we thought and was repaired. The rudder showed signs of having been bored and drained of water at 

some time. 

After blasting 

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The original Gelshield was much lower than the current waterline and somewhere the boat had 

become heavier than the designer’s marks. We think this is perhaps due to the heavy cabinetry or 

that the designer made a mistake or the hull layup was heavier than spec. Still a mystery… 

You can see the original LWL and original dark Gelshield. 

And the massive oversize boot-top limit. 

Now the LWL is about 6cm above the tip of the aft tip of the rudder. 

Rudder with signs of prior maintenance drainage of water 

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Keel damage was a wee bit of a shock. 

Worse than we thought 

Now fully repaired 

After the sanding etc three coats of new Gelshield were applied. 

Gelshield Topside and Gold Coveline applied 

The mountings for the Hydrovane can be seen on the counter 

The topsides were repainted with ‘Awlgrip’ to a superb finish; actually it is ‘Awlcraft’ which is easier to 

retouch which was put to test after an incident at the dock. A novice sailor though they were doing me 

a favour by applying power as the boat was being handed off the dock; the power caused the bow 

cutwater to collide with the dock and scuff the paint; this was buffed off with no additional painting; 

the Awlcraft is soft enough and was thick enough to be moved over the scuff. The yard Suffolk Yacht 

Harbour had applied four coats of paint, baked on. The novice has not been invited back as yet… still 

thinking about it… 

We had a lot of concern as to where the waterline was truly since she was on the hard when I bought 

her and she had a massive boot-top which made the boat look clumsy and inelegant. The yard gave 

me a free hoist and dunk and Nick Fairhurst marked the LWL as she floated, with a margin of some 

50mm for safe loading. 

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Distant Blue – just out of shop 

I am delighted with the results; she is much admired. Many other yachtsmen came by and asked what 

type of boat she was. Right now she is out of the water and being further upgraded. In all perhaps she 

will have been out of the water about 23 months total again with heater and dehumidifier. 

Looking forward to next launch! 

I am also very pleased with the all the staff at Suffolk Yacht Harbour who gave me their skill and 

enthusiasm to bring her back to pedigree standing and in particular Joshua Major for his overall 

coordination and interest; Nick Fairhurst who managed the project with detailed care and helpful 

suggestions; Howard who did the woodwork, Robert who installed the Hydrovane and Andrew who 

installed the new Forehatch. 

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Distant Blue – new beginnings 

The Dream-Ship tugs.... 

with the stirring of the sea. 

The creaking tackle... 

break the stillness of the dawn, 

while morning dew glistens... 

chill in the thin light. 

Hushed voices knock on the hollow air. 

Ropes run out, halyards running, 

shaking her sails as flapping happy wings, 

My Ship wakens from her sleep 

to slip and slide thro the ruffled water. 

Ropes alive, tiller kicking, 

Bow wave tumbling, hissing, 

Quivering.... she leans, 

to hear the whispers of the wind. 

As she dips in gentle curtsey 

to the heave of the ocean roller, 

the clouds rush by on the ocean of the sky. 

Sunlight dances on the golden brine. 

Bear up! My Ship, 

that we may find, in the Distant Blue... 

the promise of this day, that's yours and mine! 

Copyright (c) 2011 Charles McGrory 

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DISTANT BLUE - Ohlson 38

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